Got a 93 Z-28 M6 that wants to lean out when the ambient temperature gets above 55 degrees F. Colder it gets the better it likes it. It has a new fuel pump, Opti is in good shape and no codes.
Any ideas?
Tom
Any ideas?
Tom
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botched Custom programing, exhaust leak before o2 sensor, o2 sensor/s bad, bad injector/s. Is the charging system good, batt and alt. working at peak preformance. bad or weak injectors may not be pumping enough fuel at higher RPMs, fuel presure regulator may be going bad check FP at the fuel rail. Check vacume lines going to the FPR to make sure FPR is working properly.
Eric W.
89 Firebird Formula WS6
Accel/Lingenfelter Super Ram
6.2L/382.97 ci
Custom PROM Dyno tuned
WCT-5 speed
BW 9-bolt Posi 3.45
Boss MS 18" Rims
Headman Headers 1 5/8 Ceramic Coated
Custom Dual exhaust
1LE upgrade
Custom Temperature / Navigation Rear View Mirror
In a constant state of upgrade!
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Intake Air Temp sensor? It's the only think I can think of that would be affected directly by the ambiant air temp. Everything elso will warm up to operating temperatures no matter what the outside temp is that day.Tracy
2002 C5 M6 Convertible
1994 Z28 M6 Convertible
Current Mods:
SLP Ultra-Z functional ramair, SS Spoiler, STB, SFCs, Headers, Clutch, Bilstein Shocks, and TB Airfoil. 17x9 SS rims with Goodyear tires, 160F T-Stat, MSD Blaster Coil, Taylor wires, Hurst billet shifter, Borla catback with QTP e-cutout, Tuned PCM, 1LE Swaybars, 1LE driveshaft, ES bushings, White gauges, C5 front brakes, !CAGS, Bose/Soundstream audio, CST leather interior, synthetic fluids
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How do you know it's leaning out?? Have you watched it on a scanner???Comment
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Same question as above... how do you know its leaning out? Under what conditions is it leaning out - idle, part load/closed loop, full-throttle/power enrichment mode?
Since you have a speed density detup, the IAT and MAP sensors are critical to the A/F calculation. Have you verified the accuracy of both these? You running the 4.4Kohm resistor in the IAT socket?Fred
381ci all-forged stroker - 10.8:1 - CNC LT4 heads/intake - CC solid roller - MoTeC engine management - 8 LS1 coils - 58mm TB - 78# injectors - 300-shot dry nitrous - TH400 - Gear Vendor O/D - Strange 12-bolt - 4.11's - AS&M headers - duals - Corbeau seat - AutoMeter gauges - roll bar - Spohn suspension - QA1 shocks - a few other odds 'n ends. 800HP/800lb-ft at the flywheel, on a 300-shot. 11.5 @ 117MPH straight motorComment
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More information
The car has 177k miles, virtually original. We have replaced the Opti three times. It has new O2 sensors, no exhaust leaks and a new fuel pump. No SES indications.
When the ambient temperature is above 60 deg F, the engine will lose power intermittently - single cylinder. At full throttle, it will pull strong to redline.
Below 60 deg F, the car will loose power before reaching operating temperature but after that it runs without hesitation. This engine has always responded to cold air but now the lean out is much worse.
Yes, it is lean, just like when you run out of gas. No backfiring. When you cannot smell the exhaust from an LT-1 it is lean and that is the condition that we have.Comment
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