Hey guys, I’ve been lurking on this site for some time now. Reading every thing there was and dreaming of camaro ownership; while waiting for a decent 3rd gen to pop on the market. Well there weren’t any in my “price range” that were solid so I drove to Ohio to pick my baby up.

Things have been great….until yesterday morning she idled very high @1800 rpm and the exhaust smelled like she was running a little rich

I know a few problems that could cause this just need your expert advice as the budgets tight this month
> idle air control
>temp sensor
>tps
>o2 sensor
Ps. The previous owner by passed the fan temp unit and installed a toggle on/off switch in the cockpit. Thx in advance -Matt

 

I'd start by removing the coolant temp sensor & ohm test it, get a thermometer & a pan of water, measure the resistance as it warms up (up to 240*), you can find the ohm values on the web, google GM coolant temp sensor resistence.

 

exhaust leaks can cause this to if it is before the o2 sensor.

As for the IAC, just remove the connector, if it gets worse, then it isn't that, if it stays the same, probably is that. Also could pull it off and clean it up, they always get dirty and clogged, so could be all it needs is a good cleaning.

As for the TPS, should have three wires. disconnect it and do a voltage test, and a resistance test. You can find many instructions on how to do that through the almighty google. OR as the car is running because it is a high idle pull the connector off. If it drops off immediately good chance that that is the problem.


As for the O2 sensor, uh.... well it will only vary from virtually 0 volts to 1. 0 being lean 1 being rich. Only way to test that working with a volt meter is you need to test it hot and cold, cold should be 0, 1 should be hot. I can't recall any other way to test it off the top of my head right now, quite tired.

For the temp sensor I believe the usual resistance is like 3.5k at 70 degrees F, but I could be wrong and it does depend on what car this is on.

 

thanks for the reply guys, just got a chance to dig into the car this morning and all the sensors are the factory originals dated 91. I think it be best if I just replaced both my iac and temp sensor. ill let ya know how it goes.

 

When I had a 1990 RS with a 305 TBI, i had a similar issue. What happened was that the throttle body wasnt bolted together tight, so it was leaking air. Because of this, the engine was working harder to get air in so it was running at a high RPM. It smelled like gas because of how it was running. hope that helps.

 

so I finally go a chance today to hit up auto zone only to find out it was closed early !!! thanks trans glam, I will keep that in mind when in in there. what parts were loose, if ya can remember. will update when there's a break in the case..... thank you everyone who has replied and not skipped over this thread

 

No problem. I dont quite remember exactly what was loose, but the throttle body was leaking air. It was easy for me to find though. hope that helps.