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Discussion Starter #1
I had the moaning fog horn sound start on Sat. I did some searching and everything pointed to the IAC. The old one was pretty nasty looking so I decided to replace it instead of trying to clean it.

The new one did not fix it as it was still moaning like a biatch. I did another search and read that if the EGR ports had too much carbon build up it could cause the problem. I cleaned the EGR port on the upper plenum, the EGR tube and EGR itself and still no change.

I then got to playing with the hoses for the IAC and if I pinch the one from the intake tube to the plastic 90* elbow it would stop moaning. I tried new hose and it made it worse so as of right now I have a small c clamp pinching the hose almost completely off.

The only thing I did prior was I replaced the plugs and fuel filter Fri night as it was pinging pretty bad. The plug change (NGK TR55) and filter fixed the pinging problem and the IAC started the very next day.
 

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so you're pinching off the hose that supplies air to the iac valve?
Yes. If I don't pinch it down it idles at 1500 rpm ans moans horribly. With it pinched it idles at 1000 RPM and the moaning stops. The car runs fine with it pinched and I get no code.

I don't have it completely pinched off. If I pinch it completely off it dies. I thought it was the hose as it is swollen up so I put a new piece of hose on the sane size as what was on it (3/4" i.d.) and it made it worse. I couldn't hardly stand the noise it was so bad.
 

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Yes. If I don't pinch it down it idles at 1500 rpm ans moans horribly. With it pinched it idles at 1000 RPM and the moaning stops. The car runs fine with it pinched and I get no code.

I don't have it completely pinched off. If I pinch it completely off it dies. I thought it was the hose as it is swollen up so I put a new piece of hose on the sane size as what was on it (3/4" i.d.) and it made it worse. I couldn't hardly stand the noise it was so bad.
I bought a brand new IAC valve for my 'Bird, and it moans just like you describe. Did you ever figure yours out? I wound up putting the old one back.
 

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reset the pcm
I did that ... twice. How? I disconnected the battery and shorted the terminals together the first time. The second time I was changing my proportioning valve so I just had the battery disconnected for awhile. The noise came back...

That's when I gave up and put the old IAC back in.....

Not to change subjects, but I got a couples other gremlins I've been chasing. My engine runs really lean. The plugs are almost pure white. I thought big vacuum leaks, but I've fixed them all and have been running it awhile with new plugs. Recently I did the PI intake install and for giggles I took out the plugs and checked them out. They are very light tan to white ... again.

Why does this thing run so lean?
 

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UPDATE: Ok, I brought my new IAC back and exchanged it for another brand new one. After installation the car started, idled around 700 perfect and I let it idle for a long time with and without the AC on. It idled so nice, I revved it a little, then took it for a spin to the local store about a mile away.

Well, on the way home while I slowed down for the speed bumps in my subdivision, the noise returned. Not as bad, but I could definately hear it. When I slip the car into neutral, the noise goes away, and when I got home I idled it in gear and couldn't get the noise to return.

*sigh* Well, tomorrow I'm gonna get the evaporative control solenoid that it needs and we will see how it acts on a long trip (~200 miles).

The MAF is new (well a little less than a year old) and the ECM has been reset a couple of times. The PI intake didn't make a world of difference, but it does seem to pull better over 4500 (it actually seems smoother, but less punch at lower RPMs). I definately need to swap the Mark VIII torque converter in and get a tune to remove that RPM limit. I'll keep y'all posted.

As for the lean condition, GM, you may be right on with the lack of fuel condition. The fuel filter was totally plugged and who knows how long it's been like that. I'll read for plugs after a few months and see if anything has changed.
 

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I disconnected the battery and shorted the terminals together the first time.
That can blow all the electronic modules. There's a huge transient from the capacitors inside the boxen thru the circuitry; worse than a load dump.

You probably have a large air leak, if it will idle with that pinched off.
 

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Interested for sure. Slipping in here to semi-hijack, if I may.

Mine did this last winter....honking like a horn and racing up to high idle for a few secs....back down to nearly die......honk and race up again for a few secs....etc.

It was unpredictable, and almost dangerous. The car would pick some pretty bad times to kick the idle up to 2k. Doing it while stopped at intersections proved to be the least amusing. After the winter passed, the honking went away, but now the car wouldn't stay running unless holding the throttle; "two-footed-driving" was now used to keep the car running at stop signs and red lights.

Since then I've changed: IAC (twice), MAF, TPS, spark plugs/wires, cleaned the crap out of everything, etc.
I've reset the the PCM after every change by pulling appropriate fuse, and making only one change at a time.
I found one vacuum leak in a hose near the back of the intake.
Replaced that hose: no change. Then I've wasted an entire 2 lb tank of propane after that waving it around the engine compartment searching for any other vacuum leaks. Nothing.

Master486 and Guitar Maestro will probably want to chase me around and whip me with broken off car anntenas for this, but I finally had enough of the two footed BS and blindly throwing $$ at the motor in hopes of finding the cure so I bent the throttle tab just a bit to hold the idle up enough to stay running, alternator charging, etc. despite a bit of mine and others' lot better judgement. I didn't touch the set screw, and it's nothing that can't be simply and easily undone though, so.... Otherwise it tried to idle at 300 rpm, if it could. I've had zero problems since, but it's only been a few days so far. Colder weather coming with the seasons change will get the proof of the pudding, I bet.

Sorry for the hijack, but if you can expect what might happen next with yours by hearing my version of the story, you might be safer and perhaps closer to a better solution.
 

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Interested for sure. Slipping in here to semi-hijack, if I may.

Mine did this last winter....honking like a horn and racing up to high idle for a few secs....back down to nearly die......honk and race up again for a few secs....etc.

It was unpredictable, and almost dangerous. The car would pick some pretty bad times to kick the idle up to 2k. Doing it while stopped at intersections proved to be the least amusing. After the winter passed, the honking went away, but now the car wouldn't stay running unless holding the throttle; "two-footed-driving" was now used to keep the car running at stop signs and red lights.

Since then I've changed: IAC (twice), MAF, TPS, spark plugs/wires, cleaned the crap out of everything, etc.
I've reset the the PCM after every change by pulling appropriate fuse, and making only one change at a time.
I found one vacuum leak in a hose near the back of the intake.
Replaced that hose: no change. Then I've wasted an entire 2 lb tank of propane after that waving it around the engine compartment searching for any other vacuum leaks. Nothing.

Master486 and Guitar Maestro will probably want to chase me around and whip me with broken off car anntenas for this, but I finally had enough of the two footed BS and blindly throwing $$ at the motor in hopes of finding the cure so I bent the throttle tab just a bit to hold the idle up enough to stay running, alternator charging, etc. despite a bit of mine and others' lot better judgement. I didn't touch the set screw, and it's nothing that can't be simply and easily undone though, so.... Otherwise it tried to idle at 300 rpm, if it could. I've had zero problems since, but it's only been a few days so far. Colder weather coming with the seasons change will get the proof of the pudding, I bet.

Sorry for the hijack, but if you can expect what might happen next with yours by hearing my version of the story, you might be safer and perhaps closer to a better solution.
:rofl: Dude, that's EXACTLY the only fix that seemed to work well for me. I bent that tab too just so it would idle fairly decent! Since then I bought 2 new IAC valves, and tried setting the tab back where it goes and all the freaking problems returned. I've already asked in another thread for ANY AND ALL HELP and what everyone would do to track down my issues....
 

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I've already asked in another thread for ANY AND ALL HELP and what everyone would do to track down my issues....
Everyone who I consider the "go-to" people for these kind of answers has told me it must be a vacuum leak somewhere, and IIRC Guitar Maestro said it's hard to tell much more about it beyond that unless some kind of logging is done to check fuel trims and such.

Please note that I'm not endorsing my temporary fix as a solution to the problem until a tech here says it's ok to do that. But until then I'll keep looking for it....maybe I'll get whatever it is when I swap intakes.
 

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Discussion Starter #14
Here is what I enede up doing.

The hose from the intake tube to the plastic 90 deg elbow is 3/4" i.d. I found a piece of 3/8" i.d. hose with a 3/4" o.d. and used it to reduce the air flow.

The sound is gone and it idles fine.
 

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bending what tab?? you know there is a throttle stop screw that you can use to open or close the throttle plate right?
Yeh, the one Ford removes the head from. It was a lot easier just to bend that little tab with a pair of pliers... :zdunno:
 

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Yeh, the one Ford removes the head from. It was a lot easier just to bend that little tab with a pair of pliers... :zdunno:
you mean the one that can easily be replaced with a M4 x 0.7 hex head bolt :)
 

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So is this acceptable? I could've sworn I read somewhere here that manually adjusting the throttlestop was bad news.... :confused:

But, no apparant vacuum leaks, no codes, new MAF, TPS, IAC.....you know now that I think of it, what's the proper way to check the IACs function, and to check the pigtail going to it?
I wonder if the thing isn't getting the signal in the first place. Hmmm....
 

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So is this acceptable? I could've sworn I read somewhere here that manually adjusting the throttlestop was bad news.... :confused:

But, no apparant vacuum leaks, no codes, new MAF, TPS, IAC.....you know now that I think of it, what's the proper way to check the IACs function, and to check the pigtail going to it?
I wonder if the thing isn't getting the signal in the first place. Hmmm....
that depends on who you ask.....ask me.....of course not....but I have means and resources that the average enthusiast doesnt.....there are thresholds that the pcm is capable of living with....its beyond that when people try to compensate for huge issues that it can become a problem
 
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