removing or cleaning IACV and Throttle body? - Subaru Outback - Subaru Outback Forums
 
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post #1 of 10 (permalink) Old 07-31-2007, 02:54 PM Thread Starter
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removing or cleaning IACV and Throttle body?

so the mechanics have diagnosed my IACV as my problem for high idling. $435 is the estimate.

I plan to try the full cleaning, remove and scrub everything. they said they did the TB cleaner in the PCV last time, and since it started acting up again after just a couple months, they said it was time to replace the IACV.

so. can I replace maybe just the motor on the butterfly valve while I'm at this? or is it the whole job or nothing?

also, do I need a new gasket if I pull the TB? I did many searches, and there were a lot of "I don't pull it just to clean it" comments, but I think it really needs a good one... someone mentioned really getting into the IAC motor which I think does need it...

I got the link to the endwrench.com article on IAC cleaning.

I haven't gotten any CEL warnings, just a high idle and rough engine braking. replaced the PCV and it was dirty, but still working I think.

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post #2 of 10 (permalink) Old 07-31-2007, 03:42 PM
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Hi. Is this on the '97 Impreza? If so, the IACV is not mounted on the throttle body. It is sort of down below the PCV valve. I have a pic pointing it out if desired. TB cleaner in the PCV would not clean the IACV.

The intake hose to the IACV needs to be pulled, and then at idle give it shots of throttle body cleaner right in there. Just a quick shot at a time so the engine doesn't kill but just sputters. I would definitely try this since it will only take a few minutes and a couple $.

If the throttle body or IACV are removed, yes, the gaskets should be replaced. Are they sure you don't have any vacuum leaks? This can cause high idle too.
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post #3 of 10 (permalink) Old 07-31-2007, 11:05 PM
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Sea Foam to the Rescue = Another Cheap Fix

Stick some Sea Foam in first, before you give all your money away to the third party. You can pull the hose from the PCV and put some directly in the PCV. Sea Foam the induction by allowing the Sea Foam to be vacuumed into the intake manifold on the hose you just disconnected from the PCV which is connected directly to the intake manifold. Other than pulling the hose off the PCV you won't have to disassemble anything else and in short order will find out you just might have the entire problem licked. Read up on all the Sea Foam links.
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post #4 of 10 (permalink) Old 08-01-2007, 08:09 AM
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A good seafoaming does usually give good results. If you do that, you still need to clean the IACV as sucking seafoam or any cleaner through a vacuum line will not touch the IACV.
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post #5 of 10 (permalink) Old 04-05-2010, 10:01 PM
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Quote:
Originally posted by porcupine73
A good seafoaming does usually give good results. If you do that, you still need to clean the IACV as sucking seafoam or any cleaner through a vacuum line will not touch the IACV.
I believe there are two hoses that connect to the IACV... one big one and one small one... which do we pull?

Once the hose is pulled... spray directly into the IACV?

Thanks,
Andre

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post #6 of 10 (permalink) Old 04-05-2010, 10:25 PM
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I would disconnect the big one. That is the one for the air intake. The smaller hose is for the coolant flow to prevent icing in the unit during low temp operation. If it's a '98 it has the MAF style setup; sometimes they can be finicky about idling with the IACV air intake hose unhooked. In those cases I just unplug the MAF while I am spraying in the cleaner. If you spray too much cleaner it will stall out. So usually I just give it quick bursts and let it sputter a bit and then when it recovers give it some more.
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post #7 of 10 (permalink) Old 04-05-2010, 10:28 PM
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It will still start typically if the timing is off a tooth. On that DOHC getting the timing all bang on with all four cams and the crank is a little tricky. If a non-Subaru familiar shop did the work it is possible the timing is off a tooth. Sometimes doing a compression test will reveal it.
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post #8 of 10 (permalink) Old 04-05-2010, 11:01 PM
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Quote:
Originally posted by porcupine73
I would disconnect the big one. That is the one for the air intake. The smaller hose is for the coolant flow to prevent icing in the unit during low temp operation. If it's a '98 it has the MAF style setup; sometimes they can be finicky about idling with the IACV air intake hose unhooked. In those cases I just unplug the MAF while I am spraying in the cleaner. If you spray too much cleaner it will stall out. So usually I just give it quick bursts and let it sputter a bit and then when it recovers give it some more.
Cool... I'll have to give it a shot the next weekend.

Andre

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post #9 of 10 (permalink) Old 04-05-2010, 11:05 PM
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Quote:
Originally posted by porcupine73
It will still start typically if the timing is off a tooth. On that DOHC getting the timing all bang on with all four cams and the crank is a little tricky. If a non-Subaru familiar shop did the work it is possible the timing is off a tooth. Sometimes doing a compression test will reveal it.
Yeah... it starts perfect and the idle (550 RPM) is normal (meaning no spuddering or anything)... it's just that annoying shake that it has now. I didn't do a compression test but I did hook up a vacuum gauge and the reading was around 20" +/-0.2". I think if the timing was off, I think the needle would make some drastic changes, but then again I wouldn't know that... just assuming so. Oh... and also got great gas mileage on the way home as well from the shop... so idk... maybe I'm just overreacting.

I was doing some research outside of these forums and it seems that the shake at idle is a common thing with a boxer engine. Most actually seem to admit having it while only a select few say they don't.

Andre

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post #10 of 10 (permalink) Old 04-05-2010, 11:18 PM
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Shake At Idle

Quote:
Originally posted by 8kGoodENuff


Yeah... it starts perfect and the idle (550 RPM) is normal (meaning no spuddering or anything)... it's just that annoying shake that it has now. I didn't do a compression test but I did hook up a vacuum gauge and the reading was around 20" +/-0.2". I think if the timing was off, I think the needle would make some drastic changes, but then again I wouldn't know that... just assuming so. Oh... and also got great gas mileage on the way home as well from the shop... so idk... maybe I'm just overreacting.

I was doing some research outside of these forums and it seems that the shake at idle is a common thing with a boxer engine. Most actually seem to admit having it while only a select few say they don't.

Andre
Our 99 2.2L runs smooth as silk at idle, no shake. When we swapped out the stock heads with the DynaCamshaft reworked heads/valves/mild cam grind, we also took all the injectors and sent them to a shop in the northwest, and had them ultrasonically cleaned and flow tested. Anyways, all that extra TLC certainly paid off. The engine purrs like a kitten. http://www.witchhunter.com/

On With The Job
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