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Discussion Starter #21
Might be too late. maybe that’s why I was getting some “smoke/sparking”when I hooked them up. 50/50 chance..... I will try tomorrow and see what I find out In case I didn’t wreck them. . I plan to buy one, but i like to know for sure the part is bad. REALLY appreciate the help.
Kevin
 

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Sorry, been out of pocket for a bit.

The IAC when right has pretty close to equal travel both ways, Set the idle screw on TB to get about 700-725 rpm warm engine with IAC unplugged and then plug it in to get 750-800 rpm if working right. That is how you neutral one to have range both ways. If you didn't change TB gasket you may be leaking there to bump idle speed up and common, many think you can reuse the gasket since they seem undamaged, but no. The silicone softens up and once removed then it leaks at the idle bypass passage where the gasket is so thin.

Short 8 mm. rachet wrench indispensible when changing IAC (from below) and I make a paper gasket for it to have the screw holes slightly smaller so it pinches the bolts to hold them in place, then you free up the third hand needed. There is a rubber gasket under IAC and I use the paper one right on top to add more crush to the rubber one which is expensive and not needed new. I've both removed and installed IAC in less than 5 minutes before if you get good at it.

The IAC can be cleaned but if it has the breather on it then it has vacuum assist and any solvent will ruin the diaphragm inside if you are not super careful, you do NOT dunk the whole thing in solvent. The shaft will not move until engine is running meaning hole has to be plugged. Hold the part with shaft vertical while carefully cleaning and don't let solvent drip up the shaft back to the solenoid, it has to cross that diaphragm first to get there.

Service DTC codes in the order they appear, the first one is what went bad at first and then the other things list as they go bad too. That can be mighty helpful knowing that.

If you ever show EGR codes on that year with the EGR DPFE that sits on two short little stub hoses under the air intake tube then remove those and buy 3 foot of vacuum line and cut in half to use it instead, you will have to remount the DPFE. I plastic wiretie it to the intake tube to also raise it up higher. The shorter mounting was known for ruining the sensors in months or even weeks, I went through 3 then the remount fixed the issue forever. The short tubes allow too much water in the exhaust to get into the unit too easy and it goes bad fast. Drape any excess hose down back of engine and you create a water trap to stop all water getting up into the sensor. Fixed.
 

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2004 Focus Wagon, Zetec DOHC, Auto
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^^^A good procedure if you don't have access to scan tools after the base screw has been "adjusted".

If you have access to the proper scan tool, then getting the base screw reset to the correct factory position would be more exact. A good video of this is here:

Also, there is a coating inside the throttle body and on the throttle plate that can be damaged by cleaning.

The service manual makes two things clear. The throttle body is NOT adjustable (via the screw), and it should NOT be cleaned. In real life, both of those things are done.
 

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Discussion Starter #24
Interesting that the throttle body shouldn’t be cleaned... I cleaned my throughly... I also sprayed my IAC with carb cleaner. And I know better how it can damage rubber parts. After testing the solinoids on both IAC’s (thanks for the procedure Paul) they attempt to move the pistons but I don’t know how far they move. Not getting a lot of distance. Both ohm test at 9.6. To me that means they both are not burned out. Sealing? I don’t know how I would test that. On my donor engine and car there is NO rubber gasket on either? I guess they disintegrate? Maybe my problem...
 

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Discussion Starter #25
Right now I’m soaking both pistons and holes solinoid up with kroil. From reviews on replacement IAC’s it’s about 50/50 them working, and new at Ford is $200+. Back to the junkyard maybe...
 

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I don’t know how far they move. Not getting a lot of distance. Both ohm test at 9.6.
Spec is 7-13 ohms so yours is OK in that regard.

I dont know how much absolute movement but as long as it is basically closed when unpowered and fully open (unrestricted airflow between ports) when powered with unrestricted movement in between it should be OK.

Paul
 

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Discussion Starter #27
I’ve been to the junkyard and got two more. I’m going to try cleaning them some with WD-40. So far all 4 have not had a gasket. It’s either I’m embedded into the plastic or it’s disintegrated. Can I make my own with gasket material? Going to check rockauto for a possible gasket...
 

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Discussion Starter #28
Rockauto has a figure 8 rubber gasket that would probably be a good seal. I’m think I’m going to try a paper one since all of the IAC’ s new show a paper gasket. Could it be brand specific?
 

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Yes, you can make a gasket out of flat gasket material. The rubber one 90% of the time is stuck to the intake, look up in there and you'll see it. Figure 8ish shaped thing. Leave it there and put the paper one on top of it, seals like crazy. Impress one to torque spec and pull it off to look at the crush marks, it doesn't get any better.

'..as long as it is basically closed when unpowered...'

Earlier design IACs yes but not these, they are sold new with the pintle about 1/16-1/8" open. Normal. The open provides like lightly opening the throttle at start before they have powered up. Engine starts easier.

The 'don't clean the TB' gag is because of a low stick coating which did not work for spit, and to scare you into buying new TBs, Ford and their crap. I've been cleaning them with that sticker on them since Tempos and not one issue yet. TRY to avoid getting any solvent into the TB shaft ball bearing, it destroys the super small oil seal that seals the shaft from vacuum leaks. And there is even a fix for that if you messed one up, BTDT.

One really good way to zero in on the exact TB butterfly setting by screw...............check the decel speed when you let off throttle on ATX, that slowdown is massively linked to the setting there, you can go from a good coast brake to virtually zero with a half turn on that screw. My wagon used to decel at 55 mph coast way too fast like the brake was dragging but not brakes. Moving that screw ever so slightly fixed that issue instantly.
 

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Rockauto has a figure 8 rubber gasket that would probably be a good seal. I’m think I’m going to try a paper one since all of the IAC’ s new show a paper gasket. Could it be brand specific?
The original gasket was molded rubber
307620

Same as Motorcraft CG756
Paul
 

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Discussion Starter #31
Appreciate all the input guys. I now have 4 IAC’s. Two that I sprayed carb cleaner in and two from the junk yard today. I’m using WD-40 as a solvent. I CANNOT get them to seal like I think it should. I determined this by spraying WD in the top hole. Now that I’ve read AMC49 I can understand a little opening. Which is what I have. Is there ever fuel vapor going through this IAC?
update: I made my first attempt to install the IAC. This is going to be fun laying under my car and blind... I couldn’t keep the gasket on so it’s “glued up” with a very thin layer of ultra black by permatex.
results to follow.
 

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Discussion Starter #33
I was asking because I was using WD-40 to clean them.. I’m fairly confident it won’t affect anything right😄. Almost got the IAC in! Tightening top bolt..
 

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Discussion Starter #34
IAC in. Truly a miracle.🙏🏻 I don’t think in all the years I’ve putzed around with cars that I’ve seen a worse engineered location. Suffice it to say we need lifts in our garages to work at home on cars, and forums for
Others to share their expertise.
I reset error code, and initial idle is about 1200 in park. I’ll lower it. I was just hoping I wouldn’t immediately throw a CEL. The last 2 came with about 30 miles on the odometer...28 to go..
Many thanks to all who have helped me with how- to’s along the way. On a 2002 ZX3 with a DOHC the ONLY way to remove the IAC is under the car... for those following this post. Final results to follow
 

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Discussion Starter #35
Well it didn’t take 29 miles..more like 3 miles...my OCB says I’m idling around 1400, so when things cool down I’ll try lowering it and see if the CEL goes away. I felt good about this junkyard IAC. Cleaned up nice, good movement... I now have till 11/1 to fix it, so if the idle doesn’t do it, I’ll let it go for a few weeks. Some work coming up, and to the in-laws for a week. I will post the final verdict...very important...... the whole purpose of forums IMO.
 
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