How to clean plunger IACV.

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Rizzo
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How to clean plunger IACV.

Post by Rizzo »

My 2003 cold started great,idled fine too.

After it would reach to operating temp it would drop RPM and stall out when I lifted off the gas between gears.

I have a 5 speed and it's a very cold spell in January. I live in MI.


Turns out the Idle Air Control Valve was my problem. The plunger had carbon on the tip and the Throttle Body had some inside too.

This would not allow it to close all the way creating an "Internal vacuum leak", Leaning out the Fuel Air mixture that the computer could not compensate for.

Here is a dirty plunger.

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Here is the dirty T/B intake port. Note all the grey material,looks like moon dust LOL. Also notice the two screw holes...

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SO let's clean yours.

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First disconnect the electrical connector at the base of the IACV. Then spray a penetrant where the blue arrows point, This is the open end of the two screw holes you've seen above.

Now aluminum and steel like to bond together over time.

Use a flat blade screwdriver and a hammer.

Put the screwdriver at the red arrows, Hold it firmly and then apply twisting force while you hit the handle with the hammer. This will send a shock down the screwdriver and then the screws and help break the bond.

Remove both screws and get the IACV off. Keep an eye on the small orange O-ring that you see in the dirty plunger photo.

Seafoam,WD-40,PB Blaster...almost anything will work for this. Spray a rag down and rub off the tip of the plunger and the base stem too.

Then spray the TB port and stick your finger in the rag and rub around the port. If you have a small plastic bristle brush you can use that too.

Next apply a very slight amount of anti-seize to the screws at their end. This will drag it over all the threads when you reinstall it.

Assemble is the reverse of removal. Tighten it snug,reattach the electrical connector. And you're good to go.
Last edited by Rizzo on Thu Feb 20, 2014 8:53 pm, edited 1 time in total.
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mikenmel08
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Re: 2003 Baja stalls when warmed up.

Post by mikenmel08 »

Very nice write up :cool:
Rizzo
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Re: 2003 Baja stalls when warmed up.

Post by Rizzo »

Thanks man.
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Hawk296
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Re: 2003 Baja stalls when warmed up.

Post by Hawk296 »

Excellent photos and nice writeup! I am glad you figured it out. And now I know what style IAC valves the naturally aspirated Bajas came with. Best of all, it didn't cost you anything!
Rizzo
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Re: 2003 Baja stalls when warmed up.

Post by Rizzo »

Hawk296 wrote: And now I know what style IAC valves the naturally aspirated Bajas came with. ....


This brings up a great point I forgot to mention...

This is the Naturally Aspirated or N/A Baja IACV.

The turbo models have a different design with a coolant journal run thru them. The point here is for efficiency boost my igniting warm air
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Hawk296
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Re: 2003 Baja stalls when warmed up.

Post by Hawk296 »

Since this is becoming the official Baja IAC thread, Just to clarify the above for future searches, The turbo Bajas do NOT have an IAC valve. They are "drive by wire" so the ECU opens and closes the throttle plate electronically to control idle.

There were two common types of IACs used on Naturally Aspirated SOHC 2.5s One is the kind in this thread. It looks to me that it was used on all Bajas. (If anyone does not have this type on an NA Baja, please say so) It is a plunger type that slides sideways into a bore which is mounted on the top of the throttle body and attaches from the drivers side.

It was also used on other models if you are looking to find one. 2000/2001 Auto trans legacy and outbacks, 2002-2004 legacy and outback (2.5 only) also used this IAC valve and SOHC 2.5 Imprezas use this valve as well.

The other type is a stepper motor with 3 ports. It is mounted on top of the throttle body with two screws with a rubber gasket in between. This is the one that has coolant running through it. It was used on 2000/2001 Legacy/Outback with manual trans. It was also used on some 2.5 foresters, newer Ej22s and all 2.0 liter turbo Impreza WRXs and all cable throttle 3.0 H6s. these will NOT fit a Baja according to the info that Rizzo has provided. Of course there are some oddball configurations even some mid year changes based on MAP or MAF, CA emissions or not etc etc.

So there are a lot of options out there if you need one, just check to make sure it is looks like the one in the pictures here before buying a new one.
Rizzo
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Re: 2003 Baja stalls when warmed up.

Post by Rizzo »

Thank you for clarification.
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LrgLnrd
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Re: 2003 Baja stalls when warmed up.

Post by LrgLnrd »

AWESOME!!!! Ive been trying to track down my warm idle/bog out issue and it seems like you just found it.
Definitely going to check this tomorrow...
I will let you know what I find
Greg
Rizzo
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Re: 2003 Baja stalls when warmed up.

Post by Rizzo »

SWEET!


And I also and equally feel bad you're having problems.
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darcuri
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Re: How to clean plunger IACV.

Post by darcuri »

Hello. I realize this thread is old, but I am looking for some help with my IACV and it is related to the information in this thread.
I have a 2003 Baja 5-speed with about 150k miles. Once the car warms up, the idle tends to oscillate between 750 RPMs and 1000 RPMs. I would like to see it stay steady at about 750, but it jumps up to 1000 or a little above for a few seconds and then drops back. I tried cleaning my IACV, but this did not resolve the problem. A while ago I purchased a new inexpensive one, and while it seemed to work for a while, it eventually started acting erratic again. I ended up putting the old (original) part back in the car.
i am wondering if anyone can suggest a good replacement part. I am surprised to see that their are replacement parts available for $20-25, but then there are many that sell for $250 or $300. How can there be such a broad range? The inexpensive part did not work well for me, but do i really need to spend $250+ for a good replacement part? Any experiences you can share will be appreciated. Thanks.
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kamesama980
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Re: How to clean plunger IACV.

Post by kamesama980 »

Inexpensive ones are chinese knockoffs may work for a few minutes.

Also make sure the throttle valve itself is correctly set up and there are no vacuum leaks. 17 year old cars tend to have lots of small vacuum leaks rather than a few big ones that are easy to find.
-Russell
"You don't get to judge me for how I fix what you break"
03 sport 5mt
05 turbo 5mt vf39 and other STI bits, 3" turbo-back
darcuri
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Re: How to clean plunger IACV.

Post by darcuri »

Thank you.
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