GM.EQIVRATIO problem?

[dmaxfireman]

I am having one hell of a time tuning a 2011 Sierra 5.3 did a short test log to see if I was getting valid data to begin to tune the ve and my GM.EQIVRATIO values were throwing off all of the BEN calculations. This is my first attempt at tuning a gas motor, been tuning diesels since 2006 and this is much tougher!

Every time I would go to the maps the values were all WAY to high (yes I was viewing averages)

Maybe you guys can tell me what I am doing wrong. I will attach some files for you to look at.
Thanks!

[joecar]

Since your ECM (E38) is not a LS1B/411 then GM.EQIVRATIO would be the wrong pid...


the pid you want might be SAE.LAMBDA and you'll have to modify your calc_pids.txt to use this instead of GM.EQIVRATIO.

[dmaxfireman]

Will SAE.LAMBDA interchange or will I have to change the calculation

[joecar]

You have to edit calc_pids.txt like this:

in CLC-00-110, very carefully replace {GM.EQIVRATIO}*{EXT.WO2LAM1} with {EXT.WO2LAM1}/{SAE.LAMBDA}

and save the file

( use Notepad to perform the edit )


edit: I corrected my mistake

[dmaxfireman]

now all values come up as zero? there is a parameter for "BEN factor Bank 1 Serial Wideband E38 style factor" is this what I should be using? The values I get look appropriate.

[joecar]

My mistake, sorry, I meant this: replace {GM.EQIVRATIO}*{EXT.WO2LAM1} with {EXT.WO2LAM1}/{SAE.LAMBDA}

[joecar]

Post a log file containing SAE.LAMBDA and E38.AFRATIO_DMA.

[dmaxfireman]

Log file

[dmaxfireman]

Been reading quite a bit and It looks like I need to use that e38 Ben factor map.

On a tangent, when not tuning should I be leaving the LTFT disabled and only re-enabling the STFT?

Thanks again for all the help I am learning a lot from this and my understanding is growing my the hour!

[joecar]

LTFT's give better trimming than STFT's.

[joecar]

You can use CALC.BEN_2_E38.


( look closely at E38.AFRATIO_DMA and SAE.LAMBDA, they follow each other )

[dmaxfireman]

I think I am making headway, did not clear my fuel trims and was getting some extremely lean numbers on my first couple test drives. So I went back to the stock tune and am at work for 24hrs. Will start playing again on Thursday AM. Now what about sae.lambda vs ext.w02lam once all dialed in should these two values be equal reguardless of fuel used ie. e0 e10 e85? Or do I have to change the lambda value in the serial LC-1 controller that I am using.

[joecar]

Yes, correct, when the air model is correct, EXT.WO2LAM will equal SAE.LAMBDA

( they will be equal regardless of fuel used, you do not have to change anything in your LC-1 )


i.e. {EXT.WO2LAM1}/{SAE.LAMBDA} will equal 1.00.

[dmaxfireman]

OK, so should I be using e0 to command a 14.68 afr or is using e10 with a commanded of 13.86 acceptable? I am still confused on how lambda is figured even though I understand what it means.

[joecar]

You have to edit B3601 to match the fuel you're using.


AFR is determined from stoich AFR and lambda (not the other way)...

i.e. lambda is universal across all fuels.

[dmaxfireman]

In the tune I uderstand that but what about my wideband controller (LC-1) How does it know that the stoich for the fuel I am currently running is 13.86 and not 14.7?

Sorry if i am not being specific enough or am missing the point completely, I just want to make sure I have all my ducks in a row before I go to try this again tomorrow. Just want to thank you again for all the help and time.

[joecar]

The LC-1 wideband controller measures Lambda (EXT.WO2LAM)...

and then for convenience it converts it to AFR (EXT.WO2AFR) based on the stoich AFR you programmed into your LC-1.


Since you're using EXT.WO2LAM for tuning (and not EXT.WO2AFR), you don't have to reprogram your LC-1


( the point here is: don't tune using AFR... use lambda instead... think in terms of lambda and EQR )

( it's easy, for NA: low load cruising lambda should be 1.00; high load (PE) lambda should be 0.85-0.86... i.e. you don't need to look at AFR )


Hey no worries, you're welcome :cheers:

[dmaxfireman]

Thanks Joe :)

Wish me luck, I'm gonna give her a shot again when I get home from work in the morning!

[joecar]

Let me know how it goes, post log files.

[dmaxfireman]

Well it looks like GM tuned it pretty good from the factory, I am all stock with a GMPP borla muffler. The Virtual VE table only changed a little and the VE coef table change under 3% after 4 short logs and adjustments. Not sure it is even worth messing with at this point. I have an increased throttle response and slightly increased midrange torque.

Should I be seeing much more than that with an all stock truck? #4 is what is currently in the truck with all settings back to normal except LTFT still turned off

[joecar]

I compared these two:
- CALC.BEN1_E38 (defined as {EXT.WO2AFR1}/{E38.AFRATIO_DMA}),
- CALC.WO2BEN (defined as {EXT.WO2LAM1}/{SAE.LAMBDA}),

in your logs they are giving different results (but are close to each other)...

I like the second one because it is independent of AFR

( the first one relies on two separate AFR's).

[joecar]

Are you trying to disable the MAF and run purely from VE...?

Did you fail the MAF...? If so, are you seeing a MAF DTC...? If not then ECM is not using VE.

You have set the MAF DTC's to Not-Reported (i.e. a MAF DTC will not trigger)... you want either of 1-Trip or Non-Emissions (and verify a MAF DTC appears immediately).

[joecar]

Is SAE.LAMBDA always 0.991 and E38.AFRATIO_DMA always 14.14...?

( when you enter PE mode, according to your tune file SAE.LAMBDA should go to 0.855 )

[joecar]

Your LTFT's are always zero...

look at B1510, it is disabling trims.

[dmaxfireman]

New day, new lesson learned!

I am using the lambda calculations for my BEN table so I am doing one thing right!

Going to have to go back and "fail the MAF" I thought that "not reported" would still do that when I pull the yellow wire out of the MAF plug. Start from scratch again.

[joecar]

The ECM uses both MAF (during steady state airmass) and VE (during transient airmass) if there are no MAF DTC's present.

The ECM uses VE only when a MAF DTC is present.


When the MAF DTC's are set to Not-Reported, they will never trigger (so you want to set them to either of 1-Trip or Non-Emissions, whichever one triggers immediately on startup).


When you see a MAF DTC present (Current) you can be absolutely certain that the ECM is now using VE.

[dmaxfireman]

Joe, I have not forgot about you, busy week with some family coming into town, as soon as I get another opportunity to play I will update this thread.

[joecar]

No worries, take your time, understand it, don't rush it.

:cheers: