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Discussion Starter #1
My original post was in the Supercharger forum: "89 A-trim 30lb injs... Well, I had a 75mm Pro-M Bullet with wiring problems, my stang started bucking, trying to cut off, and when I gave it some gas the RPM would do a quick dip before revving up, like it was choking. So I bought another 75mm Pro-M bullet, except this one is a supercharged calibration. I bought it used. Now that I got it on, the idle on my stang shoots up to 2k RPM immediately upon startup and stays there forever basically. The check engine light stays on, and occasionaly goes away, but will come back on as soon as you give it a little gas. I've messed with the idle control screw and got no response at all, and tried reading the IAC voltage, but couldn't get a reading (had ignition in on position). All while it's idling at 2k RPM theres a HEAVY aroma of fuel, so it's apparently running really rich. I don't know what to do next. The meter is correctly calibrated to 30lb injs, and I've made sure the meter is flowing air the correct way."

I set TPS voltage to .99 and made sure the Timing was correct. I've cleaned the mass air sensor, and still nothing. It still idles high. So now, I post here, thinking it's not the mass air meters fault because the idle is acting same as it was with the old meter. Maybe a vaccum leak? I can't find any though. Can anyone offer up any advice?
 

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did u try the idle set screw on your throttle body?
 

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Yes - could be a vac leak. What work was done to the car recently?

You say you had .99 on your TPS - I was going to say that your PCM could be dead, but usually you will not get a "normal" reading like .99 from your TPS if the PCM is fried, but I guess its possible.

Your car can/will run without the air meter hooked up - you will just get a check engine light and it will not run correctly, but it should not idle up for 2k, it the air meter is actually the problem.

Let me know what work you have done recently :)

Thanks
 

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did u ever run a k&n or any other oiled filter, if so i suggest removing the maf and cleaning the sample tubes sensor, with time the k&n oil will gun up the maf and cause problems
 

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check the butterfly in the throttle body. ??? The idle control valve might be stuck??? Swap it out.
 

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Discussion Starter #11
WAO Racing said:
check the butterfly in the throttle body. ??? The idle control valve might be stuck??? Swap it out.
I checked the butterfly, it was good... Had a little birt of dirt but I cleaned it out no problem.

I'm gonna buy a code scanner today and see what codes it's throwing. Could this high idle be caused by a bad 02 sensor maybe?
 

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bmo37 said:
did u ever run a k&n or any other oiled filter, if so i suggest removing the maf and cleaning the sample tubes sensor, with time the k&n oil will gun up the maf and cause problems
What can you use to clean it... im having the same problem as ShadowStang50 is having... mine hangs at 2k after tune/custom chip was done. If i use the brakes and let the clutch out so it brings the idle down it will stay down til i rev it up again. So im intrested in hearing some more suggestions. But i got a C&L meter which might be the problem.

SVT
 

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Did you guys have the wiring harness extensions put on? My 89 had a TSB on it so the dealer installed a small extension inline for the harness along the firewall behind the intake. I found these plugs to be the cause of my occasional high idle. It would idle about 2k and I could shut off the car and restart it and it would go away for a while. It was all because of loose connections in the terminals of these black and white connectors. Hope this helps.
 

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My idle decided to go up to close to 3000 rpm once in a while.

I cleaned the 10 pin connectors and it hasn't done it since.
 

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SVTCobraLTD said:
What can you use to clean it... im having the same problem as ShadowStang50 is having... mine hangs at 2k after tune/custom chip was done. If i use the brakes and let the clutch out so it brings the idle down it will stay down til i rev it up again. So im intrested in hearing some more suggestions. But i got a C&L meter which might be the problem.

SVT
goto any store and buy some electronics cleaner spray, and use a cotton swab to clean the wire, but be very careful not ot break the wire. :)

I agree with you saying it might be your c&l, pro-m's since they are calibrated electronically react better to tuning such as a custom chip.
 

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ShadowStang50 said:
Thanks to everyone so far for the help. I'll try cleaning the 10 pin connectors, as far as I know there is no wiring extension. Any other advice is much appreciated!
I would go to your local dealer and ask for one. IIRC it was a recall. The extension helps because the factory harness was barely long enough so when the engine twists it slightly pulls on the 10 pin harness causing the connections to get loosened over time. Clean up the contacts and make sure their all tight. You can check this by getting a ford male side bullet connector at your parts store and push it into each female side pin to see if it has been stretched out from being tugged at over the years. Hope this helps.

Make that two extensions. :D
 

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Discussion Starter #18 (Edited)
gtfour43 said:
I would go to your local dealer and ask for one. IIRC it was a recall. The extension helps because the factory harness was barely long enough so when the engine twists it slightly pulls on the 10 pin harness causing the connections to get loosened over time. Clean up the contacts and make sure their all tight. You can check this by getting a ford male side bullet connector at your parts store and push it into each female side pin to see if it has been stretched out from being tugged at over the years. Hope this helps.

Make that two extensions. :D
This is for 87-93 Mustangs?

Also, I got the idle problem fixed, it's back to normal. I took off the IAB, looked inside it, made sure the solenoid worked, put it back on, and it idles like normal now. While driving though, it still studders under very little throttle (crusing) like it did with the old mass air meter. I'm gonna pull all my plugs tommorow and see if maybe one is messed up. Under WOT in 2nd gear it studder a couple times, but every other gear was fine for the most part. Seems a tad down on power.

I ran a code scanner on it, it threw a MAF code out, something about the voltage. Code 66 I believe it was.
 
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