Renix idle problems - Long -

The problem I have is nothing new. When I start it up it revs to 3k rpms and then after a couple of seconds it drops down. But its very inconsistant. Sometimes it will go up to 2500 or 2000 rpms. What have I done. I replaced the tps and the IAC cleaned the throttle body real good even in the IAC spot. The Tps was calibrated but I only read 4.8v instead of 5v on A-B, smooth movement on B-C when I move the throttle. Mosty of the parts in the engine bay or new. Cps is fairly new. The only thing I didn't mess with is the FPR and the MAP sensor. If I unplug the MAP the car dies. I pulled the Vac line off the FPR but smell no strong gas or see any. This problem Im having is wierd cuz in the warm weather I can unplug the IAC and the car doesn't do this. But in the winter and the IAC unplugged the car idles very low to the point I need to gas it for several minutes till it will hold a good idle. There are 2 temp sensors I know of. One on the intake and another on the back of the head. The one on the head I know is used for the gauge. The other I remember replacing last year or so. But unplugging doesn't change the way the car runs. I need some help.



Thanks

BuGG

Bugg, I would first check for any possible vacuum leaks. Look around the brake booster and the vacuum fittings. If they look OK, then I'd suspect a bad IAC. It's normal to have a very slow idle with the IAC unplugged; this allows the IAC to "catch up" and restore a normal idle. It sounds to me like the IAC is sticking open upon start-up.

You might try removing it and spraying it with WD-40, and see if that changes anything.....

What model year is this on? In '87 and probably '88 there was the troublesome C101 connector. It is located on the firewall and most of the engine sensors are wired through it. On my '87, I was finally successfull in curing the problem you describe when I removed and cleaned each of the contacts in that connector. It's a real pain because they used a "grease" in the connector which now resembles something more like pitch.

idle issues

It is an 87 and I know the connector your talking about. You need a socket to get it apart right? How do you suggest I clean it. Remove all the gunk and clean each connector on both sides. Should I put dielectric grease on after Im finished?

Also, I just got a new IAC last week and the problem exsist still.



BuGG

It was a real bear to clean on my '87. I first tried a variety of solvents on each half of the connector and it seemed to give some temporary improvement. Last go around, I removed each and every contact from the connector body and cleaned them with solvent and a brush. I had to get a tool made by Lisle to remove the contacts. I intend to put some dielectric grease on it but I've not yet done so.

I had a problem like this on my 89, I ran a separate ground for the TPS (direct to the chassis) and it hasn't done it once since then.

I did not cut the ground, but rather looped this one in. did it as a temporary fix. I believe the actual problem lies with the computer not recognizing that the throttle is closed. sometimes bumping the throttle would make it stop, but it was the point where I was sitting in traffic idling at about 3500rpm. something needed to be done, and this temporary fix has been keeping all my problems under control for the past year or so. It also improved shifting and throttle response!