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AC kills engine at stop lights.


csgt428

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Hi, I'm new here. I just bought an 86 BII XLT 5-sp. THe PO told me the AC works fine driving down the road but kills the engine at stop lights. Is there some kind of sensor that isn't kicking up the idle rpm w AC on?
 


Uncle Gump

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You have a 2.9.L I presume?

Idle speed is controlled by the computer using the IAC actuator to bypass or not bypass air past the throttle plate. The more air that is bypassed... the higher the idle speed.

Does the engine start up cold with a higher rpm and then lower itself to idle once warmed up?
 
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csgt428

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You have a 2.9.L I presume?

Idle speed is controlled by the computer using the IAC actuator to bypass or not bypass air past the throttle plate. The more air that is bypassed... the higher the idle speed.

Does the engine start up cold with a higher rpm and then lower itself to idle once warmed up?
Yes I do and yes it does. Cold idle works perfectly.
 

tw205

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Hi, I'm new here. I just bought an 86 BII XLT 5-sp. THe PO told me the AC works fine driving down the road but kills the engine at stop lights. Is there some kind of sensor that isn't kicking up the idle rpm w AC on?
Has this happened while you were driving or in the car? If it hasn’t, then maybe you're tryin to fix something that ain’t broke.
 

csgt428

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Has this happened while you were driving or in the car? If it hasn’t, then maybe you're tryin to fix something that ain’t broke.
Sort of, I turned on the AC and the engine slowed down and almost quit a couple times and running very unevenly, pretty sure it would have quit if I had left it on longer. That being said I will wait till it kills engine the next test.
 

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