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Guest Message by DevFuse

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Just replaced heads, now funny idle?

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5 replies to this topic

#1 Ditch64


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Posted 17 February 2014 - 04:44 PM

Car: 98 Impreza Outback Sport 2.2


Hey guys, I recently had the timing belt tensioner pull out, threads and all, dropping the timing belt, causing the valves to smash into the pistons. So, I pulled the car apart, went to the local pick and pull, found a 93 legacy with a 2.2 gen 1 with dual port heads. Said screw it, grabbed them, and the header, slapped it all together with all new gaskets etc... Now the problem I am having is, when the car is warm, not only when hot, just even luke warm or having been started a few hours ago, enough to not cause the idle to raise due to it being cold outside, right after initial start, it will die. If I rev it up a little (1-2 seconds) after starting, it'll come back down to proper idle, as it should.  I am also noticing the idle being a LITTLE low normally. So, as long as I just give it a little rev after starting, it'll idle fine (smooth) for however long the car is running for, stop lights, whatever, no problem.  It didn't do this whatsoever before swapping heads, so maybe one of you guys could throw me a bone here as to what it could be. I have NO vacuum leaks, new PCV hoses, and a new air filter. The only think I can think is, it's mad at me for going from single port heads to dual port heads?? I have no idea.  Other then the start up idle issue, the car runs GREAT!


Thanks guys,



Oh, just for fun, I should add that the car has 248k on it, and when I had the heads off, I examined the cylinder walls, and the top of the pistons. The cylinder walls were IMMACULATE, no scoring, beautiful crosshatching, and the top of the pistons had a LOT of carbon build up, which I cleaned up a little. 

Edited by Ditch64, 17 February 2014 - 04:52 PM.

#2 pocketxgirl


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Posted 18 February 2014 - 01:11 AM

Have you tried cleaning the IACV?

#3 Fairtax4me



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Posted 18 February 2014 - 02:30 AM

Reset the computer by unhooking the battery negative for about 10 minutes.
When you hook it back up start the engine and let it figure itself out. DO NOT press the throttle to keep the engine running. If it stalls, turn the key off, then restart the engine. Do not touch the throttle. Let the computer figure out proper base idle fuel setting. Once it has warmed up and the fans cycle once, turn it off, restart, then go for a drive.

The cams in the heads you bought have a different profile than the cams from your stock heads and the computer will need to re-adjust for proper air/fuel settings to match those cams. Resetting the ECU should allow it to re-learn its base settings and it should be fine after.

Edited by Fairtax4me, 18 February 2014 - 02:34 AM.

#4 ivans imports

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Posted 18 February 2014 - 10:25 AM

The real diff is one is solid valve train one is hydro valve train I did the same swap last week no problems but ticked and ran funny till lifters pumped up took 40 of running is normal for the hydro lifter heads to take a while to find there valve adjustment did you remove the lifter blocks from heads ?

#5 Ditch64


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Posted 18 February 2014 - 12:13 PM

Thanks guys, I'll go reset it when I get back from school. 


Also, the IAC was cleaned a few months ago.


And I never took the heads apart, just replaced the valve cover gaskets, and any other mis gaskets. 

#6 ivans imports

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Posted 19 February 2014 - 10:58 AM

Check engine light on ?

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