idle ac problem

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Jun 25, 2008 | 12:19 AM

gbrewer

Thread Starter

Junior User

Joined: Feb 2008

Posts: 58

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From: Fairfield oh

idle ac problem

I have an 87 f150 4.9l, just bought less than 1 yr ago, the previous owner had disconnected the power from the ac compressor. I dont know why. Any idea why it was disconnected. What is a reason for disconnecting ac compressor? I plugged it back in, but no cold air. Refilled ac with freon, now it provides cool air. BUT it stalls easier when first started. It used to rev higher when started then slow down gradually. Now it starts out lower rpm and stalls easily. Runs fine after started 2nd or 3rd attempt. I've read some about IAC valve. Could this be the problem? If so how do you clean it out or does it have to be replaced.

Jun 25, 2008 | 08:23 AM

Conanski

FTE Legend

Joined: Jun 2006

Posts: 31,930

Likes: 1,499

From: Ottawa, Ontario

The IAC is on the side of the throttlebody, it's the long cylinder like thing. These can be cleaned somewhat by spraying some carb cleaner into the ports while the engine is running, but taking it off and soaking it overnight will do a better job.

Doe your AC clutch cycle? Meaning can you hear it engage and disengage every minute or so as the motor runs? If it stays engaged all the time the clutch may be bad or the pressure switch is bad/disconnected, it's on the coolant line over near the air box. The compressor puts quite a load on the motor and it should not be engaged when the motor starts, if it is this will make it stall in many cases.