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Im just looking for some quick clarification. Its a late 80’s Ford. Ive heard that on a Ford when you unplug the IAC it should drop the idle…a lot, to the point of loping or even stalling. When warm, my idle likes to be at around 1000…it needs to be at just above 600…..While running, i disconnect the IAC and BAM!!!!! no change at all. Am i correct in estimating there is an issue with the IAC?
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yea, i let it soak (just the valve) for a few seconds in 4-in1 cleaner…works as well with varnish and grime aas carb cleaner does, but doesnt destroy rubber…. made no difference :/
No vacuum leaks, the throttle plate closes fully and will even wedge closed when the throttle stop screw is too far out
It’s most likely stuck.
Remove it from the side of the air plenum and you’ll see two ports. Make sure they are not clogged up with carbon. If any carbon breaks off–it can get wedged into the valve.
While it’s removed, hose both ports on the IAC down with carb spray. I think you’ll find it’s either stuck, or something is wedged holding the valve part way open. If it’s just flat out stuck? The carb spray might not be good enough, in which case just replace it.
Another issue that people won’t think about–The throttle plate itself has a screw normally on the side to control things to some extent. If someone kicked that screw down and it’s holding the throttle plate open slightly, the IAC motor isn’t really being allowed to do it’s job. Sometimes backyard idiots…err…shade tree mechanics will just crank that screw down until it sounds “good” to them. (There’s a correct way to do things…..And by “ear” don’t cut it anymore)
(And yeah…I have the same setup on my Bronco II.)
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yea,my plate does close all the way, and the TPS does read out .95 volts, so the PCM isnt freaking out about it and over compensating…letting the valve soak didnt do much…a new entire IAC is only 50 bucks so its not too crucial
I’m cheap by nature. I can nip one up for $5 at the local pick and pull yard.
In reality, we solved a hard start issue with our truck. Turned out to be the coolant temp sensor for the computer itself was defective. Ford uses one for the gauge/light and another one for the computer. If that isn’t telling the ECU the correct temp, it will cause your engine to always run at the wrong idle. The CTS could be reporting the engine is always slightly under temp, so it runs the idle and such higher.
Just an idea…..
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Any Ideas are welcome!!! and i suppose that could be possible, i just never had the hard starting issue, starts on a dime every time :unsure: but yea, Theyre cheap at our UPAP so i might as well try both one after the other, just to see what the cause is….its not a horrible issue, just a mild annoyance really
I don’t always have good luck with cleaning IAC’s. In your case you might consider replacing it as many have suggested. I would also check the throttle cable tension. If it’s too tight it can open the throttle just enough to upset the idle. Lastly, be careful with your throttle body cleaning on those vintage Fords. Some of them had teflon coated throttle bodies that required a special cleaner to clean with. More info on solving idle issues here.
http://www.ericthecarguy.com/faq/solving-automotive-idle-problems
Keep us posted.
I totally removed it and put a sponge (makeshift filter) over the ports and played with it for a bit…if it was the butterfly valve or throttle cable then theoretically it would still idle if the port is closed right? i covered the intake port up totally and it did stall out…bubble by bubble 👿 anyways this just tells me that the IAC is stuck partially open…within the next few days im going to get a new one and i predict ill be good to go!!!!!!!!
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