Why understanding Sensors is important

[Steve Cole]

This is just to be a discussion on Sensors Only. What they do and what they do not do. I've attached a datasheet for a MAP sensor from Delphi. This is typical of what a MAP sensor does, from all manufactures in the automotive market place. Look it over and let's have a discussion about it.

[FLTRI]

Sure would be nice to understand how the MAP sensors work in a short little common intake.
Since we know there's crosstalk it's hard for me anyway, to understand how the ECM makes it work.
Bob

[harley_cruiser]

I have read a lot about what the MAP sensor does but never found out how it does it, not sure if I could read it if I found that information but would love to know.

[whittlebeast]

Can we talk about default map, map read 1, map read 2, egr, map and how they all relate.

Andy

[akjeff]

This is just to be a discussion on Sensors Only. What they do and what they do not do. I've attached a datasheet for a MAP sensor from Delphi. This is typical of what a MAP sensor does, from all manufactures in the automotive market place. Look it over and let's have a discussion about it.

I'll take a stab at it. The MAP measures the pressure of the intake manifold, relative to ambient air. This, coupled with the intake air temp, and engine RPM help the ECM calculate the amount of air entering the intake(the VE table if you will), so it knows how much fuel to deliver, to give the AFR in the cell that most closely matches the condition at that moment in time.

Jeff

[whittlebeast]

You must keep in mind that the pressure in the intake, on a wobble fire motor is insanely dynamic.  It is this pressure change compared to the missing teeth that is used to figure out where in 720 degrees of rotation, the motor is at any given time.

A MAP sensor is way faster of a reacting device than you would think.

Andy

[joe_lyons]

Map sensor is a pressure and vac sensitive sensor.  It has a flexible silicon chip that is factory calibrated and then Dependant on its range it is able to go from close to 0 to 300 kpa.  Ours are only operable between near 0 to 100ish kpa. 

The cam tune/map tooth read is what decides where to take the read from.  This can change the readings at idle and affect your EGR table. 

Steve I just don't know if the poll of the map is taken from one to the other or is it 2 separate polls?  Could you explain to us in a little more detail when we are choosing the cam tune point what is it that we are actually seeing.  I know the procedure but just not exactly why.

[dynaglide]

I still don't understand how it actually works 

Since the pressure in the manifold is "insanely dynamic", which I take to mean "varies greatly over the course of each crankshaft revolution", how does the ignition module (I have a carbed bike...) know which of the many different pressures to use for the ignition timing?  Does the MAP sensor average the pressure over a given time?  Or does it report to the ignition module in "real time" and the module does the averaging?  And over what timeframe does it average the readings?  Once every crank rev?  Something else? 

[whittlebeast]

I am trying to locate a MAP log off a Harley at the tooth level.

[dynaglide]

are you referring to the missing tooth on the flywheel?  So I guess the ignition module correlates the MAP sensor readings with the flywheel "timing mark" (missing tooth)?  And only uses the sensor reading for that particular instance (which I assume would also be the same particular instance it uses to determine the ignition timing)?

[Steve Cole]

Please reread the title of the post and my first post. Lot's of people here trying to go beyond just understanding a sensor and so far not one of you has answered the question properly. Read the attached datasheet and lets get everyone of you up to understanding just what the sensor is, and what it can and cannot do.

[rbabos]

Please reread the title of the post and my first post. Lot's of people here trying to go beyond just understanding a sensor and so far not one of you has answered the question properly. Read the attached datasheet and lets get everyone of you up to understanding just what the sensor is, and what it can and cannot do.

Not sure what the correct answer is? To me it's nothing more then a variable resister that changes voltage output to the ECM based on manifold pressure.
Ron

[a2wheeler]

interesting that this sensor provides two outputs.
They provide two separate
outputs critical to air/fuel ratio optimization:
• One voltage output proportional to engine intake manifold
pressure
• Thermistor output proportional to manifold air temperature

[Coyote]

Please reread the title of the post and my first post. Lot's of people here trying to go beyond just understanding a sensor and so far not one of you has answered the question properly. Read the attached datasheet and lets get everyone of you up to understanding just what the sensor is, and what it can and cannot do.

Not sure what the correct answer is? To me it's nothing more then a variable resister that changes voltage output to the ECM based on manifold pressure.
Ron

There would have to of been a question first. There was none.   

[a2wheeler]

as for the goal - "understanding just what the sensor is, and what it can and cannot do."
It just provides a voltage amount that represents the kpa and the temp. That is all, it does not do anything else. Those outputs are available for other things to read and use that input for various logic processes.
There are ranges and accuracy for both outputs, and I presume it is reasonably fast at reacting to changes , and therefore the output provided is its best delivery of the current status of those two metrics.

[harley_cruiser]

Map sensor is a pressure and vac sensitive sensor.  It has a flexible silicon chip that is factory calibrated and then Dependant on its range it is able to go from close to 0 to 300 kpa.  Ours are only operable between near 0 to 100ish kpa. 

The cam tune/map tooth read is what decides where to take the read from.  This can change the readings at idle and affect your EGR table. 

Thank you Joe, that makes since.

[Steve Cole]

Please reread the title of the post and my first post. Lot's of people here trying to go beyond just understanding a sensor and so far not one of you has answered the question properly. Read the attached datasheet and lets get everyone of you up to understanding just what the sensor is, and what it can and cannot do.

Not sure what the correct answer is? To me it's nothing more then a variable resister that changes voltage output to the ECM based on manifold pressure.
Ron

There would have to of been a question first. There was none.   

OK, so I missed the "?" but others seem to have read it how I hoped "What they do and what they do not do"

I have tired to limit the discussion to just Sensors so people can learn about them. If they understand what they can and cannot do the rest of it all becomes easy to understand. The problem I see is most people really have no idea how they work or what they can and cannot do. I provided a current Delphi MAP datasheet with all the necessary information from Delphi so it can be discussed. In this case it can measure two different parameters and provide an ouput (for each)that represents the results of it's measurements. It also tells you how accurate each measurement can be and in what range. So a2wheeler is the only one who got to the first part of the question, "What they do"

[FSG]

So what is the actual question then?   Spell it out or better still edit your original post so that it is obvious.

[fbn ent]

I find this interesting. So the sensor basically measures the negative pressure in the manifold and the intake air temperature? I am assuming that we will be going through all the sensors (kinda like Preacher's Son & Professor Poop ) Anything to learn more stuff!

[whittlebeast]

All pressures are positive in the EFI world.  0 is no air, 100 is close to sea level.

[a2wheeler]

I think what is important about this sensor is that it does not tell you 0 or 100 or anything in between. It only provides a voltage. What ever is reading this voltage has to understand the value and its mapping to a range of 15 - 102kpa.

[hrdtail78]

I find this interesting. So the sensor basically measures the negative pressure in the manifold and the intake air temperature? I am assuming that we will be going through all the sensors (kinda like Preacher's Son & Professor Poop ) Anything to learn more stuff!

Might look through the sticky's and look for several topics of this nature by Steve.   Good stuff that merited a sticky.  It's always a bit bumpy in the beginning but after guys get their shots in.  They progress nicely with good info in them.

[fbn ent]

Thanks for that. LOTS of good information there.

[BVHOG]

In simply terms it measures engine load based on pressure changes.

[98fxstc]

There is a requirement for a given air/fuel ratio at operating conditions.
The air intake determines the fuel required.
Oxygen levels in air vary with temperature so we need to measure the temperature of the air
The air intake by the motor varies with load/rpm so we need to measure how much volume of air the motor is sucking in
so map sensor to measure vacuum
all sensors convert convert measurements to electrical signals (voltage,current or resistance) which are processed by the ECM
Things that come into play are the absolute accuracy of the sensors and the relative accuracy of the sensors in the range in which they are working
These sensors appear to be pretty accurate over the range in which they are working
Whether or not the ECM gets the correct information is determined by the environment in which they are working
Map , for example , whether the signals may be affected by crosstalk between the cylinders

Might be jumping the gun here , but compare these sensors with narrow band O2 sensors which are only accurate in part of the range in which they are working , and are also influenced by crosstalk between pipes , and EGR

[Steve Cole]

Guys, forget what may or maynot happen to an ENGINE or ECM this is ONLY about the SENSOR. If you do not have a firm understanding of how a sensor works you are never going to understand how other devices work with them.

MAP sensor is what we are currently trying to work with, later after you understand it, maybe we can move on to other SENSORS ONLY discussions.

MAP = Manifold Absolute Pressure, that means something and all of you have skipped over it or do not understand it, not sure which yet.

[a2wheeler]

This link has some good detail, however it is based on the auto systems.
It has this same Q&A -
What is absolute pressure?
In absolute measurement, the zero point (where the measuring device indicates zero) is an absolute zero pressure. That means no pressure, or in other words, a 100% vacuum.

http://www.fastfieros.com/tech/map_sensors_and_how_they_work.htm

[98fxstc]

The engine creates a vacuum in the intake manifold relative to the outside atmospheric pressure
ie a region of negative pressure
MAP sensors measure absolute pressure
so that 0Kpa (zero pressure) is the absence of pressure
and 100 kPa equates to maximum pressure

[98fxstc]

And we're not talking about IAT sensors yet ?

[akjeff]

Guys, forget what may or maynot happen to an ENGINE or ECM this is ONLY about the SENSOR. If you do not have a firm understanding of how a sensor works you are never going to understand how other devices work with them.

MAP sensor is what we are currently trying to work with, later after you understand it, maybe we can move on to other SENSORS ONLY discussions.

MAP = Manifold Absolute Pressure, that means something and all of you have skipped over it or do not understand it, not sure which yet.

I'll guess that you're referring to the A in MAP, as in Absolute? Breezed right by that. So the MAP measures(or rather puts out a voltage proportional to) absolute pressure. Pressure relative to absolute zero pressure, rather than barometric pressure. Sensors don't really measure anything, as they merely output a voltage, current, resistance. It's up to whatever device this V,I, or R is fed, to intemperate it, as use it as desired.

Jeff

[joe_lyons]

Absolute pressure is from absolute 0 and to below atmospheric pressure.

[akjeff]

Absolute pressure is from absolute 0 and to below atmospheric pressure.

I'll respectfully disagree. Absolute pressure is from absolute zero on up. It can be either above or below barometric.

Barometric pressure is whatever the ambient air pressure is, relative to absolute zero.

Gauge pressure, is pressure(or vacuum), relative to barometric pressure.

Jeff

[Coyote]

 Pressure measured in the TB is below atmospheric.  As the load on the engine goes up, the pressure in the TB drops relative to outside.

[akjeff]

Pressure measured in the TB is below atmospheric.  As the load on the engine goes up, the pressure in the TB drops relative to outside.

My understanding is that as the load on the engine increases, the manifold pressure increases to nearly that of atmospheric? Or another words, as load increases, the amount of vacuum in the intake drops to nearly zero(i.e. atmospheric) But, I've been wrong before!

Jeff

[Coyote]

You know Jeff I do believe you are correct. As the TB opens, the Absolute pressure will rise. Thanks for making me think about it. I had in my mind the old vacuum gauges but that's not the same as the MAP sensor.

[akjeff]

You know Jeff I do believe you are correct. As the TB opens, the Absolute pressure will rise. Thanks for making me think about it. I had in my mind the old vacuum gauges but that's not the same as the MAP sensor.

:up:Doesn't happen often!

[dynaglide]

Guys, forget what may or may not happen to an ENGINE or ECM this is ONLY about the SENSOR. If you do not have a firm understanding of how a sensor works you are never going to understand how other devices work with them.

MAP sensor is what we are currently trying to work with, later after you understand it, maybe we can move on to other SENSORS ONLY discussions.

MAP = Manifold Absolute Pressure, that means something and all of you have skipped over it or do not understand it, not sure which yet.

You're clearly fishing for some particular answer that you're not getting. Instead of having us try to guess the "correct answer" that you apparently already know, how 'bout you tell us what you're trying to say?  After all, isn't the point of this forum for the rest of us to learn, rather than getting frustrated?

[Steve Cole]

Absolute pressure is from absolute 0 and to below atmospheric pressure.

I'll respectfully disagree. Absolute pressure is from absolute zero on up. It can be either above or below barometric.

Barometric pressure is whatever the ambient air pressure is, relative to absolute zero.

Gauge pressure, is pressure(or vacuum), relative to barometric pressure.

Jeff

This is the correct answer, but look at how many people did not know what it is. The whole idea for me is to get you to understand the basics and being able to know what the sensor is and what it is capable of doing. So now that you know WHAT it is, now lets talk about what it can and cannot do. The sensor does not give a rats ass about an engine or what it does. This is why I have stated to limit the discussion to just the sensor. All it does is measure absolute pressure and temperature and output a voltage. Page 3 of the document shows the pressure error and temperature error along with the transfer curve for the MAP portion of the sensor.

So if we assume the sensor is mounted in a chamber and that chamber is at 20 kPa absolute pressure what would the sensor read or tell us the absolute pressure is?

[joe_lyons]

.5ish volts.  Could be off +- 3.9ish KPA

[FLTRI]

So if we assume the sensor is mounted in a chamber and that chamber is at 20 kPa absolute pressure what would the sensor read or tell us the absolute pressure is?

Anywhere between 17.6 to 22.4 without temp error so anywhere from 16.1 to 23.9 with temp error.
Bob

[whittlebeast]

But that is the product sheet.  What is the repeatability of any given one sensor as installed on any given bike?  What about as it rises to 30 kpa?  What if it lowers to 30 kpa?

[joe_lyons]

I confused about this.


It says its the table for temp but says its in kpa? 

[fbn ent]

I used -1.7 for the temp adjustment --- I got 15.9 - 23.90 kpa. Of course that number would come from reading the voltage of the sensor.

[a2wheeler]

At 20 kpa, the chart shows an allowable error of +/- 2.4 kpa.
This matches FLTRI - "Anywhere between 17.6 to 22.4 without temp error"

[FLTRI]

But that is the product sheet.  What is the repeatability of any given one sensor as installed on any given bike?  What about as it rises to 30 kpa?  What if it lowers to 30 kpa?

But the question was what is the reported KPA when the sensor is inside a chamber @ 20kpa.
Answer that,
Bob

[a2wheeler]

That temperature error multiplier chart is confusing. It appears that there is a +/- 1.5 kpa affect on kpa reading across the entire temperature range. However , it calls it a multiplier - could that be 1.5 times the already listed +/- 2.4kpa - ending up with  +/- 3.6 kpa.

[Coyote]

That temperature error multiplier chart is confusing. It appears that there is a +/- 1.5 kpa affect on kpa reading across the entire temperature range. However , it calls it a multiplier - could that be 1.5 times the already listed +/- 2.4kpa - ending up with  +/- 3.6 kpa.

That's the way I read it.

[FLTRI]

That temperature error multiplier chart is confusing. It appears that there is a +/- 1.5 kpa affect on kpa reading across the entire temperature range. However , it calls it a multiplier - could that be 1.5 times the already listed +/- 2.4kpa - ending up with  +/- 3.6 kpa.

I'll bet you're correct...I missed the "multiplier" and took it for +/- 1.5 KPA error.
Bob

[joe_lyons]

1.5 above and 1.75 below is what it looks like

[a2wheeler]

1.5 above and 1.75 below is what it looks like

I agree, that bottom portion looks a bit over 1.5.  Must not be too important as they did not provide a good Y axis scale to read. I'm sure I'll get shot for that "not be too important". LOL

[Bike31]

I thought the purpose of the MAP was to estimate the air density (mass) of the incoming air. Mass = air pressure, temperature, and humidity. The last component being unknown in this case. Depending upon mass and rpm (estimate of intake air volume) the ECM determines fuel flow (Edit: and timing of ignition). My 0.02.

[joe_lyons]

Would this be more appropriate?

[joe_lyons]

Or is that other table just the error for temperature output?

[guydoc77]

I'm sure I'll get corrected however isn't the big picture that the MAP sensor reads whatever it reads to allow a calculation on the momentary air flow into the motor? And that calculation is used in an algorithm to determine the injector PW.

So the question is what does the MAP measure.
Flow or pressure or whatever. Given the units it is pressure and given the Delphi attachment temp as well, and it's output is in voltage.

Here's my question. In a NA motor the pressure in the manifold can't ever really be above ambient pressure correct? As the piston moves down with an open valve the only pressure available to fill the void being created is atmospheric pressure. We speak in terms of vacuum and that works for me intellectually but is there really vacuum or is the air just rushing in due to Delta P between the outside of the engine (current barometric pressure) and the momentary lower pressure in the cylinder? In other words, if I'm some little person from Gulliver's Travels, and I'm standing in the intake manifold where the MAP sensor is mounted, aren't I just going to feel wind blowing on me? Wind after all, is just air moving along pressure gradients. Stronger the wind, the higher the gradient(s). In a VTwin motor that wind is dependent on throttle position, RPM, cam specs, valve open or closed, heads, and position of piston(s) in cylinder.

Let the grilling begin.

[tjwallib]

Using 1.5 for the temperature error multiplier for both plus and minus variation,,,,,,,the sensor in a chamber with a 20kpa pressure could give us a reading anywhere from 23.6kpa to 16.4kpa,,,,,at least that's my "take" on it.

[whittlebeast]

This will all turn out to be very academic once we get to the fueling equation.

[guydoc77]

This will all turn out to be very academic once we get to the fueling equation.

Agreed...

[fbn ent]

I'm sure I'll get corrected however isn't the big picture that the MAP sensor reads whatever it reads to allow a calculation on the momentary air flow into the motor? And that calculation is used in an algorithm to determine the injector PW.

So the question is what does the MAP measure.
Flow or pressure or whatever. Given the units it is pressure and given the Delphi attachment temp as well, and it's output is in voltage.

Here's my question. In a NA motor the pressure in the manifold can't ever really be above ambient pressure correct? As the piston moves down with an open valve the only pressure available to fill the void being created is atmospheric pressure. We speak in terms of vacuum and that works for me intellectually but is there really vacuum or is the air just rushing in due to Delta P between the outside of the engine (current barometric pressure) and the momentary lower pressure in the cylinder? In other words, if I'm some little person from Gulliver's Travels, and I'm standing in the intake manifold where the MAP sensor is mounted, aren't I just going to feel wind blowing on me? Wind after all, is just air moving along pressure gradients. Stronger the wind, the higher the gradient(s). In a VTwin motor that wind is dependent on throttle position, RPM, cam specs, valve open or closed, heads, and position of piston(s) in cylinder.

Let the grilling begin.

I know where you are coming from but in the '57 Dodge pickup the only way to really get the vacuum wipers to work was to let off the throttle....

[FLTRI]

This will all turn out to be very academic...

I think that is the purpose.
Bob

[joe_lyons]

I'm sure I'll get corrected however isn't the big picture that the MAP sensor reads whatever it reads to allow a calculation on the momentary air flow into the motor? And that calculation is used in an algorithm to determine the injector PW.

So the question is what does the MAP measure.
Flow or pressure or whatever. Given the units it is pressure and given the Delphi attachment temp as well, and it's output is in voltage.

Here's my question. In a NA motor the pressure in the manifold can't ever really be above ambient pressure correct? As the piston moves down with an open valve the only pressure available to fill the void being created is atmospheric pressure. We speak in terms of vacuum and that works for me intellectually but is there really vacuum or is the air just rushing in due to Delta P between the outside of the engine (current barometric pressure) and the momentary lower pressure in the cylinder? In other words, if I'm some little person from Gulliver's Travels, and I'm standing in the intake manifold where the MAP sensor is mounted, aren't I just going to feel wind blowing on me? Wind after all, is just air moving along pressure gradients. Stronger the wind, the higher the gradient(s). In a VTwin motor that wind is dependent on throttle position, RPM, cam specs, valve open or closed, heads, and position of piston(s) in cylinder.

Let the grilling begin.

I know where you are coming from but in the '57 Dodge pickup the only way to really get the vacuum wipers to work was to let off the throttle....

Yes because you are restricting the flow of air with the throttle blade causing a vac and that's how the wipers worked.  Full throttle slow to no wiper movement, decell would have great wiper movement.  Today's lesson is just about the sensors.

Are we hitting the point Cole?

[Steve Cole]

Great, Now you are looking and reading, That's a good thing as you can see for yourself the Sensor is incapable of giving you an exact reading. All we know for sure is that it is within a range of values based on the tables listed. As long as it gives a reading within that range the sensor itself is doing it's job. That doesn't mean each and everytime you are going to get the same reading, it just means it will be within the allowable range of values. No matter what anything else does, with the sensor it can never be better than what the sensor itself is capable of doing. Now it can be worse (and many times is) if you do not apply and use the provided corrections. In this case it is temperature correction and yes it increases the range of error.

So why is this very important?  The main reason is you have to allow for these errors and KNOW they are there to start with. So if, the amount of error is unacceptable, from this sensor you must move to a better piece if it exist. In many cases there will be some better and some worse. When this is the case you have a choice to balance cost again quality but in some cases there just is no choice.

[fbn ent]

So, please explain Steve. What is this "multiplier" for temperature?

[joe_lyons]

I'm sure I'll get corrected however isn't the big picture that the MAP sensor reads whatever it reads to allow a calculation on the momentary air flow into the motor? And that calculation is used in an algorithm to determine the injector PW.

So the question is what does the MAP measure.
Flow or pressure or whatever. Given the units it is pressure and given the Delphi attachment temp as well, and it's output is in voltage.

Here's my question. In a NA motor the pressure in the manifold can't ever really be above ambient pressure correct? As the piston moves down with an open valve the only pressure available to fill the void being created is atmospheric pressure. We speak in terms of vacuum and that works for me intellectually but is there really vacuum or is the air just rushing in due to Delta P between the outside of the engine (current barometric pressure) and the momentary lower pressure in the cylinder? In other words, if I'm some little person from Gulliver's Travels, and I'm standing in the intake manifold where the MAP sensor is mounted, aren't I just going to feel wind blowing on me? Wind after all, is just air moving along pressure gradients. Stronger the wind, the higher the gradient(s). In a VTwin motor that wind is dependent on throttle position, RPM, cam specs, valve open or closed, heads, and position of piston(s) in cylinder.

Let the grilling begin.

The MAP sensor just measures absolute pressure where as a TMAP sensor also has a thermistor built in for convenience and space saving.  Yes, in theory you can not exceed the current barro pressure. 

[tjwallib]

My guess is the "lesson" is that we're dealing with a number of possible variations from "actual" events/conditions with the current sensors/systems on the HD fuel injection system. There maybe alternatives in the market place, but are they cost effective and applicable on a car or motorcycle for everyday use.

Knowing that the information available provided to the ECM's internal programs could be so wildly variable, we need to come to terms with it.

NB O2 sensors have "tolerances" in their outputs, WB O2 sensors have "tolerances" in their outputs,  MAP sensors have "tolerances" in their outputs, the combustion process in an engine is not a "stable" event from revolution to revolution.  Let the ECM and internal programming do it's thing and work with the "averages" and ranges of info that it receives.

I am by no means an expert, as I know many of the good folks on this forum could "bury me" with their knowledge and experience in tuning bikes well. But I sometimes think that folks are trying to pick "fly sh*t" out of pepper when it comes to the process,,,,,,,when in many ways it doesn't really matter because the info/data we're receiving from the sensors is so potentially variable.

Not many of the folks on this forum or out there on the road are racing their bikes where the last "tid bit" of power is actually useable or will make a difference. We just want a bike that will perform well and reliably,,,,,,,hopefully better than our buddies that we ride with.

I know I'm a "newbie" on the forum, my intention isn't to piss anyone off. I enjoy the reading and learning.

[joe_lyons]

My guess is the "lesson" is that we're dealing with a number of possible variations from "actual" events/conditions with the current sensors/systems on the HD fuel injection system. There maybe alternatives in the market place, but are they cost effective and applicable on a car or motorcycle for everyday use.

Knowing that the information available provided to the ECM's internal programs could be so wildly variable, we need to come to terms with it.

NB O2 sensors have "tolerances" in their outputs, WB O2 sensors have "tolerances" in their outputs,  MAP sensors have "tolerances" in their outputs, the combustion process in an engine is not a "stable" event from revolution to revolution.  Let the ECM and internal programming do it's thing and work with the "averages" and ranges of info that it receives.

I am by no means an expert, as I know many of the good folks on this forum could "bury me" with their knowledge and experience in tuning bikes well. But I sometimes think that folks are trying to pick "fly sh*t" out of pepper when it comes to the process,,,,,,,when in many ways it doesn't really matter because the info/data we're receiving from the sensors is so potentially variable.

Not many of the folks on this forum or out there on the road are racing their bikes where the last "tid bit" of power is actually useable or will make a difference. We just want a bike that will perform well and reliably,,,,,,,hopefully better than our buddies that we ride with.

I know I'm a "newbie" on the forum, my intention isn't to piss anyone off. I enjoy the reading and learning.

There is a lot of "picking fly $hit out of pepper".  And the end all is making the motor happy.  Sometimes the ECM cannot comprehend everything or control it.  Sometimes we have to finagle things to make to motor happy.

[Coyote]

Guys, subsequent posts should be kept on topic. If you don't like the material or how it's presented or the presenter, then do not participate in this topic. Thanks.

[UltraNutZ]

Joe, couple of questions for you sir.

   
• what is the specific range the ECM is capable of compensating for on it's own say for the VE tables, and AFR? 
• Does that compensating range vary by model year or specific part # of ECM itself? 
• Is it a % number or is it a set number depending on the table?

Thanks
NutZ

[UltraNutZ]

disregard my question Joe.  the more I think about it, the ECM in my mind is nothing but a 12v powered calculator that calculates what the sensors are feeding it.

[FLTRI]

disregard my question Joe.  the more I think about it, the ECM in my mind is nothing but a 12v powered calculator that calculates what the sensors are feeding it.

[whittlebeast]

This EFI stuff gets really easy once you understand the basic sensors and the basic math that the "calculator " is using.  In the Harley world, the map sensor is by far, the most complex.

This thread keeps skirting around the interesting part of the MAP sensor and how the ECU is forced to deal with what the sensor is "seeing" in the intake.

[fbn ent]

I have a feeling we will get there.

[rageglide]

Sitting in my seat, pencil in hand, hater filter turned on.  Ready to learn as much that fits in my head.       

[Bike31]

If it somehow doesn't work perfectly would we know it?

[whittlebeast]

If it somehow doesn't work perfectly would we know it?

Errors of a couple of pct, it is doubtful you would ever notice.  A dead sensor is very noticable and very easy to diagnose  with the tools to look.  Electrical noise in the sensor wiring fooling the ECU, can be more challenging to find.

[rbabos]

This EFI stuff gets really easy once you understand the basic sensors and the basic math that the "calculator " is using.  In the Harley world, the map sensor is by far, the most complex.

This thread keeps skirting around the interesting part of the MAP sensor and how the ECU is forced to deal with what the sensor is "seeing" in the intake.

Don't know why you would say forced to deal with. Wouldn't the code be set up and calibrations to work within it's enviroment? Then it would be normal, just different then say a 4 banger with a normal intake .
Ron

[UltraNutZ]

i also don't understand what the interesting part about that specific MAP sensor is?  It measures absolute pressure within the intake just as it would if you take it out and lay it on the table and has an operating range with an accuracy range just like any other measurement device.  No matter how you slice and dice it, the sensor will be operating within those specifications and no more.  That is unless it's jacked up to begin with.

[98fxstc]

I dont think there is anything special about the map sensor
I think the exercise is to demonstrate the accuracy of the values obtained

the Sensor is incapable of giving you an exact reading. All we know for sure is that it is within a range of values based on the tables listed. As long as it gives a reading within that range the sensor itself is doing it's job.

The main reason is you have to allow for these errors and KNOW they are there to start with.

Actually , the sensor is capable of giving an exact reading , not all the time , and we dont know when it is and when its not , only that it will be within the specified range.

[Steve Cole]

This is just to be a discussion on Sensors Only. What they do and what they do not do. I've attached a datasheet for a MAP sensor from Delphi. This is typical of what a MAP sensor does, from all manufactures in the automotive market place. Look it over and let's have a discussion about it.

Lots of things posted that have had nothing at all to do with my original post. I started this so people who wanted to learn could, those that already know it all can just skip over this. This is still about "Sensors Only" as stated in my original post and until people understand them there is no sense going any further. I want to cover ALL the sensors that are used on a HD engine equipped with a Delphi Fuel injection, not anything else.

I dont think there is anything special about the map sensor
I think the exercise is to demonstrate the accuracy of the values obtained

the Sensor is incapable of giving you an exact reading. All we know for sure is that it is within a range of values based on the tables listed. As long as it gives a reading within that range the sensor itself is doing it's job.

The main reason is you have to allow for these errors and KNOW they are there to start with.

Actually , the sensor is capable of giving an exact reading , not all the time , and we dont know when it is and when its not , only that it will be within the specified range.

Correct, there is nothing special about a MAP sensor, all it does is measure Absolute Pressure and in the case of a T-MAP it is two sensors in one. One measures Absolute Pressure and the other measures Temperature. Each and every sensor is just as simple in that it just takes a measurement. They do not care how, what or why. In the question I post before I asked what would you get for a reading if the real pressure was 20 kPA, and if you look at some of the answers provided, some still do not get it. Since you know the answer (20 kPa) and the sensor has a range of values it could report , what is the range of error in percent possible?

[UltraNutZ]

according to Joe's drawing it would be roughly 8%


according to the manufacturer's drawing it would be roughly 5%

[a2wheeler]

I get +18% to -21%.   3.6/20 = 0.18   and 4.2/20 = 0.21

[a2wheeler]

Jumping ahead, but if the actual value was 60kpa, then the sensor could be reporting +3.8% to -4.3% .
2.3/60 = 0.038 , 2.6/60 = 0.043

[98fxstc]

I get +18% to -21%.   3.6/20 = 0.18   and 4.2/20 = 0.21

I think the temperature multiplier comes into play
1.5 x +18% and 1.7 x -21%

[a2wheeler]

I was using Joe's chart, which already has the temp multiplier applied.

[whittlebeast]

The MAP in a Harley is very dynamic.  The VE and spark lookups are looking for a single MAP for process.  What number do you use?  Peak min?  Average?

[FLTRI]

The MAP in a Harley is very dynamic.  The VE and spark lookups are looking for a single MAP for process.  What number do you use?  Peak min?  Average?

Yep, and now we know how much error is stacked up in the MAP equation! I would say the Delphi ECM works miracles with all that fudge factor!
And it's no wonder why other, aftermarket systems, have issues.
Bob 

[joe_lyons]

Not to mention it bounces around a bit.

[Steve Cole]

Now your getting somewhere! This isn't fly "Potty mouth" in the pepper, in some ranges it is, while in other ranges it's huge cow pies. Before you even apply a temperature correction at 20 kPa it is +/- 8.3% for a range of 16.6% plus the temperature correction. Now move to a real 40 - 94 kPa and your looking at a different amount again. Then move all the way to the end at 102 and you have yet another range of error.

So I hope this has opened some of your eyes, this is all there is and you must deal with it from just this one sensor. How about all the others? I can tell you none of the other MAP sensors are any better than this in the automotive world either so HD isn't better or worse than them. So the truth is simply that this sensor gives an indication of what the real MAP maybe but by no means is there a guarantee, its exactly right. Depending on the value it is trying to measure, it's closer in some areas and further off in others.

OK so which SENSOR do you all want to look at next? I can try and find public documents for them. Let's limit this to the sensors until you begin to understand what they all can and cannot do. This is where it all starts, and as you can see there is plenty of people what don't know about them.

[q1svt]

Thanks SC

NB O2's

[UltraNutZ]

I may be the ignorant one here but wouldn't it be repeatable - predictive as long as it's within it's operating specifications per the manufacturer?  Or if it fails altogether?     

[Just Nick]

Great topic Steve
My vote is for the narrow bands

And thank you mods for keeping this one on topic with out all the bs   Thumbs up

[glens]

Should I take it that you don't know how repeatable any given sensor is?  16% is two full AFRs give or take.

Any given TMAP sensor is very likely to fall at relatively consistent places within its operational envelope, don't you think?  The 16% is more like unit-to-unit than what any given unit will do day-to-day I'd think.  If so, I'd also think, even if it does eventually cover the whole 16% range it will be over many hours, not every few seconds.  Thus a comprehensive ECM calibration derived with/for the particular sensor should prove to hold (in terms of what the sensor is responsible for) for a good while IMO.

Ah, the beauty of closed-loop feedback with long-term trims.  Should greatly extend the length of time the good tune holds.

[Bike31]

Is it possible to exceed the working range of the TMAP by replacing cams, intake or exhaust? Any experience in doing that is what I'm asking.

[UltraNutZ]

I think glens explained what I was trying to say better than I did if I'm reading his post correctly.

IE:
Sensor A - is a 5vdc sensor with a 10% tolerance + or -.  So that sensor is ALWAYS going to read somewhere between -4.5vdc and +5.5vdc.  That is the repeat ability I am referring to.  I didn't in any way mean that it would read 5.23vdc or any given vdc 80% or even 50% of the time.  Only that it will ALWAYS read within it's tolerance and it will do so every time unless something is wrong with it.

This is irrespective of what tuning device, what cam, what head, what cylinder, who the manufacturer is, etc..  We're not talking about all that stuff.  We're simply talking about the sensor itself in no given application just that it's a sensor.

[Steve Cole]

The output from the sensor will tend to stay relatively the same, until conditions change, this is typically called sensor drift. What I mean is if your in the same conditions it will tend to read the same on that one sensor. Now if you look at another day that is say 40 degrees hotter out they will typically move or change from where it read before. As an example if the real pressure is 20 kPa and your sensor on a 30 degree day read 23 kPa, it may, on a 70 degree day, read a real pressure of 20 kPa as 19 kPa. This is all within the range that the sensor is capable of so it's not bad or even out of specification.

As for over reading a TMap by adding cams and such the SENSOR has no way to even know you made those changes

[glens]

I think glens explained what I was trying to say better than I did if I'm reading his post correctly. ... I didn't in any way mean that it would read 5.23vdc or any given vdc 80% or even 50% of the time...

I was rather implying that it would read very near 5.23 even more than 80% of the time given the same circumstances.

The output from the sensor will tend to stay relatively the same, until conditions change, ... As an example if the real pressure is 20 kPa and your sensor on a 30 degree day read 23 kPa, it may, on a 70 degree day, read a real pressure of 20 kPa as 19 kPa...

And that individual sensor will undoubtedly drift a little over time, but in the shorter term it will fairly predictably repeat the 23 kPa @ 30 degrees and 19 kPa @ 70 degrees (heating and shaking it the same each time), wouldn't you say?

[hrdtail78]

Wouldn't the temp be based on IAT and not temp of the day?  That temp seems to be a constant changing thing as well.

[glens]

You've got the temperature of the sensor itself (housing) as an operational variable.  Unless 100% of the electronics are 100% thermally insulated from that.

[Steve Cole]

The output from the sensor will tend to stay relatively the same, until conditions change, ... As an example if the real pressure is 20 kPa and your sensor on a 30 degree day read 23 kPa, it may, on a 70 degree day, read a real pressure of 20 kPa as 19 kPa...

And that individual sensor will undoubtedly drift a little over time, but in the shorter term it will fairly predictably repeat the 23 kPa @ 30 degrees and 19 kPa @ 70 degrees (heating and shaking it the same each time), wouldn't you say?

Yes, the one sensor will fairly repeat from what we have seen and measured. The thing you have to remember is that they can all be different within the specification, if you test 20 of them or they could all be kissing cousins. What we see typically is that if the sensors are all from the same build batch they are closer to each other, but get a mix batch from different production builds and you can for the most part test them and separate them in to piles and then look at the build ID's on them and you find you separated them by the production build information.   

While it's not the end of the world, it is one of the variables you have to understand and deal with the best you can.

[joe_lyons]

How would we deal with this any differently than we would before we knew the tolerances? 

[hrdtail78]

We don't.  Mapping to a break point is mapping a breakpoint.  Hopefully a sensor that is drifting one way drifts that way enough to map the break points.  When things don't go as advertised.  That is when understanding the data being collected becomes important.  To understand data collected does mean understanding how and what is being collected.

Like Glen said.  Thanks for the "hidden tables" that have different break points that help in the average's of the break points we have that are "unbidden."

[akjeff]

OK so which SENSOR do you all want to look at next? I can try and find public documents for them. Let's limit this to the sensors until you begin to understand what they all can and cannot do. This is where it all starts, and as you can see there is plenty of people what don't know about them.

I'd like to know more about the knock sensing system.

Jeff

[Bike31]

I'd like to know why, with all the tech and sensors, HD apparently leaves power on the table?

It's not in their interest as far as sales, and the CARB data I've read doesn't show marginal emission standards: http://www.arb.ca.gov/msprog/onroad/cert/cert.php#6

Is it a matter of a threshold of noise or emissions, and if so, how close do they take the stock tune?

At what level of tune are the regulatory thresholds exceeded?

It would seem with all the sensor tech that something's preventing improved compliant performance in a stock bike.

[BVHOG]

OK so which SENSOR do you all want to look at next? I can try and find public documents for them. Let's limit this to the sensors until you begin to understand what they all can and cannot do. This is where it all starts, and as you can see there is plenty of people what don't know about them.

I'd like to know more about the knock sensing system.

Jeff

Me too but the knock sensor is after all the spark plug. it would be interesting to know why some setups(cals/builds)are so finicky and some are not.   Would be interesting to know if the sensitivity of this function can be altered.

[hrdtail78]

OK so which SENSOR do you all want to look at next? I can try and find public documents for them. Let's limit this to the sensors until you begin to understand what they all can and cannot do. This is where it all starts, and as you can see there is plenty of people what don't know about them.

I'd like to know more about the knock sensing system.

Jeff

Me too but the knock sensor is after all the spark plug. it would be interesting to know why some setups(cals/builds)are so finicky and some are not.   Would be interesting to know if the sensitivity of this function can be altered.

Yes, it can be altered.

[FLTRI]

... knock sensor is after all the spark plug.

Well yes, but the spark plug is only part of the ion sensing modeling mix. Sparkplug condition, gap, and wires also affect ion sensing feedback.

From what I've seen the Delphi ion sensing does an admiral job with stock plugs and wires.
Once aftermarket plugs and/or wires have been installed all bets are off with expecting proper ion (knock) sensing.

Improper knock retard is most prevalent with high performance (high compression) builds but I have seen it with bone stock bikes, especially with the latest bikes.
Bob

[rageglide]

I'd like to understand why ion sensing was used instead of traditional knock sensors. 

Is Ion sensing so advanced it has additional value?  Or is this a cost saving thing, (2 knock sensors and associated wiring.)

[fbn ent]

I know this is a discussion of sensors but I need to know...so we cannot use non Harley spark plugs? I have heard this but poo-pooed it as HD propaganda.

[FLTRI]

I know this is a discussion of sensors but I need to know...so we cannot use non Harley spark plugs? I have heard this but poo-pooed it as HD propaganda.

Ask the guys who tune for a living about aftermarket plugs and wires.
Bob

[hrdtail78]

You don't have to use the champion HD plug.  NGK also makes plugs for HD.  NGK tech told me that the plug that cross reference from the HD stock plug is built with the same resistance as the stock plug.  That is why it is the cross reference, and is made to work with the ion sensing system.

Real world.  I use NGK pn 4179 (non screw off cap) on a lot of higher compression builds.  Knock system still works, but if I do ever see a problem or question a maybe problematic situation.  I do check it out with every thing stock.

A tradition knock sensor is basically a microphone listening for a specific sound.  Engine modifications can affect that sound.  So it can not work so great when adding modifications to an engine.

[rageglide]

S&S IST uses traditional peizo knock sensor.   A lot of folks like that ignition and who knows what kinds of cams/mods.

I do know of a case where IST had big issues due to this.  a v113 crate motor where S&S didnt get the wrist pin clips in correctly.. the owner would hear noises from the wrist pin making contact with the cylinder wall, and the knock sensor would retard timing.  Lots of issues with that engine.  It ran pretty good when the knock sensor was unbolted from the head.  Until it totally failed.

[joe_lyons]

Add some square lobe cams and crazy springs and that microphone is always going off.

[rageglide]

Add some square lobe cams and crazy springs and that microphone is always going off.

I agree it seems non-workable.  But S&S IST still uses that technology and lot of people love that set up.  Maybe they have their cams valvetrain frequency pattern filtered out and moving to a different 'signature' is too far out of spec.

[FLTRI]

Add some square lobe cams and crazy springs and that microphone is always going off.

Yep. It's a fine line when it comes to accelerometers used for knock sensors for high performance builds.
Ion sensing is definitely tunable so hopefully someday there will be some fancy programming that will allow for sensitivity adjustment.
Bob

[joe_lyons]

617 cals need it bad

[Steve Cole]

617 cals need it bad

We do not seem to have that type issue with our TTS 617 calibrations. The 613 and 614 were not very good.

[rageglide]

Add some square lobe cams and crazy springs and that microphone is always going off.

Yep. It's a fine line when it comes to accelerometers used for knock sensors for high performance builds.
Ion sensing is definitely tunable so hopefully someday there will be some fancy programming that will allow for sensitivity adjustment.
Bob

IST must filter or else they would have no end of issues.  Listening only for a specific pinging signature should work, but clearly it's not infalible.  Maybe S&S should filter valve train signature, period.  My friend with his IST was picking up a sticking valve and retarding, S&S used logging to (mis)diagnose this and rebuilt the rear head based on it.  Turned out to be the piston pin/flapping oil ring (the ring land was gone from the damage).

I don't know why our current ECM option doesn't include the ability to tweak Baselines, or filter data.  Maybe it does... ie calibrating or setting a baseline for the T-MAP.  Granted its' easier to hard code the mfgr spec for the part and adjust on the fly.   But, shouldn't be a big deal to 'calibrate' and insure you don't have additional slop in the mix.  Some sensors might be more accurate always, and some may be sloppy always. 

Just thinkin outloud.  Maybe I should keep thoughts in my head.   

[joe_lyons]

617 cals need it bad

We do not seem to have that type issue with our TTS 617 calibrations. The 613 and 614 were not very good.

Yes I've heard that you tuned down the sensitivity in the cal but I know stock, SEPST, and PV 617 cals are extremely sensitive with knock.  Idk how all the other ones like DL, fuel pack, or vigilante do?  Mabie they just don't like me? 

[FLTRI]

Definitely there are new sensitivity issues. The trick is not to turn down the sensitivity but be able to properly identify the knock.
I believe the old cals did an admiral job but these new cals make poor judgement calls and can pull as much as 11 degs I've seen...for no good reason.
In the olden days 8 degs was default max.
Bob

[hrdtail78]

I would bet most of those tuners mention just use the same as SE, or what is already there in the ECM.   There is a lot to it.  Ever talk to dyno jet vision tech about knock control?  They aren't getting in there and doing anything with it any time soon. 

[Admiral Akbar]

While this discussion is a little too scattered for me to follow there is one thing I've noticed about most automotive sensor data sheets, they suck.. With years of looking at data sheets from TI, National Semi, and Analog Devices (there are others but haven't been around as long), I guess I'm spoiled..  Don't see and specs for drift (short long or over temp), or propagation delay..  Both Dephi and Bosch data sheets suck.. Worked on a project that used a 3 axis Bosch accelerometer..  Data sheet was a

[FLTRI]

While this discussion is a little too scattered for me to follow there is one thing I've noticed about most automotive sensor data sheets, they suck.. With years of looking at data sheets from TI, National Semi, and Analog Devices (there are others but haven't been around as long), I guess I'm spoiled..  Don't see and specs for drift (short long or over temp), or propagation delay..  Both Dephi and Bosch data sheets suck.. Worked on a project that used a 3 axis Bosch accelerometer..  Data sheet was a

I think you're getting the message SC is trying point to...you can only be as good as the +/- error stack up with the sensors the ECM relies on.
One can't simply make more resolution in order to show a picture a certain way.

We are dealt with these variances, drift, repeatability, etc, consequently, and as I've said, it's all about the run/ride quality, fuel mileage, and smooth, responsive experience.

I have also realized there is no way a human can do better than dynamic O2 readings to keep tight reins on a performance bike.

Must have good O2 sample quality and/or be able to identify and eliminate area(s) where sampling is not reliable and leave it in open loop.
Bob

[harleytuner]

While this discussion is a little too scattered for me to follow there is one thing I've noticed about most automotive sensor data sheets, they suck.. With years of looking at data sheets from TI, National Semi, and Analog Devices (there are others but haven't been around as long), I guess I'm spoiled..  Don't see and specs for drift (short long or over temp), or propagation delay..  Both Dephi and Bosch data sheets suck.. Worked on a project that used a 3 axis Bosch accelerometer..  Data sheet was a

I think you're getting the message SC is trying point to...you can only be as good as the +/- error stack up with the sensors the ECM relies on.
One can't simply make more resolution in order to show a picture a certain way.

We are dealt with these variances, drift, repeatability, etc, consequently, and as I've said, it's all about the run/ride quality, fuel mileage, and smooth, responsive experience.

I have also realized there is no way a human can do better than dynamic O2 readings to keep tight reins on a performance bike.

Must have good O2 sample quality and/or be able to identify and eliminate area(s) where sampling is not reliable and leave it in open loop.
Bob

That's what i'm getting out of this thread as well.

[Admiral Akbar]

While this discussion is a little too scattered for me to follow there is one thing I've noticed about most automotive sensor data sheets, they suck.. With years of looking at data sheets from TI, National Semi, and Analog Devices (there are others but haven't been around as long), I guess I'm spoiled..  Don't see and specs for drift (short long or over temp), or propagation delay..  Both Dephi and Bosch data sheets suck.. Worked on a project that used a 3 axis Bosch accelerometer..  Data sheet was a

I think you're getting the message SC is trying point to...you can only be as good as the +/- error stack up with the sensors the ECM relies on.
One can't simply make more resolution in order to show a picture a certain way.

We are dealt with these variances, drift, repeatability, etc, consequently, and as I've said, it's all about the run/ride quality, fuel mileage, and smooth, responsive experience.

I have also realized there is no way a human can do better than dynamic O2 readings to keep tight reins on a performance bike.

Must have good O2 sample quality and/or be able to identify and eliminate area(s) where sampling is not reliable and leave it in open loop.
Bob

I guess I didn't know what he was doing.. What do "pictures" have to do with it?     I think one point might be that even tho the ECU used a 12 bit a2d that is capable of a 0.02% reading that the number doesn't represent the sensors input down to the 4th decimal place accurately.. If that's the point then the discussion is one step forward in understanding the engineering that needs to go into the system.. Very small part of it tho..

[joe_lyons]

https://www.dropbox.com/s/vsiv7wsr1ijszjn/Map_Sensor_Technical_Specification.pdf?dl=0

https://www.dropbox.com/s/wuc2q7mkxsuy0ns/Map_Sensor_Purpose_and_Function.pdf?dl=0

[FLTRI]

Has anyone here seen evidence that the MAP sensor in acceptable tolerances caused a tuning issue?  Fuel pressure issues can easily cause all sorts of tuning problems and I have never heard of people routinely checking it at WOT in the Harley world.

Andy

Have you taken a peek at the dynamic MAP readings from the HD engine?
If you're asking if a properly functioning MAP sensor causes tuning issue...the answer is I have not seen the horrible MAP anomalies I've heard about with high performance builds.
They've done a good job of filtering out the bad and leaving the good.
Bob

[Admiral Akbar]

https://www.dropbox.com/s/vsiv7wsr1ijszjn/Map_Sensor_Technical_Specification.pdf?dl=0

https://www.dropbox.com/s/wuc2q7mkxsuy0ns/Map_Sensor_Purpose_and_Function.pdf?dl=0

First one much better..

[Don D]

Not being a tuner I have always wondered how a tuner based in the higher elevations could adjust VEs in areas of map pressure that didn't exist due to low barometer? If you can only hit 80 kpa how can 80-100 be calibrated?

[rbabos]

So much for staying on track with sensors considering I got a post pulled that deviated slightly. Typically back to individual chest beating bs, as always. Out of this thread.
Ron

[joe_lyons]

Did some quick searches on my phone but could not find any data sheets for Magneti Marelli stuff for throttle position sensors. Or any for the crank position sensor.  I'm guessing you have access to some of these sheets Steve?

[rbabos]

Has anyone here seen evidence that the MAP sensor in acceptable tolerances caused a tuning issue?  Fuel pressure issues can easily cause all sorts of tuning problems and I have never heard of people routinely checking it at WOT in the Harley world.

Andy

How would they even know, and for that matter how would you?

Look, let's try and get back on track and talk about the various HD SENSORS ONLY. Once you can understand what they can and cannot do then we can talk about how they mix together in another thread about the ECM.

Well then, pick one and let's run with it.
Ron

[FLTRI]

Has anyone here seen evidence that the MAP sensor in acceptable tolerances caused a tuning issue?  Fuel pressure issues can easily cause all sorts of tuning problems and I have never heard of people routinely checking it at WOT in the Harley world.

Andy

How would they even know, and for that matter how would you?

Look, let's try and get back on track and talk about the various HD SENSORS ONLY. Once you can understand what they can and cannot do then we can talk about how they mix together in another thread about the ECM.

Well then, pick one and let's run with it.
Ron

j

I think he did in his OP:
This is just to be a discussion on Sensors Only. What they do and what they do not do. I've attached a datasheet for a MAP sensor from Delphi. This is typical of what a MAP sensor does, from all manufactures in the automotive market place. Look it over and let's have a discussion about it.

Bob

[rbabos]

Has anyone here seen evidence that the MAP sensor in acceptable tolerances caused a tuning issue?  Fuel pressure issues can easily cause all sorts of tuning problems and I have never heard of people routinely checking it at WOT in the Harley world.

Andy

How would they even know, and for that matter how would you?

Look, let's try and get back on track and talk about the various HD SENSORS ONLY. Once you can understand what they can and cannot do then we can talk about how they mix together in another thread about the ECM.

Well then, pick one and let's run with it.
Ron

j

I think he did in his OP:
This is just to be a discussion on Sensors Only. What they do and what they do not do. I've attached a datasheet for a MAP sensor from Delphi. This is typical of what a MAP sensor does, from all manufactures in the automotive market place. Look it over and let's have a discussion about it.

Bob

Bob: Post 86=OK so which SENSOR do you all want to look at next?
Ron

[Steve Cole]

The list as I see it would include Fuel pump, Fuel Pressure Regulator, Injectors, Throttle Position, Crank Position, Engine or Head Temperature, Vehicle Speed Sensor, Clutch position, Intake Air Temperature, Coil, Plug wires, Spark plug, Battery, O2 heated and non heated.

[1FSTRK]

Not being a tuner I have always wondered how a tuner based in the higher elevations could adjust VEs in areas of map pressure that didn't exist due to low barometer? If you can only hit 80 kpa how can 80-100 be calibrated?

Which brings up a really nice feature in the Power Vision, not sure if others have it but you can use either Map vs rpm or TP VS rpm for tuning the late model bikes, The Power Vision gives you this option. If I were worried about altitude adjustments tuning at high elevation then I would certainly use TP vs RPM

How would that make a difference when you go to sea level and the MAP at 100% throttle becomes 100kpa instead of 80kpa? Wouldn't the tune still be off?

[harley_cruiser]

Not being a tuner I have always wondered how a tuner based in the higher elevations could adjust VEs in areas of map pressure that didn't exist due to low barometer? If you can only hit 80 kpa how can 80-100 be calibrated?

Which brings up a really nice feature in the Power Vision, not sure if others have it but you can use either Map vs rpm or TP VS rpm for tuning the late model bikes, The Power Vision gives you this option. If I were worried about altitude adjustments tuning at high elevation then I would certainly use TP vs RPM

How would that make a difference when you go to sea level and the MAP at 100% throttle becomes 100kpa instead of 80kpa? Wouldn't the tune still be off?

Wouldn't the absolute pressure come into affect here, not atmospheric pressure?

[joe_lyons]

As much as a centimeter is related to an inch.

[joe_lyons]

The max pressure that can happen in the throttle body on a NA motor is what the baro pressure is.  98 kpa outside should only equate to a max of 98 kpa in the throttle body but there are correction multipliers in place that can show different.

[a2wheeler]

I think it would be a good idea to end this thread, and start a new one related to a new sensor. Then we would have several sticky threads, each primarily focused on one sensor and only filled with some semi-related tangents.

and maybe it would be nice if someone could wet our appetite by sharing some of the other sensor that come into play along with some of the ECM logic needed in order to handle being tuned at one altitude and running at another. How much do we need to care about, etc. That would be a nice cap to this thread, then on to another sensor in another thread.

[joe_lyons]

I think it would be a good idea to end this thread, and start a new one related to a new sensor. Then we would have several sticky threads, each primarily focused on one sensor and only filled with some semi-related tangents.

and maybe it would be nice if someone could wet our appetite by sharing some of the other sensor that come into play along with some of the ECM logic needed in order to handle being tuned at one altitude and running at another. How much do we need to care about, etc. That would be a nice cap to this thread, then on to another sensor in another thread.

Idk how people cover the 95-100 kpa column where they only are around 80ish kpa with their altitude.  My guess is they probably copy 80 and paste to 95-100 and add 2-5ish to be safe.   This is probably what I would do to cover bases. 

[glens]

Yeah.  I don't care, too.

As far as I'm concerned, 80 kPa is 80 kPa.  If that's all you can get where you tune, it just means 80+ ain't gonna really be tuned unless you pressurize your dyno cell.  Given the choice I'll take MAP/RPM any day over TPS/RPM.  It would be neat, though, to have any kind of TPS table for each column of MAP and use them both, if even just for accel fuel or something.  Hell, maybe the Delphi does already...

[joe_lyons]

The accel fuel is based off of throttle position delta change and whether it is a lambda based cal the VE tables are set up for Map.   So in essence it is kind of set up that away.

[Steve Cole]

The accel fuel is based off of throttle position delta change and whether it is a lambda based cal the VE tables are set up for Map.   So in essence it is kind of set up that away.

Joe

Accelerator Fuel is not based on Delta TPS in a HD Delphi system. There is however, a qualifier, that is looked at but it is one of several that allows the Accelerator function to be active. Once active, it is calculated and delivered based on several tables of information.

[joe_lyons]

Which ones?  I figured TP was a major one at least along with MAP.

[anthonyflhx]

How does fuel additives or octane boosters affect the 02 sensors? Ive heard it destroys them but the amsoil fuel additive claims its safe for oxygen sensors.

[joe_lyons]

The accel fuel is based off of throttle position delta change and whether it is a lambda based cal the VE tables are set up for Map.   So in essence it is kind of set up that away.

Joe

Accelerator Fuel is not based on Delta TPS in a HD Delphi system. There is however, a qualifier, that is looked at but it is one of several that allows the Accelerator function to be active. Once active, it is calculated and delivered based on several tables of information.

OK Steve,  let's talk about TP sensor.

[whittlebeast]

OK Steve,  let's talk about TP sensor.

The biggest thing you need to know about a TPS is in the logs, static is a potential tuning disaster.  When you roll on and off the throttle both slowly and quickly, the graph should be smooth. 

As far as a sensor, they are typically a wire and slider sort of thing and dirt and water will drive then nuts.

The cool stuff is digital now.

Andy

[joe_lyons]

More specifically I guess we can talk about twist grip sensor. 

[joe_lyons]

Twist grip voltage 1 and 2 should both add up to about 5 volts.  When twisted one voltage goes up while the other goes down.

[Steve Cole]

The accel fuel is based off of throttle position delta change and whether it is a lambda based cal the VE tables are set up for Map.   So in essence it is kind of set up that away.

Joe

Accelerator Fuel is not based on Delta TPS in a HD Delphi system. There is however, a qualifier, that is looked at but it is one of several that allows the Accelerator function to be active. Once active, it is calculated and delivered based on several tables of information.

OK Steve,  let's talk about TP sensor.

Well let make sure that everyone knows which sensor we are talking about as you have brought up two different ones. TP has been the name used for Throttle Position. That is the sensor that on a cable bike is bolted to the side of the throttle body. On a ETC bike it is part of the electronics on the side of the throttle body. In your later post you bring up the Twist Grip which is a completely different sensor. So are we going to go over one or the other or both?

[joe_lyons]

Let's just hit everything with throttle position. 

[Steve Cole]

TP or TPS is the result of what the throttle body is doing, it is important to remember "it's the result". So if your working with a cable bike the rider twist the handle bar mounted throttle cable and if its a ETC the rider used the Twist Grip to request from the ECM a different setting of the throttle body and the TPS measures the result.

[whittlebeast]

On the DBW bikes, what are the common modes of failure.  What is the trouble shooting procedure if you own a tuning system?  Just trouble codes or is there modes of failure the the ECU can't detect?

Andy

[harleytuner]

One of the most common problems I've seen with TBW bikes is high idle.  Improper shut down is a culprit. It it's important to shut off the bike using the ingnition south and not the run/stop switch. As already pointed out the voltage between TG 1&2 must always be 5 VDC. If you use the run/stop switch it does a soft shut down of the systems and it's possible that TG 1&2 can be in a transition state and not be 5VDC between them. Next time the bike starts it will default back to where it was shut off and that's what causes high idle. Sitting off with the ignition switch is a hard kill, all the bikes systems shut off instantaneously.

I guess the important thing to know is we are turning off computers now. And just like out computers at home, there is a proper way to do it.

[UltraNutZ]

IMO since you asked Chad.. lol

I don't understand why the issue still persists.  HD spends more time worrying about stupid BS like "infotainment" than trying to resolve some of these electronic issues.  It's not difficult to code into the ECM a reset command signal sent to and received from the TGS at every ignition-on sequence, problem solved.  Nope, too damned worried about Boom Audio...

[Buglet]

    On the cam bus bikes does the bar switch turn off the ing or fuel. Another thing is if you turn of the bike with the bar switch the engine will stop running but the rest of the bike will stay on untill the back wheel comes to a complete stop. Must be the safety police looking out for us.

[joe_lyons]

    On the cam bus bikes does the bar switch turn off the ing or fuel. Another thing is if you turn of the bike with the bar switch the engine will stop running but the rest of the bike will stay on untill the back wheel comes to a complete stop. Must be the safety police looking out for us.

The run switch has 2 operations for off.  There a can signal for off and there is a hard shut off.  That's what the 5th wire is for on the right side.

[Buglet]

    I forget to include to say if you also turn off the main switch everthing still stays on untill the back wheel comes to a complete stop.

[joe_lyons]

One of the most common problems I've seen with TBW bikes is high idle.  Improper shut down is a culprit. It it's important to shut off the bike using the ingnition south and not the run/stop switch. As already pointed out the voltage between TG 1&2 must always be 5 VDC. If you use the run/stop switch it does a soft shut down of the systems and it's possible that TG 1&2 can be in a transition state and not be 5VDC between them. Next time the bike starts it will default back to where it was shut off and that's what causes high idle. Sitting off with the ignition switch is a hard kill, all the bikes systems shut off instantaneously.

I guess the important thing to know is we are turning off computers now. And just like out computers at home, there is a proper way to do it.

I thought this was taken care of in the cals and talked about in TT380?  Ecm keeps powered up for 10 sec after run switch is killed.

[harleytuner]

One of the most common problems I've seen with TBW bikes is high idle.  Improper shut down is a culprit. It it's important to shut off the bike using the ingnition south and not the run/stop switch. As already pointed out the voltage between TG 1&2 must always be 5 VDC. If you use the run/stop switch it does a soft shut down of the systems and it's possible that TG 1&2 can be in a transition state and not be 5VDC between them. Next time the bike starts it will default back to where it was shut off and that's what causes high idle. Sitting off with the ignition switch is a hard kill, all the bikes systems shut off instantaneously.

I guess the important thing to know is we are turning off computers now. And just like out computers at home, there is a proper way to do it.

I thought this was taken care of in the cals and talked about in TT380?  Ecm keeps powered up for 10 sec after run switch is killed.

I believe you are correct Joe, but since we are talking sensors and not tuning I figured it's worth mentioning.  HD has corrected the problem on the newer canbus bikes that only have the handlebar switch.  But there's a lot of bikes out there still running stock calibrations or PC's that still have this issue.  Last time I wrenched/tuned at a dealer was in '08 so if HD came up with a software upgrade for this problem with DTII it was after I left the dealer and went to the INDY.

[Steve Cole]

The issue was solved back in 2009

When looking at it from the sensor level nothing at all changed. Also we should add the Run/Stop switch as a sensor as well as all the other switches to the list of important sensors.

[harleytuner]

The issue was solved back in 2009

When looking at it from the sensor level nothing at all changed. Also we should add the Run/Stop switch as a sensor as well as all the other switches to the list of important sensors.

That still leaves 08 TBW bikes that can still possibly have that issue.

Steve, what about 09 bikes running the same calibrations as the 08 bikes?

[Steve Cole]

All the calibrations for ETC bikes were upgraded in ~ mid 2009 year. So any bike that has the calibration updated along the way has it resolved. It was nothing more than a simple adjustment in the calibration. Since the ECM is learning all the time by leaving the TGS turned slightly after the Run/Stop switch was switched off it learned a new offset. The calibration waited a length of time before it took the necessary reading from the TGS after the Run/Stop switch was turned Off. The fix was adjust the timer to a slightly long wait period, so the the consumer had released the TGS. By teaching consumers to release the TGS and switch the bike off with there right hand, all we did was force them to let go of the TGS so it could return to its idle position. Then the ECM could take the reading it needed without the TGS being slightly twisted from there hand.

[Just Nick]

What sensor is next Steve?