fyi
March 17th, 2006, 12:15 PM
I give up....I've tried everything and I don't give up easily.
2002 C5 Corvette A4
427 Vortech T-trim S/C
236/242 115
Mototron 60 lb/hr
FAST fuel rails
Aeromotive FPR
Racetronix pump/fuel system
1997-98 fuel system
SS3200
3.42 gear
Headers, cats, etc, etc, etc.
Idles at 875 RPM, 50 MAP in park- 65 MAP in gear, Idle timing 21*, approx. 3500-3700 mhz MAF at idle, FTC 17 at idle. (more info if needed)
Tuned the calibration w/ RoadRunner, BEN's are at .9 or 1.0 across the board, MAF curved adjusted 11% positive to account for error, -2.5% to -3.3% o2 correction everywhere, idles smooth, added 6% to injector offset to correct error, used online calculator on this site to adjust IFR.
The car runs *excellent* in every-single area of the powerband and the calibration appears to be spot-on according to my logs, except at idle. No matter what I do, I cannot get the LTFT to come down from +11% at idle and it's driving me nuts.. I've even went as far as making HUGE adjustments to fueling in that area just to see if it made a difference, but it doesn't!
The o2's are new, there are no leaks with the A.I.R. system, (new check valves both sides) the headers are new, the engine is new and sound... I've built similar cars like this before and *NONE* of them gave me this kind of problem...
I'm completely out of answers, have tried everything under the sun I know of and haven't a clue of where to do next... :nixweiss:
Maybe LTFT boundry MAP/RPM change?
Anyone like to take a stab at it to help please?
2002 C5 Corvette A4
427 Vortech T-trim S/C
236/242 115
Mototron 60 lb/hr
FAST fuel rails
Aeromotive FPR
Racetronix pump/fuel system
1997-98 fuel system
SS3200
3.42 gear
Headers, cats, etc, etc, etc.
Idles at 875 RPM, 50 MAP in park- 65 MAP in gear, Idle timing 21*, approx. 3500-3700 mhz MAF at idle, FTC 17 at idle. (more info if needed)
Tuned the calibration w/ RoadRunner, BEN's are at .9 or 1.0 across the board, MAF curved adjusted 11% positive to account for error, -2.5% to -3.3% o2 correction everywhere, idles smooth, added 6% to injector offset to correct error, used online calculator on this site to adjust IFR.
The car runs *excellent* in every-single area of the powerband and the calibration appears to be spot-on according to my logs, except at idle. No matter what I do, I cannot get the LTFT to come down from +11% at idle and it's driving me nuts.. I've even went as far as making HUGE adjustments to fueling in that area just to see if it made a difference, but it doesn't!
The o2's are new, there are no leaks with the A.I.R. system, (new check valves both sides) the headers are new, the engine is new and sound... I've built similar cars like this before and *NONE* of them gave me this kind of problem...
I'm completely out of answers, have tried everything under the sun I know of and haven't a clue of where to do next... :nixweiss:
Maybe LTFT boundry MAP/RPM change?
Anyone like to take a stab at it to help please?