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How to: Clean a Zetec IAC

104K views 94 replies 37 participants last post by  amc49 
#1 ·
This thread is to help everyone with that nasty idle problem with higher mileage Zetecs.

Tools needed:
2 Jack stands
1 Jack]
flat head screw driver
8mm socket with ratchet
(1/4 inch is recommended, 1/2 inch is hard to use in tight spaces)
Carb/Choke Cleaner (semi large can depends on how much buildup there is)


Step 1: raise and support focus with jack stands


Step 2: get your flat head screw driver and take off the intake tube on the throttle body so you can gain access to the IAC when you take it off from underneath


Step 3: get under the car with your 8mm socket ratchet and start feeling up in behind the starter on the intake manifold there should be two bolts loosen them up and then take them out with your hand, they are easy to take out. The IAC Looks like this on the intake manifold, the silver cylinder looking thing.



here is a pic of the IAC location from under the car you can tell its really hidden away





Step 4: once the IAC bolts are out it should be sitting in there because of the tight space, it wont fall out because there is a wire connected to it. get back on topside of the car and grab this wire that my index finger is pointing/laying on and that is the wire you can use to pull the IAC out..

dont jerk manuver the IAC around from atop so that it can easily be pulled out.


Step 5: grab your carb cleaner and go to town on inside of the IAC valve




BEFORE






AFTER






Step 6: let the IAC valve dry in the sun or just air dry until no cleaner comes out of it. then reinstall!

Hope this helps everyone that has this problem! [thumb]
 
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#2 · (Edited)
Use THROTTLE BODY cleaner. Most cars have a teflon or similar coating inside metal intake parts. Carb and break clean will take it right off and it will start to pit like a son of a bitch. I found this out when I cleaned the IAC and throttle body in my Ranger. Had to buy a new throttle body and IAC. The butter fly in my throttle body seized up and the IAC seized also. Better safe then sorry.
 
#3 ·
Use THROTTLE BODY cleaner. Most cars have a teflon or similar coating inside metal intake parts. Carb and break clean will take it right off and it will start to pit like a son of a bitch. I found this out when I cleaned the IAC and throttle body in my Ranger. Had to buy a new throttle body and IAC. The buffer fly in my throttle body seized up and the IAC seized also. Better safe then sorry.
It can cause pitting, but most likely wont.. the carb cleaner is more harsh on the sensors around the TB because it is formulated to remove heavy varnishes found in carburetors. so that means it should be 100% okay to sue on the IAC since it is a valve. dozens of people have used carb cleaner on it it just is stronger than the Throttle body cleaner
 
#15 ·
(1/4 inch is recommended, 1/2 inch is hard to use in tight spaces)
Thanks for the great write-up!!

My 1/4-inch Craftsman ratchet was too large for the bottom IAC bolt. I used a mini combination wrench (8mm or 5/16-inch). You don't need alot of leverage - IAC bolts are only torqued hand-tight. I also found a telescoping mirror to be helpful.

Before starting, grab a handful of Q-tips -- you'll need them to help the cleaning fluid do its job.

This job is definitely do-able -- but requires PATIENCE!!
 
#16 ·
[8D]I prefer the easy way: idle the engine and squirt the cleaner in the throttle bypass until it stalls and let it sit for an hour. I know your way is better, but my way is easy enough to do every oil change or so.[8D]
 
#17 · (Edited)
got my IAC removed...went to look back at these pics to compare...there gone..

My iac was pretty clean...I got a replacement, just in case....the new one has a spring inside. Installed it and the motor REVed high..took a while for it to idle down....
once it calmed down it was nice and smooth..UNTIL I TOUCHED THE THROTTLE....it peaked again in gear!
Took it for a spin....it was like having the cruise control on...gonna take it off, and put the old on back and see if the new one was bad..

anyone else have this issue?..
 
#18 ·
Rob,
I'm sorry to say that I have had the same issue. Replaced the IAC with a new one but could not the gasket on. (major mistake). now when i start the car it revs way too high for like 5 minutes and then comes to a normal idle. But the thing is messed up because it accelerates on its own at 40 mph with my foot off the gas.

I will remove this IAC and put the gasket on like i should have. According to the experts/moderators on this site, a vacuum leak around the gasket can be the cause. Since all i fooled with was the IAC (plus cleaning TB) it appears the gasket (lack-of) is implicated.

I'll report back whhat happens with the new gasket.
 
#22 ·
Forget about the photos - they're not important.

On a ZX3 at least, the IAC is mounted in a God-awful, nearly invisible place (under the intake manifold) and is accessed mostly by sense-of-touch, so photos won't help you. If Ray Charles owned a Focus, he could do the job as well as any of us. [scream] (not sure if that's the best emoticon...)

Once the unit is removed, it's pretty obvious what needs cleaning, if that's the route you choose to go.
 
#24 ·
IAC pics

Okay, so I cave-in easily to peer pressure.

I was under my car today and decided to take a couple of pics for those who can't find their IAC valve.

These pics are of a 2002 ZX3/Zetec with factory IAC, taken from the vantage point of lying on your back under the front end, as if you are replacing the oil filter (ie., driver's side is on your left). In all pics, the IAC is identified in red.

Here is the simplest view of the IAC in relation to other junk:





If you scoot over towards the driver's side a foot or so, here's the vantage point:





Here's a zoomed-in view of the previous pic for those of you with astigmatism:





Here's a zoomed in, larger-than-life view of the IAC:





Good luck! And remember - without patience, IAC means "infuriating agonizing chore"!
 
#27 ·
Someone should nominate that last pic to a thread on the starter wire nut sizes. People here are always asking about what the nuts look like. A 13 mm. and a 10 mm. The 13 on the left in pic does not come loose, it stays with the starter.
 
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