IAC the problem?

Stang95fyvo · Sep 28, 2005

Hey guys...

So here is what i did...

I went to clean the MAF on my 1993 Thunderbird with a 5.0 and I unplugged the battery, then unplugged the MAF, then proceeded to clean it with q-tips and some electrical contact cleaner.

After reassembly, I started the car up and the idle started to fluctuate. Then the idle dipped to 500 rpms and then went lower, and then came up and repeated over and over until it went too low and died. Did I kill the IAC or the MAF by trying to clean it the way I did?

Just when I thought I had all the minor little issues with this car worked out, it goes and does this now. :damnit:

Thanks for the help. I need a quick fix because I might have a buyer for the car.

mo_dingo · Sep 28, 2005

did you possibly install you MAF housing backwards, or not fully seat the connector????
Scott

Blackened302 · Sep 28, 2005

i'd suggest removing the IAC and cleaning it, too.

Stang95fyvo · Sep 28, 2005

mo_dingo said:
did you possibly install you MAF housing backwards, or not fully seat the connector????
Scott

Nope, everything is as it should be. I checked the connections a few times.

I may try cleaning the IAC. Anyone else have a comment?

Stang95fyvo · Sep 29, 2005

Stang95fyvo said:
Nope, everything is as it should be. I checked the connections a few times.

I may try cleaning the IAC. Anyone else have a comment?

Also, I took it over to have the codes cleared and it threw the codes of EGR valve below minimum voltage and MAF sensor below minimum voltage. Did I possibly kill one of them or maybe both?

CManT1914 · Sep 29, 2005

When you unplug the battery for any extended period of time, it clears all the computers stored information. When you start up the car again the first time after, it's normal for it to act funny until it relearns everything. This can take several driving periods. But.......... it's possible you damaged the MAF sensor when cleaning it. If you don't have a Hayne's manual already, I'd suggest getting one. It has a section that talks about testing your sensors to see if they are still working properly. All you'll need is a digital multimeter. And FWIW, I don't see how cleaning the MAF could mess with your EGR though.

Stang95fyvo · Sep 29, 2005

CManT1914 said:
When you unplug the battery for any extended period of time, it clears all the computers stored information. When you start up the car again the first time after, it's normal for it to act funny until it relearns everything. This can take several driving periods. But.......... it's possible you damaged the MAF sensor when cleaning it. If you don't have a Hayne's manual already, I'd suggest getting one. It has a section that talks about testing your sensors to see if they are still working properly. All you'll need is a digital multimeter. And FWIW, I don't see how cleaning the MAF could mess with your EGR though.

Well, ever since I put on the flowmasters and removed the resonator, I have had trouble with the car throwing codes. Usually it is only when it is cold outside and it was always the EGR. If it takes several driving periods, does that mean it will cure itself? I really dont want to have to spend 50 bucks on an IAC if I dont have to. I unplugged the battery knowing it would clear all the info, but when I started it back up it threw a couple codes at me. I may try taking off the IAC and cleaning that freaking thing too. Is it possible that the car just isnt used to how cle3an the MAF is now and thus not getting enough air because the IAC has adjusted itself for a dirty MAF?

CManT1914 · Sep 29, 2005

http://www.muscularmustangs.com/iac.php

Check out this link. It walks you through cleaning your IAC, throttle body, resetting base idle, adjusting TPS, and cleaning maf. That should help you get this idle straightened out. Like I said earlier, it's worth getting that manual, if your IAC is bad, then all the cleaning in the world won't do any good.

Now about that EGR. What do you mean resonator? You said you put on flowmasters, and took off your resonator, do you mean you took off you cats? Just doing that should not effect the EGR. The EGR really has nothing to do with the exhaust downstream of the headers. It sounds like your EGR is a whole seperate problem. However......... EGR is disabled at idle and WOT, so it doesn't sound like that will be effecting you right now.

zenboy99 · Sep 29, 2005

You didn't bend the MAF sensor wire when you were cleaning it did you? My Dad is a master Ford Tech, he told me just to spray in electronics cleaner and not to use a q-tip. If you physically damage that wire it won't read the correct voltage.

Starman · Sep 29, 2005

do you still have the EGR hooked up?? If you do, pull it off and clean it with carb cleaner....or buy a new one (pricey)...it might be sticking and will cause your car to idle poorly/stall

Stang95fyvo · Sep 29, 2005

CManT1914 said:
http://www.muscularmustangs.com/iac.php

Check out this link. It walks you through cleaning your IAC, throttle body, resetting base idle, adjusting TPS, and cleaning maf. That should help you get this idle straightened out. Like I said earlier, it's worth getting that manual, if your IAC is bad, then all the cleaning in the world won't do any good.

Now about that EGR. What do you mean resonator? You said you put on flowmasters, and took off your resonator, do you mean you took off you cats? Just doing that should not effect the EGR. The EGR really has nothing to do with the exhaust downstream of the headers. It sounds like your EGR is a whole seperate problem. However......... EGR is disabled at idle and WOT, so it doesn't sound like that will be effecting you right now.

There is/was a resonator on the car right behing the 3-Cat stock Y-pipe. that just helped with the sound of the exhaust. I will probably just replace the IAC. I might be able to find a junkyard one that might still work.

Stang95fyvo · Sep 29, 2005

zenboy99 said:
You didn't bend the MAF sensor wire when you were cleaning it did you? My Dad is a master Ford Tech, he told me just to spray in electronics cleaner and not to use a q-tip. If you physically damage that wire it won't read the correct voltage.

I dont think I did. I was really gentle.

CManT1914 · Sep 29, 2005

Stang95fyvo said:
There is/was a resonator on the car right behing the 3-Cat stock Y-pipe. that just helped with the sound of the exhaust. I will probably just replace the IAC. I might be able to find a junkyard one that might still work.

I was thinking of an h-pipe.

EDIT: Another thing you can try. On the throttle body, there should be a stop screw that the throttle plate rests against, and another screw on the other side of the throttle body, that controls the IAC. You could try closing the IAC valve completely (tightening that screw) and raising the idle by the stop screw. If you have a more stable idle with the IAC closed, then it might be your IAC.

SeventyMach1 · Sep 29, 2005

Stang95fyvo said:
I dont think I did. I was really gentle.

Well [stongly suggested] pull the MAF back out & DOUBLE check that you did not bend or break the wires inside.

Also, you can test your IAC with a multimeter to see if the electrical side is okay.

Stang95fyvo · Sep 29, 2005

SeventyMach1 said:
Well [stongly suggested] pull the MAF back out & DOUBLE check that you did not bend or break the wires inside.

Also, you can test your IAC with a multimeter to see if the electrical side is okay.

Well I just got done cleaning the IAC and changing the battery (mine was over 9 years old, so that was why it was dying) and it all works fine now! Thanks guys. Thanks for the link too. That was very helpful. I might end up needing to reset the idle later on. It idles beautifully now. The IAC was complete black and nasty. It was really bad.

IAC the problem?

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Keep it lubed .... keep it straight .... and keep

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