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My IACV keeps giving me problems

Posted: Tue Apr 29, 2014 10:57 pm
by rallyak
I've cleaned it dozens of times which helped but now it won't idle lower than 1200 rpms at lights. My CEL comes on throwing code 24 and sometimes when I start it runs really ruff like a misfire, always when it's hot but still idles at 1200 rpm's. Of course mine is a 90 5spd and they only put those on 90-91 5spd so finding a used one is difficult.

Things that I've done in the past to help the problem is:

Adjusted the idle down (I know not to touch the factory settings) till the throttle valve is completely shut and put a restrictor in the hose going to the intake pipe. That's help a lot at start up in the morning (w/out restriction it runs at 3500 rpm's when cold with restriction 2000 rpm's)

After the idle was adjusted down when it warm it use to idle at 850 rpm's but that was two years ago. It keeps creeping up and now I don't have any more tricks to throw at it.

I've ordered a new IAC from Subaru today to try to fix this problem and the price wasn't bad 124$. If any one has any suggestions or any other tricks let me know.

Re: My IACV keeps giving me problems

Posted: Thu May 01, 2014 12:02 am
by lucas
I posted a video a while back of a dude with the same problem, and he showed a good way of "cleaning" it. I have the exact same problem you do ive just accepted its a fact of life for old legacies. I managed to lessen the occurances of the IACV acting up on my car with routien stuff. Plugs Good wires, PCV, Coolant temp sensor. and fixed a few split wires on some sensor pig tails. Let us know how the new valve works out and man you got a cheap price.

Re: My IACV keeps giving me problems

Posted: Thu May 01, 2014 2:21 am
by rallyak
It's defiantly frustrating, I use ngk plugs and wires coolant sensor is fairly new and PCV has been replaced. The car runs great starts in -70 temp with no problems. I believe I cleanest IAC on the board. I seafoam it every oil change in the winter and in the summer I remove it to clean it. It's never very dirty but yet it keeps climbing. I posted a pic in my journal of one of my cleanings in the snow. I hope the new IAC fixes it, I will let you know.

Re: My IACV keeps giving me problems

Posted: Thu May 01, 2014 4:02 pm
by wtdash
Something I've noticed on my car is if I just replaced the top piece which is interchangeable with almost all the 2.2 and 2.5 IACs it'll help with that idle issue - it doesn't fix the coldstart issue with EJ 20 ECU - but it does help with the idle. good luck w/the new one.
And where did u get it for $124?

TD

Re: My IACV keeps giving me problems

Posted: Thu May 01, 2014 4:54 pm
by rallyak
I don't think the top piece on mine is interchangeable with others, mine is two pin and and just a solenoid that goes up and down. I know my wife's is a different design, hers spins and adjustable I believe that is the common one. I'm getting my new one from my local subaru dealer, I hope he ordered the correct one but he did match it up with my vin.

Re: My IACV keeps giving me problems

Posted: Thu May 01, 2014 10:25 pm
by wtdash
That part is close to $300 on other sites....but if it's for the '90 may be it's different??

Re: My IACV keeps giving me problems

Posted: Thu May 01, 2014 11:33 pm
by lucas
I know the price is crazy, wish it was the same for my 93 ss. IACV imo is the most dumb idiot thing on any car ever. I have a 93 S10 that has IACV problems too......................... must have just been 90's stuff.

Re: My IACV keeps giving me problems

Posted: Fri May 02, 2014 12:02 am
by rallyak
It's basically a controlled vacuum leak, I think it dumb also.

Re: My IACV keeps giving me problems

Posted: Fri May 02, 2014 5:26 am
by lucas
i wish i could just block it off and not have more problems.

Re: My IACV keeps giving me problems

Posted: Fri May 02, 2014 5:27 pm
by Legacy777
If you are getting a code for the IAC valve, than the actual solenoid part of the valve is probably what's bad and not the valve itself. There's no cleaning you can do to fix the solenoid. I would suspect the new valve should fix your problem.

Re: My IACV keeps giving me problems

Posted: Mon May 12, 2014 11:23 pm
by rallyak
Well Subaru ordered the wrong part, it was the purge solenoid. I knew it was to good to be true. They checked the correct part # and guess what.... Discontinued. So I went digging through my parts and found a two pin IAC, but I remembered installing that one on my car and didn't work, the idle was way to high. So I took the solenoid off the top and the one on mine and found the spare was missing a spring. I install the new solenoid and all is good now. I don't think my IAC has ever worked properly since I've own it.

Re: My IACV keeps giving me problems

Posted: Wed May 14, 2014 3:30 am
by lucas
Right on man!! Glad it all worked out.

Re: My IACV keeps giving me problems

Posted: Tue Sep 09, 2014 1:01 am
by jessman1942
thread from the dead im gonna try this on my ej20g swap iv been having erratic iac issues aswell wish me luck

Re: My IACV keeps giving me problems

Posted: Thu Sep 11, 2014 6:05 pm
by lucas
good luck man I've had IACV problems for 6+ years

Re: My IACV keeps giving me problems

Posted: Sat Sep 20, 2014 7:45 pm
by oldscoobyturbo
i've swapped the top part on my swapped car and its solved the warm idle issues. The 20g ecus don't like the cold/cold starts