My 89 Vette recently started idling too fast. When I start it with the engine cold, it idles @ 1400 RPM's. As it warms-up, the RPM's gradually climb with the temperature to 1700 RPM's. Has anyone had this problem ?, or have any knowledge of it. I'd sure like to hear from you. Regards Mike, email- duceee@msn.com

 

Mike,

I have not seen this before, but two things I would look at first, are the Throttle Position Sensor (TPS) and check the timing. The TPS should be .54 volts at idle (I think it is measured between the top two conectors on the TPS - check you manual). I would check it with the key on and the engine off first and then start the engine and make sure it remains at .54 as the engine warms up. With the key on and the engine off the voltage should be .54 at idle and when you move the throttle toward wide open, it should gradually increase to around 4.5 volts. If it doesn't, then the TPS is bad. Also, check the timing to see if it is changing as the engine warms up. Hope this helps.

Mike

 

I have heard of things like this with other GM products, but not with a vette...with the other GM products it was a ECU issue..
also, does that engine run by means of a crank or cam sensor? i have seen some vehicles have some idle issues when the cam or crank sensors go south...

 

Mike, not you Mike, the other Mike, Good info on the tps. Did you get this from a shop manual or is this standard values on injected motors? And good luck on the fast idle problem Mike, no, the other Mike. Post your results so we all know what was the cause.

thanks

 

Hello All, I have not solved the 'Fast Idle' problem yet. For sure I will post it when I solve the problem. Regards, Mike [with the problem]

 

Hi CRVTTBASS, Thanks for the info in your email. I sent a reply, but the postmaster sent it back, so I'll thank you here. My "Check Engine" lite has never come on so I haven't checked for a code readout. that's my next move. Then I'll do as you suggested and spray Electronic spray cleaner on the wires inside the MAF. I'll let you and others know here on the forum how I make out. Regards, Mike with the 'fast idle' problem

 

Hello All, I have finally solved my Fast Idle problem. I replaced the Idle Air Control Valve [ IAC ] Niehoff Part Number 21773. $49.95 at Kragen Auto Supply. It took about 15 minutes to install it.