Bill, with your foot off the gas what does the TPS read and what are the IAC counts at idle?

 

Nick, I'll try to get that for you tomorrow and email you a file. I presume that I can get these out of autotap, correct?

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.

 

This is the way it was explained to me: click me

I am going to order the EFI package soon so I can get cracking on this problem.

 

Nick, I just put autotap on the car using "Throttle Position Sensor" and "Idle Air Control Motor Position Counts". The IAC Motor Position Counts never changed, It is always 0. At idle, the TPS reads .7 volts, I rev the motor and it would go to .8. I rev the motor to 4200 rpm and it goes to 1.1 volts, when I rev it and let of the gas, takes a bit of time to drop to idle at about 1100 rpm and the entire time the tps volts is .7. Isn't the tps volts supposed to change as the rpms go up and down? Could it be possible i have a bad TPS. If anybody wants me to email them the excel file with the autotap logging file to review I'd be more that glad to do this. The Woodward cruise is coming up and I really don't want to cruise Woodward at 2000 rpm.

 

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.

 

Nick, I just got back from vacation, so sorry I didn't respond right away. No, I have ont drilled the hole. It is exactly as it came from you I guess. When I first put this thing on the car, remember, I had a huge high idle problem, like 3000 to 3500. I had the set screw all the way out. I dremeled "elongated" the holes in the throttle cable bracket and it idles good when it is stopped. I did screw the set screw back in a bit to where it is touching the whatever it's supposed to touch to adjust it. Now like I said, it idles fine at a dead stop, but basically when your driving down the road and go to shift you might as well be power shifting cause the gas is still down and your shifting gears. I'll try to get a reading on the IAC counts, but all mine says is 0.

 

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.

 

If the IAC counts are at 0 you most likely have a vacuum leak somewhere.

 

Nick, if there was a vacum leak, wouldn't you have eratic idle all of the time, not just when you driving and have the cruise control affect. Or would it do what it is doing.

 

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?

 

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.

 

What have you done to fix this problem?

 

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?

 

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.

 

IAC's at 0= vacume leak! Try closing the hloe in the throttle body.

 

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

 

Figure it out yet?

 

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.