New IAC problems.

88 Fox GT

Active Member
Nov 18, 2002
1,674
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Iowa
I had a new(er) IAC sitting in my garage that I got at a salvage yard. The insides are very clean, and it appears to be one that someone bought at a parts store. It's not an original Ford IAC. Well, the solenoid (or whatever it's called) on it had the connector in the wrong position, so I took my original solenoid and bolted it onto the body of the new IAC. Well, now my idle is WAY too high most of the time. When you start it up it will idle up to around 1500rpms and then slowly drop just like it should. But, after driving down the highway a little bit, push in the clutch and the thing revs out to 2000-2200 RPMs. Also has crappy engine braking because of this. I came home tonight and put it in nuetral in my driveway and it just sat there idling at 2k. I have reset the computer twice. I just don't know how long it could possibly take for the computer to adapt to this new IAC. What I think the problem might be is that it's used to an old, gunked up IAC and it's pushing the plunger open further to compensate for the gunk. Well, with a clean IAC I think it might be opening it too far? Am I correct on my thinking?
So, how long do you think it will take for this thing to adapt and idle where it should?

Also, aren't the sensor and actuator baselines stored in the Keep Alive Memory (KAM) of the EEC-IV? If so, the thing should have adjusted (for most of the part) as soon as the battery was reconnected and the key was turned on, correct?
 
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I know you are tired of seeing my useless posts on your threads, but here goes. :)

I like your thinking. Clearing the KAM should have averted many issues as the puter learned to trim the duty cycle of the new IAC (since the new one is so effective at lesser dwells).

I will note that some aftermarket (parts store) IAC's have instructions saying to install them upside down. I wonder if this is the case for you. I have not used one, but *I think* people have reported a high idle if they did not install it upside down (not sure how they mounted it though - it sounds like it wont fit 'right-side up').

Good luck with it.
 
It looks exactly like Ford IACs, just doesn't have "Ford" printed on it anywhere, just a part number. I suppose I could try installing it upside down. I wonder if it would fit? lol
 
if it looks like your old one, I might leave well enough alone. when you mentioned having to modify it, my first thought was that it was 'an upside down' one. Sounds like this is not so. :)
 
I'll see how installing it upside down works out. If it doesn't do anything, I will keep driving it for maybe a week or so to see if it finally adjusts. My F150 idled high when I installed a new IAC on it. But, all I had to do to it was unhook the battery for 20-30 mins to reset the computer.

Thanks. :)