Hey all,

I have a '85 Camaro/2.8 liter/v6/MPFI that's idling to fast. I've tried adjusting it but nothing seems to slow it down. Does anyone have any suggestions for me to try? Thanks in advance for any and all help.

 

What did you adjust when you "tried to adjust it"?


You're first thing to check for is vaccuum leaks. They'll ruin your idle, no matter what.

 

First of all thank you for replying, I appreciate the help. I backed the screw out on the throttle body lever. It didn't help much. Sometimes when I start the car it idles at a good slow speed and then speeds itself up and won't slow back down. I'm trying to find a diagram for the vaccuum lines now. A neighbor said the throttle position sensor could be bad so I put a new one on it, still fast idle. The idle is so fast the car jumps when I put it in gear.

 

I've learned, through having this problem myself, that there are tons of things on this car/engine that can contribute to a high idle.

For now I would try to set the throttle screw back as close to the original setting as possible. Because moving it means that you change the stock reading on the TPS. For example, if you lower the stop screw, the TPS is now going to constantly read that your idle is lower than the stock setting, and will try and compensate for that. It just throws it off.

Also, check your Idle Air Control. If your car isn't getting enough air while the throttle plate is closed, the IAC will open in incremints to allow more air into the engine. If it gets stuck open, too much air will constantly be flowing into the engine, which means a high idle. If you take it off and if it is dirty, you can clean it, or a new one can be had for $30-ish.

Until you get that vaccuum diagram (sorry I don't know where to point you to one) you can always just check all the ones you can see - there are plenty. If you've got some carb cleaner, spray that around some vaccuum lines, and if the idle changes for a moment, you've found a leak.

The Mass Air Flow sensor was one of my culprits. A can of some MAF cleaner really helped my idle.

 

Hey thanks again for the help! I will set that screw back like it was and check the Idle Air Control Valve. I did spray starter fluid around the hoses and MAF, it sped up when I sprayed around the maf, I took that off and cleaned it and fixed the hose leak. I found a whole bunch of vac. diagrams on this site, looking at them now to make sure they're all hooked up.

 

Sounds like progress. Keep us updated.

 

Hi,

had the same prob with my 88 Firebird (2.8). Get someone with a scanner or better yet a laptop with the winaldl software. Now you can read the tps-signal (throttle position sensor). Mine was 7.9 negative. Here is how it´s done the correct way.Worked well for me.

https://www.thirdgen.org/tpimod2

 

Hi,

had the same prob with my 88 Firebird (2.8). Get someone with a scanner or better yet a laptop with the winaldl software. Now you can read the tps-signal (throttle position sensor). Mine was 7.9 negative. Here is how it´s done the correct way.Worked well for me.

https://www.thirdgen.org/tpimod2

 

Hey thanks,
I will try this and see if it helps. I have a laptop, going to try and find the winaldl software.

 

Winaldl is freeware, you find it with helpfiles here http://winaldl.joby.se/

very easy to work with, works well with Win XP

you just need a cable which connects your OBD-Port ( under the dash) to the PC ( serial com port).

 

I downloaded winaldl, but my soldering skills suck so I'll need to buy a cable. I was shocked to see how expensive they are!

 

Check out this post you will find the diagram you need. It is up at the top of the page. "Original Performance w an 87 2.8 V6 wanted"

 

A leak on the intake somewhere can cause a real high idle. I have not had this problem yet on my camaro, but on my jeep (being a side mounted intake) two of the upper intake bolts where loosening slowly and leaking right there at the gasket, and the idle slowly went in a week period from 1k rpm to literally 2k before I pulled over, and literally was able to lift up on the intake and the idle dropped.

So, possibly check the gaskets around the intake by spraying something like a little around suspected areas wd40 and listento the idle. The idle should jump. I've heard of people using an unlit propane torch and doing the same thing as the wd40 method. One more method is using an ultrasonic probe. http://www.uesystems.com/

Good luck!

 

Hey thanks for the advice about the intake. I did find that a vac hose was completely off of the bottom of the intake where it was impossible to see that it was missing. It's idling considerably slower now but a new problem has started, it's 'smothering' and tries to die when I give it gas.