Idles High On Startup Even When Hot
Thread Starter
Instructor
Joined: Mar 2010
Posts: 101
Likes: 0
From: Kissimmee Florida
Idles High On Startup Even When Hot
I have always noticed this problem. When i start the car it idles at 1300 rpm for 2 mins then drops to 650. it does this cold or hot. Any Ideas.
Another note: I was getting the code 33 and 36 errors. The codes were highly intermitt Been dealing with this for 6 months. Well yesterday it would not start for a few mins, just cracked and cranked. Well it did start and run bad then cleared up. Both relays were replaced and MAF sensor also. I think i finally got it fixed. I found that on the MAF PWR RELAY the wires on Pins A and B were burnt and were touching. It had some crap on it so i did not see it till i started looking hard. Had to rewire the 5 pin connector to the cable harness. So far so good.
Another note: I was getting the code 33 and 36 errors. The codes were highly intermitt Been dealing with this for 6 months. Well yesterday it would not start for a few mins, just cracked and cranked. Well it did start and run bad then cleared up. Both relays were replaced and MAF sensor also. I think i finally got it fixed. I found that on the MAF PWR RELAY the wires on Pins A and B were burnt and were touching. It had some crap on it so i did not see it till i started looking hard. Had to rewire the 5 pin connector to the cable harness. So far so good.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
When you start the car the ECM sets the idle to about 1200 RPM. It then lowers the idle gradually as the coolant warms up. If the coolant is hot at startup it will lower the RPM much more rapidly. It sounds like your ECM thinks the coolant is always cold. That will happen if the connection to the CTS (Coolant Temperature Sensor) is open -- might be a bad CTS, broken wire, corroded connector pins or the CTS connector isn't plugged in.
The CTS for the ECM is located on the front of the intake manifold under the throttle body.
The CTS for the ECM is located on the front of the intake manifold under the throttle body.
