IS COS3 for SD only?

[WeathermanShawn]

I have found I can understand many of the more detailed aspects of tuning, but sometimes I miss the more simple aspect of 'is this tuning parameter applicable to me'.

Car is a heavily modified 2002 Camaro Z-28, H/C 11.0:1 CR. Running a 2002 Operating system. Have already successfully AutoVESD, per the tutorial. Followed all the instructions, including disabling the MAF, etc.

I also re-calibrated the MAF. I then chose to return to a closed-loop tune (with MAF). This was for personal preference, and the car ran quite well.
I recently uploaded the COS3 operating system. My question pertains to table B3647 (Commanded fuel vs RPM).

Was I supposed to disable the MAF in order to get consistent AFR's?

Though I spent a lot of time attempting to perfect table A0014 (IAT VE Multiplier), I was never able to achieve consistent AFR's. I did keep the MAF enabled.

Did, I miss the obvious?

[TAQuickness]

COS3 can be used with MAF. B3647 gives you finer control of the open loop fueling.

[WeathermanShawn]

Thanks TA.

What was concerning me, was that while COS3 allows you to command your fuel level to a much greater extent, isn't it relying on your VE table for airflow?

This question pertains only to the non-14.63 commanded cells. Are you saying that in COS3 open loop, your commanded fuel is determined by both MAF and VE? Even though it is not in closed loop in those cells?

I'll keep trying, but every day brings a new AFR..unlike closed loop.

I'll keep working on A0014.

Anybody else use COS3, with MAF?

[redhardsupra]

no, MAF and VE determine airmass, fueling is regulated by the commanded fuel, all its modifiers, and then the injector flow model. open loop has NOTHING to do with MAF or VE.

[joecar]

1. MAF or SD (MAF-less),
2. CL or OL,


#1 and #2 are orthogonal and independent of each other (i.e. there are 4 combinations).


#1 determines airmass; MAF uses MAF and VE depending on B0120; SD uses VE.

#2 determines AFR; CL uses feedback to trim to stoich; OL uses B3647/B3605/B3618.


PCM uses #1 and #2 to determine fuelmass, and then uses B4001 to determine pulse width.

[WeathermanShawn]

Thanks for all the replies.

So, Joecar the airmass calculation (MAF & VE) using COS3 semi-open loop is exactly the same as utilizing the CL function found in the 'normal' operating system (2002 OS)?

If I understand your point, other than the trimming differences of CL, the airmass calculation is identical to what one can choose using the 'standard' operating system? Obviously, utilizing the same B0120 parameter.

Is the AFR inconsistently all in your ability to accurately determine A0014?

Thanks for your patience. I know it is not always easy explaining these concepts. I am just seeing more variability in AFR's than I expected.

[joecar]

SOL uses STFT's whereas CL uses LTFT's.