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Old 05-22-2014, 03:09 PM   #501
Dr. octagon
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I cleaned the **** out my IACV 5 times.....it looks like its brand new and the flapper spins as though it has a bb chra.

Bought a used IACV from my buddy and it now this one looks exactly like described above as well.

I tried both and still got P0507 repeatedly

Got fed up and started looking around the engine bay and found that the vacuum source under the intake manifold where my bov runs to dry rotted clean off.

Replaced the hose and idel went from cold start 2000rpm to 500 rpm.

Initial symptoms was: (also i am on speed density, NO MAF)

1. Cold start car drove fine, when at operating temp the cel would come on (P0507)

2. Car would go into limp mode and bog at exactly 2k rpm ( i would either have to slip the clutch or rev above 2k rpm not to bog down)

3. Idle rpm was 1025 fluxuating to 1075

4. AFR's were all over the place (sometimes dumping fuel at idel, sometimes 15.0 to 17.0 at idle, but crusing AFR was 14.7-15.00)

Some will say that the heat in combination with the placement of the cruise control module will tighen the cruise control cable, and the solution being to loosen the cable.

I dont have cruise control or the module so that was out.

Others will say tighten the throttle body cable, i did that too and now infact it is too tight. I am going to adjust it this afternoon.
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Old 06-11-2014, 04:58 PM   #502
H_wells3000
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Just did this. I had to go one step further and remove the two bolts on the side aswell and manually turn the little roller inside to break it free of the gunk before I could clean everything.

Idle was at 2k and pulsing. Did this and back to a very very happy idle again
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Old 06-29-2014, 08:42 AM   #503
4CeesunsII
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Default Cleaning worked for me

So, after all these replies, a month ago I did buy a new gasket, took the top off the valve, did the gasoline soak with q-tip wipe, and problem solved?
Thanks for the advice guys.
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Old 07-23-2014, 06:28 PM   #504
spdracr
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Cleaned the IACV but failed to clean the flap and my car still idles at around 5-400 rpm after warm. Upon cleaning flap, cars runs like its suppose to. Make sure you guys follow every step to the 't'. I really think if you hadn't posted this, My baby would still be suffering. Thanks Man (Also, make sure you guys wait until your car is cool before working on this as it might spue out coolant!!)

Last edited by spdracr; 07-23-2014 at 07:20 PM.
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Old 07-25-2014, 11:06 AM   #505
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Default Cleaning And Reattaching The IACV (Idle Air Control Valve)

When doing mine I ended up pulling the motor off so I could free the stuck valve.
I made a mark on the bottom of the motor across to the valve plate so I could realign it properly.
Used a Dremel to cut a slot in the 5 point screw. Didn't have the tool.
Took notice of where the tab was on the magnet as I separated the parts.
My valve was stuck and required some effort to free it, and once it was free I noticed quite a bit of buildup on the surface.

Car runs really nice now,
I thought I had noticed an irritating very slight hesitation when up shifting during normal driving and that is gone.

Initially I cleaned the iavc and got the code again so I changed my neutral position switch thinking that May have been the problem. After getting the code again is when I decided to pull the motor apart just to make sure everything was working well and found that the valve was stuck

03 wrx 5spd

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Old 07-25-2014, 01:29 PM   #506
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^^^ this ^^^

That valve should spin freely without the motor attached. Lots of carb cleaner and Q-tips until it doesn't hang up at all.
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Old 11-07-2014, 03:04 PM   #507
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Quote:
Originally Posted by 4Ceesuns View Post
Greetings, this is my first WRX thread.
I have a 2004 rex with about 200k miles. It was bone stock until 8 months ago I bought a Cobb tuner, stage 1 programming. Things were great. Then a week ago I put on the Cobb intake and air box. Things were great. Then later in the week (Friday) in stop and go commuting traffic, the idle in neutral was suddenly about 1900 RPM. I was able to “kick it down” to 1400, but this persisted for half an hour in bumper to bumper traffic, when inched forward putting it in gear yes the engine speed would drop, then return to 2000 rpm. Then when traffic opened up and I got back up to 80 mph, out of curiosity I put in the clutch and instead of 2000 rpm it dropped to 300, and nearly died. I verified this several times that the new idle was about 400, a couple times it raised to 900, now back to 400 and nearly dying.
Could this be the Idle Air Control Valve needing cleaning? Great thread!
Any suggestions where to start trouble shooting?
Thanks,
Gene
My 04 did the same thing, but only in heavy traffic. Turns out it was the cruise control cable, I added a little slack and it was fine after that. I think the issue was as the car got very hot under the hood, the cruise control box would warp a little bit, and pull the cable, increasing RPM's.
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Old 01-21-2015, 10:38 PM   #508
Jackstand Johnny
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Hey guys I just wanted to say that in my experience with removing the illogically soft Phillips head screws I was able to use the vice grips trick for the top right screw but there's no way to grab enough meat on the bottom left screw even with needle nose vice grips BUT I was able to easily remove that screw with a fat flathead driver and my power drill. It broke free mwith ease. With hardware like this that can easily strip you're sometimes a lot better off using a sudden high amount of torquenlike a power drill or impact gun for larger nuts and bolts.

If you happen to strip the screws I know for a fact that grab-it damaged screw extractor bits work perfectly. Good luck.
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Old 02-09-2015, 02:26 AM   #509
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I don't have any idle problems once my car starts but I notice that every once in a while on a cold start my rpms will drop abnormally low and then go back up to normal. after that there is no more problem. I was wondering if this was an iacv problem or pcv problem or what, im not really sure.
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Old 02-09-2015, 08:12 AM   #510
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Quote:
Originally Posted by Kevinsmith312 View Post
I don't have any idle problems once my car starts but I notice that every once in a while on a cold start my rpms will drop abnormally low and then go back up to normal. after that there is no more problem. I was wondering if this was an iacv problem or pcv problem or what, im not really sure.
If the iacv is gummed up, it will only get worse the lower the temp.

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Old 02-09-2015, 01:07 PM   #511
91_Rugby_Subie
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Possibly dumb question:
When I start my car I let the cruise light turn off, then crank it... because if I dont then the car shakes throws a misfire code.... Im pretty sure this is fuel related....

But Ive noticed recently when I start it when warm, the rpms will be at just below 1k for a split then jump to about 1200 and then back down to normal.... is this IACV related?

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Old 02-10-2015, 10:15 PM   #512
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Where is the IAC valve (idle air control valve) on the 2006-2007 2.5i impreza. I can't find anywhere that says where, all the pictures are always for wrx's and stuff.
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Old 02-15-2015, 08:59 PM   #513
Rumblefish61
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Default Resetting ECU after IAC clena up.

Great write up! Couldn't ask for more detail, even with the picture link issues.
I have an '07 Impreza Outback Sport. 2.5 N/A engine.
Completely stock.
80,000 miles on motor.
I figure that most of this write up still applies but am wondering what is the purpose of resetting the ECU & how to do it.
I'm a new owner of a Subaru & still searching the many forums for answers.
My little car is great & well taken care of by the previous owner but just today, my idle started to stumble a little & a bit slower to bring up the RPMs.
(I happened to disconnect the battery for a fog light install & idle was fine just before that. Probably a coincidence with timeframe.)
I always figured that these motors have a heavy flywheel which affected the build up speed in RPM's but today I noticed it was a bit slower than usual.
Going to try the clean up & replace the gasket, along with better screws.
Probably time for new spark plugs as well.
Thanks all.
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Old 02-18-2015, 07:12 PM   #514
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Quote:
Originally Posted by 2gnt2wrx View Post
If the iacv is gummed up, it will only get worse the lower the temp.

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Where is the iacv on the 2006 2.5i impreza 5mt located? i can't seem to find it or any diagram for it? I even found a post that said I don't have one but im not sure.
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Old 02-18-2015, 07:31 PM   #515
2gnt2wrx
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Quote:
Originally Posted by Kevinsmith312 View Post
Where is the iacv on the 2006 2.5i impreza 5mt located? i can't seem to find it or any diagram for it? I even found a post that said I don't have one but im not sure.
I'm not 100% sure but I know the wrx/sti from that year are drive by wire and don't have one.


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Old 02-19-2015, 12:15 AM   #516
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Quote:
Originally Posted by 2gnt2wrx View Post
I'm not 100% sure but I know the wrx/sti from that year are drive by wire and don't have one.


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what exactly does that mean "drive by wire"?
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Old 02-19-2015, 12:59 AM   #517
2gnt2wrx
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It means that an electric motor is attached to the throttle body to control the angle of the throttle plate, rather than a cable that goes from the firewall to the throttle body.

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Old 03-11-2015, 06:10 PM   #518
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Hate to bump this, but whats the best way to remove the screw that's closest to the intake? Do you guys tend to remove the TB to get the IACV off?
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Old 03-12-2015, 01:10 PM   #519
tleith
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Great thread! Just cleaned the IACV and replaced the gasket, it was pretty gross inside. I followed the steps exactly and the car ran like the day i bought it. Took it for a drive, about 30 miles, turned it off and went to check my codes (CEL disconnected from the guy i bought it from) and now it runs like crap again. I pulled it back off and its not dirty. This has been the car from hell for the last 3 months. Is it worth re-cleaning even if i don't see any noticeable grime? I wont hijack this thread with the list of nonsense problems this car has, but the IACV cleaning seemed to work great--at first
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Old 03-12-2015, 07:47 PM   #520
2gnt2wrx
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Did you remove the motor from the iacv housing? Like I demonstrate in my writeup? Search "my iacv cleaning writeup" you probably still have gunk in the recess of the housing, you can't see it unless you follow my cleaning process.

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Old 03-30-2015, 07:13 PM   #521
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Another suggestion for the screws: use a wide flat blade screw driver and attach vice grips to the screw driver handle. The added leverage helps tremendously!
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Old 04-16-2015, 12:09 AM   #522
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Just wanted to add my .02 here. Op is 100% right on the new gasket being needed. Mine was stretched and worn out. Tried to be a cheap ass and ultra gray thee sumbish in. Let it cure for 12 hrs started fine and then as the idle came down it got hairy super quick as my intake manifold filled with coolant. I then tried to re use gasket and it sheared off a corner of gasket.
AZ and local flaps were all special order status, local suby dealer too had to order. Called Atlanta and over nighted it.

Installed it and the car looked like it had a blown hg for 20 min burning all the coolant out.

Long story short but the friggin gasket
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Old 06-06-2015, 07:58 PM   #523
Titter
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do you only clean the top piece you take off? or you do also clean inside the holes on the throttle body. thats not mentioned in the OP and the pics only shows the top piece nice and shiny

Last edited by Titter; 06-06-2015 at 08:50 PM.
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Old 06-07-2015, 11:59 AM   #524
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Quote:
Originally Posted by Titter View Post
do you only clean the top piece you take off? or you do also clean inside the holes on the throttle body. thats not mentioned in the OP and the pics only shows the top piece nice and shiny
I'd say if the tb is off the car, then yeah clean those ports. Else, not worth it unless they're really clogged. It's the rotating mechanism that needs to be cleaned n moving freely.


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Old 06-07-2015, 01:10 PM   #525
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gotcha, thanks!
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