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Firebird RPM while idling

What is the recommended/best RPM when the car is idling or in park? I got a 1994 Pontiac Firebird (3.4 V6, automatic) and after I had my AC recharged, it's idling at around 1500 RPM, it used to idle at about 800 RPM. The mechanic said that the "computer is re-learning how to handle the AC and that I need to drive the car for a few miles". Is he right? How many miles is "a few miles". Is the car in any danger?

I also had one of the hoses (the one that goes from the right side of the radiator, near where the air filter is, to wherever) replaced because it had a leak. Is it possible that the problem lies there?

(sorry for the cross-posting, I value the usenet groups and I want to peek as many brains as possible).

Thanks in advance.

Reply to
darkeddie
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He is not correct. In the days before computer controlled engines, the idle needed to be set a bit higher to allow for generator/alternator load. When the AC was turned on the idle speed was increased to take care of its extra load. Today the micro processor adjust the fuel/air ratio to take care of the additional load, or the removal of load, and the idle speed does not change.. The idle therefore need only be around 700/800 RPMs

mike hunt

Reply to
Mike Hunter

That's wrong on every computer controlled fuel injection car I've ever worked on. The computer controls idle speed by bypassing air around the throttle plate to increase or decrease idle speed as a function of load. The O2 sensor input to the ECM goes slightly lean due to the increase of air from the idle air control circuit, and correspondingly increases injector pulse with slightly. Or decreases pulse width when the load is removed and the IAC circuit provides less air. That is an accurate representation of the operation. You can see this happen with a Genesys scanner very easily.

Reply to
Garrett Fulton

What part of; 'Today the micro processor adjust the fuel/air ratio to take care of the additional load, or the removal of load,' did you not underatnd? ;)

mike hunt

Reply to
Mike Hunter

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