Deteriorating CL tune

[joe_lyons]

Delphi literature shows 450°C for both.  The ST & dynas have the mini sensors much closer to the port than the touring but mabie that's what the stamped bungs do is to shield the heat?

[FLTRI]

Delphi literature shows 450°C for both.  The ST & dynas have the mini sensors much closer to the port than the touring but mabie that's what the stamped bungs do is to shield the heat?

No problem with placement differences as long as polling times are commensurate with placement.
Arbitrarily changing O2 placement 18mm or 12mm assuming CL system operation will be correct is IMO not good.
Bob

[wurk_truk]

Yup,  but even the dynas are still a foot from the port.  If using adaptors, they will be IN the port, this is what I am thinking.

Sent from Buckeye Tuning

[Tsani]

Well this is a issue I am working on now. O2 placement. I have a set of stock 07 softail (FLSTNI) header pipes. The original placement stinks in my opinion. May work ok with stock mufflers but not with my Cycleshacks. Was looking at the setup in a 2013 FLSTNI and they are now putting the bungs pretty far away from the exhaust ports. Now I know the two wire O2s I am using are different from the new ones, the bung location in the stock 07 setup has to put them pretty much out of the flow especially the front one which is right after the inside radius of the first bend. I can imagine that the exhaust flow almost creates a dead spot there with a more open exhaust. The rear is probably ok, just need to correct the fact that the stock bungs do not allow the tip of the sensor to be in the flow adequately. I just got some low, fully threaded bungs and am going to place the into a stock head pipe. The front location is the one I am having a hard time deciding on as it will have to go on the inside area of the pipe (frame side). Yeah I know, the outside of the ppe would be better but I do need to consider looks as well.

[FLTRI]

Well this is a issue I am working on now. O2 placement. I have a set of stock 07 softail (FLSTNI) header pipes. The original placement stinks in my opinion. May work ok with stock mufflers but not with my Cycleshacks. I just got some low, fully threaded bungs and am going to place the into a stock head pipe. The front location is the one I am having a hard time deciding on as it will have to go on the inside area of the pipe (frame side).

Is there some of the bung you can take off? Just getting the sensor deeper into the pipe at its present location may be enough to get good readings.

That said, if you intend to relocate remember to make sure the sensor nose is pointed downhill not uphill as you don't want condensation to gather. Water can kill an O2 sensor.

It would not be the end of the world if you identify the closed loop problem areas and tune them from where you are now. Usually the problem areas are found below 40 kpa. Above that exhaust pressure should be enough, even with cycle shacks unless you have bent the tab inside. There should be about 1/4" at the widest part of the opening.
Bob

[joe_lyons]

Yup,  but even the dynas are still a foot from the port.  If using adaptors, they will be IN the port, this is what I am thinking.

.
I think this is closer than a foot

[rbabos]

Yup,  but even the dynas are still a foot from the port.  If using adaptors, they will be IN the port, this is what I am thinking.

.
I think this is closer than a foot

Interesting. I notice my v rod has a similar fabbed pocket in the pipe. Shooting for the same goal likely.
Ron

[joe_lyons]

All of the softails, dynas and vrods have these o2 bung setups stock and Vance and Hines is using them also

[wurk_truk]

In answering Hrdtail78s question, in is NOT good practice to use an adapter and place a 12mm sensor into a bung made for a NON heated sensor.  The heater elements WILL burn up if too much heat is applied.  C'mon dude, just think logically for a moment.  A heated sensor exists why?  Our 18mm sensors are from 1976.  They were designed to get as hot as possible as fast as possible... from the HEAT generated by the exhaust ports...  and the auto companies got tired of having to replace these because of thermal shock and all of that.   Heater circuits allowed the O2s to come online way faster to control things faster (less emissions).  The heaters HAVE to toggle the heat on and off.  CAN"T run a heated sensor at a higher temp than the heater circuit.

[rbabos]

In answering Hrdtail78s question, in is NOT good practice to use an adapter and place a 12mm sensor into a bung made for a NON heated sensor.  The heater elements WILL burn up if too much heat is applied.  C'mon dude, just think logically for a moment.  A heated sensor exists why?  Our 18mm sensors are from 1976.  They were designed to get as hot as possible as fast as possible... from the HEAT generated by the exhaust ports...  and the auto companies got tired of having to replace these because of thermal shock and all of that.   Heater circuits allowed the O2s to come online way faster to control things faster (less emissions).  The heaters HAVE to toggle the heat on and off.  CAN"T run a heated sensor at a higher temp than the heater circuit.

Intersting. I always thought the heated sensor was more of a preheat device to speed up the time it takes for the exhaust to bring it up to operating temp. After calibrating the wide bands that I've used with heaters I can still put my hand on them after. As you pointed out, I'm a crowbar mechanic when it comes to electrical crap but this observation has me leading to O2 heaters as more of a preheat device to speed up control on a started engine. School me.
Ron

[redmtrckl]

It's discussions like this that I sure miss Steve Cole's input.

[rbabos]

A little more than a preheat device.  There are times when you can cool the 18's enough to send them off line.  Long decel for example.  In this case the 12's heater will kick on and heat them.  I am sure this would be seen more with the 12's down by the trans case if they were not heated.  I had to chase a bad sensor.  Keep the kpa up and the sensor worked fine.  Lower kpa the sensor kept going off line.  New sensor fixed the problem.  I understand this doesn't prove anything about the heater being bad, but... that what it points to for me.

Steve would be some help with this.  But... He also might state some facts and confuse some guys. 

Truk,
You have the best chance living through an ambush if you charge it.

I'll buy that. Sounds like the heated might be better overall then for vtuning or autotuning depending on your Tuner fetish.
Ron

[wurk_truk]

Ron... you are EXACTLY correct.  They ARE a pre heat device to get the engine under control as fast as possible.  This IS for emissions testing purposes, etc.  But, in older crap, the O2s depended upon the engine heat, they placed them as close as possible to the source of the heat as they could... faster operation meant the engine is 'under control' sooner.

No biggie.

Now, though, the newer 12mm O2s DO have the heaters circuits.  They WILL heat an O2 to 1350F from what I have recently read on the Bosch DE site.  (Bosch.USA site sucks).  The 'heater' is regulated by the ECM, eventually.  These heaters are NOT self controlled.  I AM saying that the heater circuit needs to have enough control to regulate that heat.  Too close to the head, and the heater circuit COULD lose control, and burn up the heater circuit.  This IS the why they are moved a bit from the port, so they the heater circuit can see both the low temp AND the high temp and regulate.  AND... what it DOES heat is the Nernst cell inside, not the whole O2 sensor, or that is what a cutaway looks like to me.

ANd, Joe, you are also correct in it is when the sensor is POLLED by the ECM.  Nothing is read 100% of the time.  AN ECM is constructed similar to a PLC and it involves scans and scan rates.  The ECM has an instruction inside to 'look' at the O2 at a certain time after the combustion event.

I called SC  last year to ask about this vis-a-vis a touring bike.  He said the 'polling' takes place in a wider area than exactly where the stock O2s are located.  I would be OK as long as my front pipe was about to the brake pedal and the rear pipe was at the front of the clutch cover.  Also, never have an O2 closer to the 'exit' of the PIPE (BEFORE collector) less than 5 diameters of the pipe in question.

On a Dyna?  I think anywhere up there would be good, but my OPINION is there will be too much heat right next to the valve.

[joe_lyons]

Here is a small amount of info on the mini sensors.

[attachment removed after 60 days by system]

[ultraswede]

Its a shame that Delphi use the term "switching" sensors, since the sensors themselvs do no switching!

The ECU does the switching.

[Hilly13]

Its a shame that Delphi use the term "switching" sensors, since the sensors themselvs do no switching!

The ECU does the switching.

I agree, I think it causes a lot of confusion for some people, the sensor reports a voltage, what is important is when that voltage is checked.

[Scotty]

Its a shame that Delphi use the term "switching" sensors, since the sensors themselvs do no switching!

The ECU does the switching.

The sensor's voltage switches from high to low depending on what it reads in the pipe.

Maybe that is why they call it a switching sensor.

[FLTRI]

Its a shame that Delphi use the term "switching" sensors, since the sensors themselvs do no switching!

The ECU does the switching.

The sensor's voltage switches from high to low depending on what it reads in the pipe.

Maybe that is why they call it a switching sensor.

I believe ultraswede is 100% correct.
The O2 sensor can only read O2 content and send a voltage to the ECM. The ECM decides if the system is rich or lean then adjusts the fueling to drive the system to the opposite.
Ie: If lean voltage output (typically <450mv) the system drives richer fueling. When the sensor reports rich O2 content (typically >450mv) the system drive fueling lean...and the process repeats.
This is why they are called switching sensors but they do no switching...all switching occurs in the ECM.
Bob

[ultraswede]

I used to tune my 5.3 Tahoe with Hptuners.

Since there was one o2 sensor for 4 cylinders and stock cam, it run extremely stable.

If I set the AFR to 14,7-1 open loop (possible on that combo) the 02s would read a steady 0.45v, the graph was straight line.
i.e. the sensors only report a voltage, if the AFR is constant, so is the o2 voltage.

[Scotty]

Its a shame that Delphi use the term "switching" sensors, since the sensors themselvs do no switching!

The ECU does the switching.

The sensor's voltage switches from high to low depending on what it reads in the pipe.

Maybe that is why they call it a switching sensor.

I believe ultraswede is 100% correct.
The O2 sensor can only read O2 content and send a voltage to the ECM. The ECM decides if the system is rich or lean then adjusts the fueling to drive the system to the opposite.
Ie: If lean voltage output (typically <450mv) the system drives richer fueling. When the sensor reports rich O2 content (typically >450mv) the system drive fueling lean...and the process repeats.
This is why they are called switching sensors but they do no switching...all switching occurs in the ECM.
Bob

Hmm your explanation is exactly what I said but you said Ultraswede is 100% correct?!?

The sensors voltage is either above 450mv (rich) or below 450mv (lean) so it reports voltage OR you could describe that as the voltage switching from high to low to which the ECM responds by driving the fuel richer or leaner.

So I would suggest that the sensor switches voltage from above or below 450mv and as the ECM reads this voltage it drives the fuel richer or leaner

Play on words I suspect but I will go with the manufacturer on this one 

[Coyote]

The O2 sensors are clearly switching sensors. The spend 99.9% of their time in one of two states. The ECM uses them as a crude A2D converter.

[rbabos]

The O2 sensors are clearly switching sensors. The spend 99.9% of their time in one of two states. The ECM uses them as a crude A2D converter.

Any sensor I heated with a torch shows constant voltage. Switching high/low has to come from the ecm but the base voltage comes from the sensor. Don't know how you can claim the sensor itself is a switching senor. What am I missing?
Ron

[Coyote]

I'm not sure how you measured it but it likely needs a wetting voltage. But the sensor is doing the switching.

http://www.boschautoparts.com/oxygensensors/pages/premiumoxygensensors.aspx



edit. Perhaps I'm misunderstanding your statement. What drives the switch is the change in the afr which is controlled by the ECM. The voltage swing from the sensor is driven by the sensor in response.

[rbabos]

I'm not sure how you measured it but it likely needs a wetting voltage. But the sensor is doing the switching.

http://www.boschautoparts.com/oxygensensors/pages/premiumoxygensensors.aspx



edit. Perhaps I'm misunderstanding your statement. What drives the switch is the change in the afr which is controlled by the ECM. The voltage swing from the sensor is driven by the sensor in response.

That's ok. I get misunderstood all the time. Let's go with what you think I said.
Ron

[FLTRI]

Switching sensor does not relate to any switch in the sensor.
All it can do is report voltage.
100% of the switch comes from and caused by the ECM NOT the sensor.
The ECM says too lean and richens the mixture only to find out its to rich and leans the mixture.
So othe switching is actually just voltage crossing over say 450mv but the sensor switches nothing...just the ECM.
Just the way I understand it, BWTFDIK?
Bob