oem idle specs
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Nothing per se (ie, it's no different than anything built in the last 30 years) - Specs are 100 +/- Actual Rpms from Targeted in Park/Neutral; 50 +/- Actual Rpms from Targeted in Drive. Get a Scanner if you want to see what it's doing. Targeted Rpms vary with signal from the Coolant Temp Sensor.
Thread Starter
Racer
Joined: Sep 2005
Posts: 449
Likes: 1
From: Victoria
Nothing per se (ie, it's no different than anything built in the last 30 years) - Specs are 100 +/- Actual Rpms from Targeted in Park/Neutral; 50 +/- Actual Rpms from Targeted in Drive. Get a Scanner if you want to see what it's doing. Targeted Rpms vary with signal from the Coolant Temp Sensor.
I have also noticed at times while driving and removing foot from accelerator,slow to drop of rev's and sometimes maintains the higher rpms 800 or more?
Team Owner
Joined: Jul 2004
Posts: 28,464
Likes: 3,288
From: Hartford WI
The coolant Sensor comment has me interested,obviously the one under the TB? Could this also leed to varying idle ,eg even with engine warm and after driving say idles one time at 600rpm next time stopping 800rpm in "drive"?
I have also noticed at times while driving and removing foot from accelerator,slow to drop of rev's and sometimes maintains the higher rpms 800 or more?
I have also noticed at times while driving and removing foot from accelerator,slow to drop of rev's and sometimes maintains the higher rpms 800 or more?
If that is so, it could be a TPS issue or an idle issue. Hook up a scanner or get a TPS voltage. With the engine off and the key in run, you slowly depress the throttle. The voltage should climb up steadily. Any drop means you have a dead spot in the TPS. Also, have you cleaned the throttle body lately? I would remove the TB and the IAC and the IAC housing, get a new gasket and reinstall after cleaning all the passages. After that, reset the min idle and TPS. Of course your timing must be spot on.
Thread Starter
Racer
Joined: Sep 2005
Posts: 449
Likes: 1
From: Victoria
It would have to be varying in it's output to the ECM. Not sure if I have ever heard of that before where a temp sensor keeps varying the output
If that is so, it could be a TPS issue or an idle issue. Hook up a scanner or get a TPS voltage. With the engine off and the key in run, you slowly depress the throttle. The voltage should climb up steadily. Any drop means you have a dead spot in the TPS. Also, have you cleaned the throttle body lately? I would remove the TB and the IAC and the IAC housing, get a new gasket and reinstall after cleaning all the passages. After that, reset the min idle and TPS. Of course your timing must be spot on.
If that is so, it could be a TPS issue or an idle issue. Hook up a scanner or get a TPS voltage. With the engine off and the key in run, you slowly depress the throttle. The voltage should climb up steadily. Any drop means you have a dead spot in the TPS. Also, have you cleaned the throttle body lately? I would remove the TB and the IAC and the IAC housing, get a new gasket and reinstall after cleaning all the passages. After that, reset the min idle and TPS. Of course your timing must be spot on.
Team Owner
Joined: Jul 2004
Posts: 28,464
Likes: 3,288
From: Hartford WI
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
A couple of us have had a CTS circuit toggling around the low to mid 200's regardless of actual temp, but idle didn't track it. Hard cold start, fan on, and no fast idle were the symptoms. For each case, it was the ECM. This problem sounds more like a vacuum leak or maybe a funky a/c request or an IAC Motor which acts as a Dashpot when you get off the throttle. A scanner or Digital DVM isn't going to pickup a lousy TPS because it will average the voltage readout. Use an analog meter and if the needle jumps around as you open the throttle slowly, it probably needs a new one. Log IAC counts when you drive it and get off the throttle and compare to Actual RPMS.
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