Question on high idle after mods
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Originally Posted by Nick Williams
Bill, with your foot off the gas what does the TPS read and what are the IAC counts at idle?
Bill
Have you checked to see if you have a vacuum leak? If not, take a can of starter fluid or carburator cleaner and start spraying all around the intake and tb. If you hear a change in idle you just found your leak.
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Originally Posted by Nick Williams
Bill, with your foot off the gas what does the TPS read and what are the IAC counts at idle?
If the IAC counts are at "0", then that is the problem. Have you drilled the hole in the blade bigger? If so what size? If you adjusted the set screw then you may need to back it off. Get those IAC counts up to 30 to 50 and you should be fine. You should do a TPS reset when finished so it reads 0% throttle with your foot off the pedal.
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Originally Posted by Nick Williams
If the IAC counts are at "0", then that is the problem. Have you drilled the hole in the blade bigger? If so what size? If you adjusted the set screw then you may need to back it off. Get those IAC counts up to 30 to 50 and you should be fine. You should do a TPS reset when finished so it reads 0% throttle with your foot off the pedal.
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Nick, let me also tell you this. Sometimes when you leave a light, go to shift to second and it will act as if it is going to fall back when you push in on the clutch to shift, then it just jumps up and stays there. Very weird.
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Originally Posted by Nick Williams
If the IAC counts are at 0 you most likely have a vacuum leak somewhere.
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Now another news flash. I was driving home tonight and turned the air conditioner on. The car ran perfect. No high idle, nothing, idled perfectly when driving, push in on the clutch, dropped right down to where it is supposed to be. Turn off the air conditioner and, bam, back to the same high idle. Does this turn on any light bulb for anybody as to the problem?
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Originally Posted by DramaFoYoMama
I wouldn't count on that working very long. That worked for me the first time I turned on the AC. After that, it was back to the same old crap. 
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I guess I shouldn't have used was in my reply. I thought about that before posting because it implies that I have fixed the problem. I apologize for that. I am going to start tuning as soon as I get my package. I will let you know whether it's just a tuning problem or if there's something physical I have to do. 
The TPS is adjustable. It's the same design that GM has been using for ages. The TPS voltage is supposed to be around .5 VDC. If you strap a DVOM to it and read the voltage. Loosten the screws and move the TP Sensor, the voltage will change. Try to find out what the TPS voltage should be at.
I don't think that that would cause such an ungodly high idle, tho. You mentioned that the MAP (-?) sensor in the back wasn't secure? That might do it. If you had a scan tool, I'd say take a look at what the O2 sensors are reading. If it's Lean, then of course you have a vaccuum leak. A leak severe enough, when installing a new manifold, would cause such a high idle. Spray some non flamable brakeclean around the mating surfaces of the manifold. If the idle changes, then you've found the leak.
It's an old trick, I'm almost positive that it's brake clean..... Look into the trottle cable thing too. If that's the case, then cheap and easy first. Right?
I don't think that that would cause such an ungodly high idle, tho. You mentioned that the MAP (-?) sensor in the back wasn't secure? That might do it. If you had a scan tool, I'd say take a look at what the O2 sensors are reading. If it's Lean, then of course you have a vaccuum leak. A leak severe enough, when installing a new manifold, would cause such a high idle. Spray some non flamable brakeclean around the mating surfaces of the manifold. If the idle changes, then you've found the leak.
It's an old trick, I'm almost positive that it's brake clean..... Look into the trottle cable thing too. If that's the case, then cheap and easy first. Right?
Last edited by bayer-z28; Aug 3, 2005 at 01:09 AM.
Originally Posted by SS125
Now another news flash. I was driving home tonight and turned the air conditioner on. The car ran perfect. No high idle, nothing, idled perfectly when driving, push in on the clutch, dropped right down to where it is supposed to be. Turn off the air conditioner and, bam, back to the same high idle. Does this turn on any light bulb for anybody as to the problem?
When you turn the AC on the computer recognises a load on the engine and it uses the IAC motor to bump the idle up a tad to compensate for the load. The load on the motor is what is lowering your idle. when you take that load away the idle returns to where it was. Idle Control, it keeps the idle where it should be.
The TP voltage is supposed to change with throttle plate angle differances. It tells the computer what the throttle plate itself is doing. The voltage does not change w/ idle, unless the computer changes the blade angle w/ the IAC motor.
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I don't think I have a vacum leak. I sprayed starter fluid all around the manifold and throttle body today, nothing. I now know it's not the TPS, I went to Murrays and he let me try one. No change. I'm taking the car over to PFE friday for tuning and see if they can fix it. I've had enough
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Took it to PFE and they fixed it. Those guys over there are great. I live in Rochester, so to go to Livernois in Dearborn or Hardcore in Flint was a haul. I was told about PFE by a client of mine and had never really heard of them. But, when I took it over there and talked to them they talked about things in the computer and engine that nobody at APE had ever mentioned or for that matter thought of before. (I've had this issue with the high idle ever since the heads and cam went in the car. APE never really figured it out.) And Shaun, the dyno guy definitley knows his ****. Greg and Gary also know these engines inside and out. I would recommend these guys in a heartbeat. They fixed the idle issue and some other problems that I was having. Great guys.