IAC..timing idk...

[A_+]

I've been doing some searching and Googling and I haven't found a solution to my problem(s) which seem to be common in this model. To begin, I have a 95 with a 302. Built heads , Gt40 intake , 70mm TB, 73mm MAF (I might have those numbers mixed up), #24 injectors and its running a custom tune (I guess) sct chip.
The car will hold an idle at about 1.5 2k so I figured it was the iac valve. I was going to replace it when I started hearing a slight knocking sound. I read around and people were saying it was probably bad gas and the sound was due to detonation or what have you. Well, the timing was bumped up a bit and the ping/ knocking noise went away for a while but now comes back after I pass 60mph and the rpm now stays at 2-2.5k till it comes back down. I know that the new higher idle us due to timing but has anybody else solved these issues?

 

[CC'S95GT]

My hanging idle was due to a dead spot in the TPS.

 

[rz5.0]

You should set your timing back at 10°

 

[A_+]

My hanging idle was due to a dead spot in the TPS.

I can check again but it was working well last time.....

You should set your timing back at 10°

Wouldn't hurt to try....

 

[rz5.0]

Well all the timing advance should have been done on the tune (chip). So if you add anything more than 10° at the distributor you could be way over advance.

 

[A_+]

I just might pull this damn chip and throw it away.....maybe get a handheld or something.

 

[rz5.0]

Hand held will not work on your 95. Get a retune.

 

[rz5.0]

With your idle that high i bet you have vac leak or some one messed with the TB stop screw..

 

[A_+]

With your idle that high i bet you have vac leak or some one messed with the TB stop screw..

No vac leaks. Triple checked for that but I guess a quadruple check wouldn't hurt. Tb top screw was tampered with buy another mechanic. He knew what he was doing though so I don't think he screwed anything up. I was contemplating a retune. I just don't want to spend that kind of money on something that might not work. I'm not even familiar with the whole "tune" process.....

Hand held will not work on your 95. Get a retune.

Son of a....!

 

[rz5.0]

Have you tried the whole rest base idle thing..

 

[A_+]

No. How's that go again.....?
Edit...I found a little write up....

 

[rz5.0]

Try it.

 

[ScottyDsntKnow]

Had this same problem on my 95 when I did the HCI. Dyno tune solved it. Fact is you have "built" heads which may or may not be a good port job unless you know the guy who did them and put them on yourself and an unknown tune. Is the MAF on there "calibrated" or is the computer tuned for it correctly? First order of business is to take it to someone who knows what they are doing as far as tuning a 94/95 computer (any shop that tells you they can't tune a 94/95 car is incompetent and should get 0 business from you btw) and see where you are at and properly tune your car.

 

[Addermk2]

high idle or hanging idle is usually due to a poor TB blade to bore fitment, or a vac leak. If you would like a retune, I offer a tune diagnostic and reflash service. The diag is free, the reflash isn't.

PM me for more details and in depth assistance fixing your issue.

 

[rz5.0]

/\/\ this guy can help you..

 

[A_+]

I pulled the chip today. It usually runs well after a small tweak so this time wasn't any different. It runs well but we'll see how well it runs on my way back home from work.

 

[rz5.0]

Crappy tune..

 

[A_+]

Crappy tune..

You call the chip people, tell them what you're running and they burn you a chip to install. Isn't that how it works?

 

[rz5.0]

Depends. Or you have a costume tune.

 

[A_+]

Depends. Or you have a costume tune.

I called sct and they had the last owners info on file and they said they burnt a chip for the parts that were on the car. All were accounted for. We'll see how it runs now. I might need to look at the tb blade again like was mentioned earlier.