Hello,

Have a 1984 Corvette, with 35K on it, have had the car for 29 years, always garaged and maintained.

About 200 miles ago, the car started to have a fast idle at a cold start up (1500 RPM's) - when the car was operating at normal temps (180* coolant). (900 RPM)

Then the idle would kinda come back to normal. (900 rpm)

Yesterday, I got an "Check Engine" light, so I pulled the ECM code, and it was 21, "Throttle Position Sensor" (TPS).

With the battery disconnected, I disconnected the 3 pin connector to the TBS- the (3) wires lead looked clean, as well as the 3 pin connector, I did clean these 3 pin connector - let it dry, then reconnected it back to the TPS, and still the Check Engine light went on, shortly after I started the car.

So I am wondering, what would happen if I disconnected the 3 pin connector that connects to the TPS? What impact would that have on running the car?

Also there's a metal pedal that is part of the TPS, with the car running, I pushed down on the metal pedal, and it did "not" change the idle speed. What the purpose of this TPS metal pedal?

In reading the FSM, it says that if the TPS is replaced that the TPS and both Intake Air Control's (IAC), have to be calibrated with a voltage meter- is this correct?

Again, the ECM error code is 21, (Throttle Position Sensor TPS) - could it be some other problem other than the TPS?

In advance, thanks and all comments are welcomed.

Mike

 

Yes, you need the tps. I'd be more worried about setting the correct tps voltage over the iac valves.
You can test the tps, all you need is a voltmeter, you'll need it to set the tps min voltage.

 

ex-x-fire,

Thanks for the prompt reply.

R U from WI?

I grew up in SE WIS, now reside in TX.

 

I'm from the very sw corner of lower Michigan, been living in the Sheboygan Wi. area for nearly 12yrs now. I like this area, we get less snow then back home.

 

Folks,

Thanks for your assistance, it was a bad TPS - so I installed a new one - and problem fixed.

Again, Many thanks to all.

 

Good job!

 

ex-x-fire,

1.) I need to replace the upper / lower radiator hoses, I am looking at the Goodyear pre-cut/molded and the Gates pre-cut/molded, and Gates cut your own.

Any comments or other suggestions?


2.) Need to replace the oil pan "gasket" - apparently the original one was cork. Should I replace the old oil pan gasket with Fel-cor "cork", or their Fel-Cor Pro Perm Plus.

Any comments or other suggestions

 

Both those vendors make good hoses, I like the direct fit hoses.
Pass on the cork gaskets, the 1 piece molded gasket is the way to go. Not a bad job to do on a c4 vette, esp early ones.

 

Double post deleted,.