I am still working the bugs out of my TPI swap in my SS Monte Carlo. I am using the painless wiring harness with a new 1227165 computer and an ACXT 1099 prom. This is a mass air with coldstart injector setup. I am still getting a code 21 (TPS sensor). I have been tracing all the grounds and I am getting .12 volts through the black/white striped wire that grounds the TPS, MAT, CTS with the key on. With the key off, I am getting .02 volts. With the ECM unplugged, I am getting .18 volts.

Should I be seeing any voltage through this wire at all?

Any suggestions?

Also, the main computer fuse holder gets very hot to the touch with the car running. With the key on, engine not running it stays cool. Is this telling me I have a weak ground?

Thanks for any help anyone can give!

 

you may need to adjust the tps on your car just check the tech articles and should tell you the readings you need at idle and wot

 

UPDATE!!!!

I finally got it fixed!!! It was a simple, stupid mistake that cost me a new computer and a new TPS sensor that I didnot need.

The previous owner of my painless wiring harness cut off the mat sensor plug and the TPS plug. I took the TPS plug off my factory CCC wiring harness and wiried it exactly backwards. I had the ground on the bottom and the 5.0 volt reference on top. It should have been just the opposite.

The way I found this was I took the Chevy Thunder harness break down with all the voltages I should be seeing when the engine is on and compared it to what I was seeing. When I got to the TPS signal, I was seeing 4.56 volts instead of the .54 he recommends. Thats when I figured out that my ground and 5.0 volt wires were reversed!

The engine now idles like it should too.

Thanks to everyone who helped me through this agonizing process! I have just a few more things to button up before I put her on the road!

THANKS EVERYONE!!!