Can't figure it out
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New User
Joined: Dec 2001
Posts: 22
Likes: 0
Can't figure it out
My BII is doing something very strange and to date two different dealers can't figure it out.
At idle with the A/C on the vehicle runs fine, smooth with the A/C cycling on and off.
But if the A/C is turned off, the idle goes bad. It stays steady at about 1000 rpm then drops to 600 almost stalls and move up back to 1000 rpm. This cycle never ends. You can even put a watch on the this crazy idle - about 1 minute. The only thing that affecst it worse is turning on the lights.
I've kept this vehicle up to specs with regular maintenance. The dealers checked the vehicle up and down with no luck.
Any ideas welcomed.
At idle with the A/C on the vehicle runs fine, smooth with the A/C cycling on and off.
But if the A/C is turned off, the idle goes bad. It stays steady at about 1000 rpm then drops to 600 almost stalls and move up back to 1000 rpm. This cycle never ends. You can even put a watch on the this crazy idle - about 1 minute. The only thing that affecst it worse is turning on the lights.
I've kept this vehicle up to specs with regular maintenance. The dealers checked the vehicle up and down with no luck.
Any ideas welcomed.
Post Fiend
Joined: Jun 2002
Posts: 13,873
Likes: 3
From: Atlanta GA
Can't figure it out
I would tend to think the IAC is bad or needs to be cleaned. It is a long aluminum solenoid on the right side of the engine. It might be a throttle position sensor, but, my reason for the IAC is this (been a few years since I read the Ford EEC-IV book).
When the A/C is on, the engine gets automatically kicked up to a preset idle speed when the speed and TPS are read. When the A/C is off, the IAC (Idle Air Control) is factored instead. Since it has not shown up bad on a code read, I would tend to think it is dirty and the intake needs to be cleaned too. It can be loaded up with carbon and still test good, but, give an inaccurate reading back to the CPU.
When the A/C is on, the engine gets automatically kicked up to a preset idle speed when the speed and TPS are read. When the A/C is off, the IAC (Idle Air Control) is factored instead. Since it has not shown up bad on a code read, I would tend to think it is dirty and the intake needs to be cleaned too. It can be loaded up with carbon and still test good, but, give an inaccurate reading back to the CPU.
