Open loop on deceleration

[hpcubed]

I notice that my long term fuel trims always go negative (-8 - -12) when the throttle is closed and the car is moving. I notice that my maximum throttle position for idle long term fuel trims is set for 1.19. But my minimum throttle position at idle is about 6.7% could this be a culprit? Or look elseware?

[wait4me]

looks like you have passed the amount of tps that the car can correct for. You probably opened up your throttle blade too much. When you guys turn the throttle blade up instead of drilling a hole, you have only a certain amount of turns before the car can no longer correct the starting tps %. So if you hit the point, Not drilling the throttle blade is not an option. You have to drill the Throttle blade and then turn the throttle blade for fine adjustments to get your steps inline.. :) so you have to back it out till it says 0 tps, then drill the blade to make up the difference..

[bink]

I notice that my long term fuel trims always go negative (-8 - -12) when the throttle is closed and the car is moving. I notice that my maximum throttle position for idle long term fuel trims is set for 1.19. But my minimum throttle position at idle is about 6.7% could this be a culprit? Or look elseware?

FRC- C5/ETC (Fly by wire). Do the LTFTs actually update the PCM in a decel cell (20 or 21)? I didn't think they updated?

[jfpilla]

I notice that my long term fuel trims always go negative (-8 - -12) when the throttle is closed and the car is moving. I notice that my maximum throttle position for idle long term fuel trims is set for 1.19. But my minimum throttle position at idle is about 6.7% could this be a culprit? Or look elseware?

FRC- C5/ETC (Fly by wire). Do the LTFTs actually update the PCM in a decel cell (20 or 21)? I didn't think they updated?

What cells are you in when you see the -8 to -12? Often cells 5 and 6 or thereabout, need VE adjustment to bring them in line with the rest and then use IFR's or MAF to bring all into line.

Joel,
I don't think they do. But in my car I never see 21 and only see 20 before the 02's are reporting.
Joe