1988 Regal Fiasco Many Sensor & Electrical Problems
#62
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my inlaws car seems to be having a similar problem, and im not quite sure what it is at this point, i thought it was the iac but since you replaced your now im not so sure. i think in your case if you adjust the idle screw it maybe just bypassing the iac, havent done many obd1 vehicles but i dont think they even have one on the newer vehicles
#63
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I'm torn between:
1) if I adjust the low idle screw, I'm ignoring the real problem - maybe transmission control related.
2) if I don't adjust it, I'm ignoring the correct procedure after working on the Throttle Body.
I think in my and your case, maybe drive it for awhile to see what'* up. It seems like both are intermittents and I don't have a SES light after fixing the vacuum snafu.
1) if I adjust the low idle screw, I'm ignoring the real problem - maybe transmission control related.
2) if I don't adjust it, I'm ignoring the correct procedure after working on the Throttle Body.
I think in my and your case, maybe drive it for awhile to see what'* up. It seems like both are intermittents and I don't have a SES light after fixing the vacuum snafu.
#66
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Yes, I agree. What I'm starting to think is, when the car is shut off, the IAC motor is set for the next re/starting position. If it is sticking when retracted due to age or dirt, when starting in closed loop again, I guess the only feedback for the ECM to readjust it is when the TPS sensor value changes like when we have to press the pedal or maybe O2 or other sensor gives adequate feedback. It'* a brainteaser for sure. Did the scanner show the right TPS voltage at closed throttle - I don't remember what you wrote.
#67
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Yes, I agree. What I'm starting to think is, when the car is shut off, the IAC motor is set for the next re/starting position. If it is sticking when retracted due to age or dirt, when starting in closed loop again, I guess the only feedback for the ECM to readjust it is when the TPS sensor value changes like when we have to press the pedal or maybe O2 or other sensor gives adequate feedback. It'* a brainteaser for sure. Did the scanner show the right TPS voltage at closed throttle - I don't remember what you wrote.
#68
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on my Father inlaws buick the throttle position was 0 when off the throttle then any little movement on the petal would show an increase on the scanner
#69
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Assuming on a deal like this, there are no spark/ignition related problems, then either (and since your sensors scan OK):
1) Too much/too little air through the IAC port at start-up - in relation to fuel delivery.
2) EGR valve going bad.
3) Too little fuel delivery at start-up via the ECM thinking it'* flooded.
The rough Idle at start up and needing to give it gas sounds like the vacuum problem I was struggling with, but mine did it at every start-up for the most part.
1) Too much/too little air through the IAC port at start-up - in relation to fuel delivery.
2) EGR valve going bad.
3) Too little fuel delivery at start-up via the ECM thinking it'* flooded.
The rough Idle at start up and needing to give it gas sounds like the vacuum problem I was struggling with, but mine did it at every start-up for the most part.
#70
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True Car Nut
1)thats what i think is going on
2)on a 2000 the egr codes are oversensitive so if it was bad i would think it would set a code. there are no codes set either.
3) not sure how you would check that other than i checked maf, temp(air+coolant)sensor readings, fuel pressure, fuel trims, seems all normal
2)on a 2000 the egr codes are oversensitive so if it was bad i would think it would set a code. there are no codes set either.
3) not sure how you would check that other than i checked maf, temp(air+coolant)sensor readings, fuel pressure, fuel trims, seems all normal