gm.trqeng

[dian]

99 c5. what are the inputs for torque in a stock tune? what happens if you loose the maf? and how is it with cos3 and (e.g.) a 2bar map?

(gm.trqeng seems to yield same values as gm.trqtrans. any thoughts on that?)

edit: this is what im seeing at 200kpa/no maf. (i cant upload scan for some reason.) rising ibpw to redline, dyncylair rising to redline (1.90 max), torque peaking at 3800* with a (quite realistic for max) value around 800 nm, acceleration fluctuating but highest at 5000-6000, calc.power rising to redline with 500 rwhp max (not unrealistic, a bit low). in a stock cofiguration i see max torque at 450 nm (engine rating is 475).

*140kpa

[nonnieselman]

Ive never tuned a MAF for boost so i have no idea on this one.

[joecar]

GM.TRQENG and GM.TRQTRANS should read the same for combined engine/trans PCM.

[dian]

maf is gone.

so are you saying the ecu looks at map and iat only to calculate torque/dyncylair? (obviously it understands boost wit cos3.) how does it then happen it thinks they are highest at low rpm/bosst (3800/140kpa)? iat* is the same and i surely do not have the largest v/e numbers in the midrange, they are rising up to redline.. a stock car reports highers tq/cylair around 5000 btw.

*in both cases maf would be well beyond the 120g/s blending table limit

[joecar]

Are you getting a MAF DTC...?

[joecar]

ECU first calculates airmass using MAF and/or VE, it then calculates everything else, including fuel mass and ignition advance.

[dian]

dtc has been programmed out for 7 years now.

so no thoughts on what im seeing?

[joecar]

Without MAF DTC, ECM is using both MAF and VE at different times/conditions.

[joecar]

You can program MAF DTC's to not light up the MIL when the DTC is present, but this is not the same as disabling the MAF DTC's

[joecar]

ECM ignores MAF only if MAF DTC shows up.