Hi All,
First time posting and long time 3rd Gen owner. Had 2 drive-able Camaros, a 1990 RS and this 1988 Iroc. Thank for taking the time to read over this.

A little background info as it may pertain to why the car does what it does. I had the aforementioned 90' RS for around 4 years. Ended up wrecking it and found a clean, no rust 88' body and transferred the engine, transmission, computer, wiring harnesses, etc over to it. The engine is a 350 w/ an Edelbrock Carb and headers and an aluminum 3 core radiator. Believe it was bored before we bought it. Runs absolutely great with the exception of getting a little warm but that is info for another thread. It has never been overheated. The car starts up just fine, idles just fine, and runs fantastically. Timing was set with a vacuum gauge. Yet when you go to turn off the car with the key, the engine continues to run for anywhere from 2 to 5 seconds longer. This happens almost every time with random exceptions of it shutting off immediately as the key is turned off maybe 1 out of 100 times. What is causing this?

If you guys need any additional info, please dont hesitate to ask and I will help any way I can.

Thanks again,
Rob

 

When it continues running, is it running smoothly at a normal idle, or does it get really rough and erratic? (dieseling)

 

Try shutting the engine off with the transmission in gear.

Do you actually know how far advanced the timing is set?

Over-advanced timing and run-on go hand in hand......

 

It seems to run fine after switching the key off but some times the last couple of strokes can be a little rough.

I havent tried turning it off with it in gear, i will try that and get back to you guys.

I want to recheck the timing to make sure it is where it should be and will report back. This is kinda what I was thinking could be the issue as well.

 

Hi DrBob. Is your coolant fan wired up direct? If so, the spinning fan acts as a power source supplying power that keeps the engine running for a brief time after the key is shut off. Just my guess as I've seen it happen before.

al

 

I think it is direct wired as I believe they come on when you turn the key. I will double check to be sure. Wouldnt have thought that could be an issue.

 

Then you need to install a relay in the fan circuit.

 

So in the process of installing a smog pump bypass pulley, new tension pulley, adding a radiator shroud, and installing my new dual fan setup I found something out. Since the new fans didnt have the same stock connection to the wiring harness I couldnt plug them in right away. I fired up the car just to keep the battery in a good light and low and behold when I went to turn it off it behaved normally. You are right, without the relay it was backfeeding and causing my issue. Im going to figure out a way to install a relay or have a manual switch to power off the fans right before the key is turned off. Thanks a bunch guys.

 

This is all you need and this is where you install the contact. Works like a charm for me and triggers the fans using the ECU just as if the heavy duty cooling fan was coming on or the AC was in use. Triggers both fans.

http://www.autozone.com/cooling-heat...=&model=&year=

 

"Timing was set with a vacuum gauge." You must utilize a timing light to properly set the timing. I'm of the mindset that your initial tiing is too far advanced. Without question, a car with the timing too far advanced is prone to the symptoms of which you discribed.

Good luck

 

I want to say thank you to everyone here. Putting a relay in place completely fixed the not turning off with the key issue. Turns off normally now. Thanks again!!!!