Taking cal out of closed loop question

[07heri]

Lets say I make all my auto tune runs and I'm at 2% change in all my closed loop areas at 14.6

The ECM looks at my target AFR of 14.6....It calculates my AFR based on what my VE value is and what the 02 sensor voltage is.  If lower or higher than 14.6 is adjusts fuel to stay around 14.6. 

Now, I take it out of closed loop and change my target AFR to 14.0.  My VE table stayed the same as it was for 14.6 but the sensors aren't in the picture because I changed the target AFR to 14.0 and took it out of closed loop. 

The ECM sees my same 14.6 VE value but doesn't have any data from the o2 sensors.  How does it calculate my new open loop target value of 14.0?

I can see a tuner sniffing the open looped areas and adjusting the VE to get to my target AFR.   But how does the change to the AFR table from 14.6 to 14.0 do anything without the 02 sensor giving it any data in open loop?  When we changed the AFR table and took the sensors out of the equation isn't the ECM relying solely on our original 14.6 VE value? 

[Coyote]

In theory, once the VEs are correctly calibrated, the ECM can calculate the needed fuel to meet any target AFR. Does not matter if it is in OL or CL.  Being in CL just helps the ECM correct for things that change, like fuel quality, altitude etc.

[07heri]

So the sensors are still online but trims are disabled on open loop?

[Coyote]

So the sensors are still online but trims are disabled on open loop?

Well, the sensors may or may not be in their active region during OL but the ECM will ignore them anyways. When in OL, the ECM does fueling from the VE tables (and the LTFTs) .

[07heri]

Where did it get ltft for the 14.0 afr in open loop if the ve was developed for 14.6 during closed loop auto tune runs?

[Coyote]

Where did it get ltft for the 14.0 afr in open loop if the ve was developed for 14.6 during closed loop auto tune runs?

As I understand the system, LTFT are done in blocks. Depends on the cal what the blocks are but lets say

Low RPM,    Low MAP,  Mid MAP,  High MAP

Mid RPM,    Low MAP,  Mid MAP,  High MAP

High RPM,    Low MAP,  Mid MAP,  High MAP

So those 9 blocks would effect the entire map and the cells, OL or CL within that map.

[Gordon61]

open-loop is when the ECU uses the tables available to calculate how much fuel is needed and chucks that at the engine.

closed-loop is when the ECU is using O2/Lambda sensors to provide feedback to make sure the target AFR is maintained.

closed-loop can be switched on/off in most maps but when on is restricted to the AFR range (Lambda really) of the sensor - narrow-band (stock) or wide-band.

So if you only have stock sensors you can only get closed-loop feedback for AFR of about 14.3 to 15 or so.

open-loop areas of your AFR table (those outside the range of the sensor to control) may benefit from a closed-loop area from the LTFT but not all tuners program LTFT the same.

Anyway, if you don't have any closed loop area in your AFR table, you have no CLI data and no LTFT data

(or that's what the other lot say anyway)

[rigidthumper]

IMO the thing to remember is it's all math-and the old math rules of "equations" apply. If you have determined that 'X' pulse width of fuel is needed, and that is derived from using 'Y' VE and 'Z' AFR desired, the ECM simply computes injector pulse width based on those #s. So, X=Y*Z. If you change the desired AFR, (decrease Z) the ECM should simply produce a new, increased  'X', based on the new numbers being used in the calculations.
This will be accurate, assuming the VE's were correctly calibrated in the first place.

[07heri]

Lets back up.

The bike NEVER ran at 14.0 AFR.....ever.

It was AT with PV at 14.6 and stayed in CL.
I can see LT trims being developed at the 14.6 CL AFR

Now we all hear this....."make AT runs until youre within 5%" then just take it out of CL and richen it up by changing the AFR table"

So back to my question.  The VE's were developed using a CL target AFR of 14.6.  LT trims were established to hover around the 14.6 target AFR using the VE's that were developed, the trims itself, and 02 feedback.

Now we take the AFR table and change it to 14.0 AFR at idle, for example.  We don't have feedback from the 02 sensors at 14.0, just a VE that was dialed in to 14.6.  How does the ECM even get close to the OL 14.0 AFR we are now targeting when changing the AFR table.

[Coyote]

Do what it says. Once you have the VE tables calibrated (at 14.6) then they are (in theory) calibrated at any AFR.  The VEs do not set the amount of fuel the bike gets, they model the air flow through the motor. When you change back to a richer mixture (out of CL) the ECM will know the airflow and new target and calculate the correct amount of fuel for the new AFR.

In reality, you are always better to calculate VEs at the desired AFR which is why there is an AT-100 wideband kit. But you will be close doing it this way with what you have.

[07heri]

Do what it says. Once you have the VE tables calibrated (at 14.6) then they are (in theory) calibrated at any AFR.  The VEs do not set the amount of fuel the bike gets, they model the air flow through the motor. When you change back to a richer mixture (out of CL) the ECM will know the airflow and new target and calculate the correct amount of fuel for the new AFR.

In reality, you are always better to calculate VEs at the desired AFR which is why there is an AT-100 wideband kit. But you will be close doing it this way with what you have.

So if the AFF and CLI are staying pretty tight, within a couple % above or below 100, it should be close when the desired AFR is in open loop.  Its magic lol.

[Coyote]

Once your AFFs are under 5-6% you should be fine.  Keep in mind that you will need to be sure you have adequately hit all the cells. Some areas can be hard to stay in long enough to collect good data.  Logs using widebands are very helpful in spotting these areas.

[Latrobedyna]

Once your AFFs are under 5-6% you should be fine.  Keep in mind that you will need to be sure you have adequately hit all the cells. Some areas can be hard to stay in long enough to collect good data.  Logs using widebands are very helpful in spotting these areas.

Question please You stated that have to adequately hit all the cells. Ok here is a crust of my conundrum. Does it matter what gear there hit in? I am assuming you would want the motor under as much load as possible wouldn't you? If that is the case there no way in hell i ever be able to do that. as one of two things or maybe both would happen. First i am certain i would be flying off a mountain side curve and getting killed at that speed WOT in 6"th gear. Or secondly i would would be bunking with Bubba in the state penn.  So am i o guess i am over thinking this and instead use a lower gear to hit all the cells

[Coyote]

Any given Map vs RPM cell is the same regardless of gear but keeping it there long enough to collect good data is very dependent on what gear you are in IME

[2006FXDCI]

Any given Map vs RPM cell is the same regardless of gear but keeping it there long enough to collect good data is very dependent on what gear you are in IME

When im doing my WOT runs i use a nice long uphill grade on I-80 and do repeated 3-4th gear runs . You will hit every cell in the right lower side of the graph just as well as using 5th or 6th without going 140 mph

[wolf_59]

Any given Map vs RPM cell is the same regardless of gear but keeping it there long enough to collect good data is very dependent on what gear you are in IME

When im doing my WOT runs i use a nice long uphill grade on I-80 and do repeated 3-4th gear runs . You will hit every cell in the right lower side of the graph just as well as using 5th or 6th without going 140 mph

I use 2nd and 3rd for throttle positions up to 30% for lower rpm's then use 4th and 5th from 30-100% TPS to around 3500 rpm then use 3rd gear to finish it off to redline 

[Latrobedyna]

Thank you for clearing that up for me then. I was never able to hit the highest cell's with all them getting a recording.  Maybe Saturday will fix that now. You folks  sure make learning easy 

[07heri]

Once your AFFs are under 5-6% you should be fine.  Keep in mind that you will need to be sure you have adequately hit all the cells. Some areas can be hard to stay in long enough to collect good data.  Logs using widebands are very helpful in spotting these areas.

Question please You stated that have to adequately hit all the cells. Ok here is a crust of my conundrum. Does it matter what gear there hit in? I am assuming you would want the motor under as much load as possible wouldn't you? If that is the case there no way in hell i ever be able to do that. as one of two things or maybe both would happen. First i am certain i would be flying off a mountain side curve and getting killed at that speed WOT in 6"th gear. Or secondly i would would be bunking with Bubba in the state penn.  So am i o guess i am over thinking this and instead use a lower gear to hit all the cells

You won't hit them all on street.  Don't kill yourself trying to.  Find the right stretch of road and ride it somewhat past your "normal" riding style.  If you don't ever see 5000 rpm's during normal riding there's no reason to get wreckless tuning that high.  Tune  a little outside the box of your typical riding style and you will be fine.  Find some steep hills so you can do a couple runs in 5th and 6th where you get into higher map or TP.  If you want to hit the next column ride the brakes a little (dont smoke your brakes) and throttle up.  You won't be impressing anyone showing us how you hit X Y Z squares.  Just be safe.  Is my opinion popular....probably not.  But if you never ride in certain cells why wreck yourself trying to hit them.  If you want a 100%, all cells hit, take it to a reputable tuner....go have a beer so you don't freak when you hear your bike at 6000 rpms lol...and let him do his thing.   

[Karl H.]

   That's a good advice!

[Nexus9]

In open loop, it's far more important that your VE tables are accurate.

You start by setting your true dispacement in the Constants table.  Let's say that's 103.  The progam then calculates that one cylinder, completely filled, will draw in 51-1/2 cubic inches of air.

Now, if we drove around with the throttle blade wide open and no cam overlap, this would be easy - every time the piston vacated the cylinder, 51-1/2 cu in of air would fill the cylinder.  But we vary the throttle blade, limiting the air flow into the cylinder, and at high rpm, cam overlap can actually create a suction that can draw even more the 51-1/2 cu inches into the cylinder.

This is what the VE tables are all about.  Let's say you have a value in a cell in the VE table of 80.  At that exact map/rpm, your cylinder is filling with 80% of the total displacement, or 41.2 cu in of air.  if you now tell the ECM to create a 14/1 air/fuel ratio in your AFR table, it's going to inject just enough fuel to mix with 41.2 cu in of air and be 14/1.

This is why it's so important to get your VE tables accurate if you are going to go open loop.  Imagine I had that VE cell set at 85.  Now I'm telling the ECM that 43.78 cu in of air are entering the cylinder, and it will inject more fuel consistently, because it has no feedback from an O2 sensor to correct it.

Personally, I think an open loop tune runs cooler and more powerful, and you can push the compression more with less detonation.  My leanest cells are set at 13.8.  I really don't care if my fuel mileage is 36 mpg instead of 38 mpg.  But I spent months working on my VE tables.  Once that foundation is in place, you can do a lot with the tune.

[Darreldanger]

In open loop, it's far more important that your VE tables are accurate.

You start by setting your true dispacement in the Constants table.  Let's say that's 103.  The progam then calculates that one cylinder, completely filled, will draw in 51-1/2 cubic inches of air.

Now, if we drove around with the throttle blade wide open and no cam overlap, this would be easy - every time the piston vacated the cylinder, 51-1/2 cu in of air would fill the cylinder.  But we vary the throttle blade, limiting the air flow into the cylinder, and at high rpm, cam overlap can actually create a suction that can draw even more the 51-1/2 cu inches into the cylinder.

This is what the VE tables are all about.  Let's say you have a value in a cell in the VE table of 80.  At that exact map/rpm, your cylinder is filling with 80% of the total displacement, or 41.2 cu in of air.  if you now tell the ECM to create a 14/1 air/fuel ratio in your AFR table, it's going to inject just enough fuel to mix with 41.2 cu in of air and be 14/1.

This is why it's so important to get your VE tables accurate if you are going to go open loop.  Imagine I had that VE cell set at 85.  Now I'm telling the ECM that 43.78 cu in of air are entering the cylinder, and it will inject more fuel consistently, because it has no feedback from an O2 sensor to correct it.

Personally, I think an open loop tune runs cooler and more powerful, and you can push the compression more with less detonation.  My leanest cells are set at 13.8.  I really don't care if my fuel mileage is 36 mpg instead of 38 mpg.  But I spent months working on my VE tables.  Once that foundation is in place, you can do a lot with the tune.

This is an excellent explanation of what is happening...

[Sunny Jim]

When auto tuning basic or pro, the AFR table is dropped anyway, is it not. This in turn sets the VEs for OL presumably. Am I close?

[rigidthumper]

Autotune basic sets the entire area to 14.7, and ussd the onboard 02 sensors for closed loop cal.
Autotune pro sets the entire table to 13.0, and use the widebands for closed loop cal.

[Sunny Jim]

14.7? I thought it was lower than that. 14.2. Perhaps Joe Lyons can confirm.

[Coyote]

14.7? I thought it was lower than that. 14.2. Perhaps Joe Lyons can confirm.

It's 14.6 according to DynoJet. (Although it may be 14.7 for the older maps using a bias table)

The following changes are made to the tune file during the AutoTune process.

AutoTune Pro—automatically applies a .pvv to the tune that does the following:
• Sets the base fuel table to one static value, 13.0 for AFR or .89 lambda.
• Disables EITMS/PE/Adaptive Control.
• AE/DE are still active in the tune, but there's logic to disable or minimize learning when
they're active.


AutoTune Basic—automatically applies a .pvv to the tune that does the following:
• Sets the base fuel table to 14.6 for AFR based calibrations and .982 for lambda based
calibrations.
• Disables AE/DE/EITMS/PE/Adaptive Control.
• Retards 4 degrees of timing.
• Bias the close loop range to .700mv on AFR based calibrations.

General
• Sets calib to PVAT (Session Number).
• Clears adaptive fuel tables after flashing.

[Karl H.]

Due to the CLB set to 700mV the AT Basic is hunting for 14,2 to 14,4.

Karl

[Nexus9]

14.7? I thought it was lower than that. 14.2. Perhaps Joe Lyons can confirm.

It's 14.6 according to DynoJet. (Although it may be 14.7 for the older maps using a bias table)

The following changes are made to the tune file during the AutoTune process.

AutoTune Pro—automatically applies a .pvv to the tune that does the following:
• Sets the base fuel table to one static value, 13.0 for AFR or .89 lambda.
• Disables EITMS/PE/Adaptive Control.
• AE/DE are still active in the tune, but there's logic to disable or minimize learning when
they're active.


AutoTune Basic—automatically applies a .pvv to the tune that does the following:
• Sets the base fuel table to 14.6 for AFR based calibrations and .982 for lambda based
calibrations.
• Disables AE/DE/EITMS/PE/Adaptive Control.
• Retards 4 degrees of timing.
• Bias the close loop range to .700mv on AFR based calibrations.

General
• Sets calib to PVAT (Session Number).
• Clears adaptive fuel tables after flashing.

Sorry, late to the game here.

I'm not familiar with AutoTune, so this may or may not have value... but in TTS, 14.7 is just a "trigger" number that tells the program to use closed loop fedback in this cell.  The actual AFR is adjusted (slightly) by setting the "Bias Voltage" in another table from 250 to 800 (either of those would be extreme).  This biases (is that a word...?) the O2 sensor to produce an AFR of anywhere from 14.2 to 14.6/1, higher bias numbers being richer.