Idle and fan disaster!
01-07-2014, 10:00 PM
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Idle and fan disaster! I have a 96 z28 that will idle fine when cold. After warming up, the car will vary from 600 to 2000 in idle RPM (dangerous at a stop light). I have replaced the IAC valve, the throttle position sensor, the MAP sensor and the fan coolant temp sensor. The car doesn't seem to do this if put in neutral while the car is rolling. At a stop, in gear or in neutral it starts. Checked for vacuum leaks, and can't find any. Any suggestions would be greatly appreciated.
Also, the fans on my car do not come on unless the air conditioning is turned on. I unplugged the coolant temp sensor and they come on full blast. I assume that the ECM is OK since the fans come on when the sensor is unplugged. This is an annoying problem that I have been living with for some time now.
The car is stock with the exception of a K&M cold air and no codes are showing. I appreciate any suggestions from anyone who might have experienced these two issues.
Hello? Is there anybody out there?
Also, the fans on my car do not come on unless the air conditioning is turned on. I unplugged the coolant temp sensor and they come on full blast. I assume that the ECM is OK since the fans come on when the sensor is unplugged. This is an annoying problem that I have been living with for some time now.
The car is stock with the exception of a K&M cold air and no codes are showing. I appreciate any suggestions from anyone who might have experienced these two issues.
Hello? Is there anybody out there?
Last edited by jmtholt; 01-21-2014 at 03:11 PM.
01-26-2014, 08:44 PM
#2
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I have a 96 z28 that will idle fine when cold. After warming up, the car will vary from 600 to 2000 in idle RPM (dangerous at a stop light). I have replaced the IAC valve, the throttle position sensor, the MAP sensor and the fan coolant temp sensor. The car doesn't seem to do this if put in neutral while the car is rolling. At a stop, in gear or in neutral it starts. Checked for vacuum leaks, and can't find any. Any suggestions would be greatly appreciated.
Also, the fans on my car do not come on unless the air conditioning is turned on. I unplugged the coolant temp sensor and they come on full blast. I assume that the ECM is OK since the fans come on when the sensor is unplugged. This is an annoying problem that I have been living with for some time now.
The car is stock with the exception of a K&M cold air and no codes are showing. I appreciate any suggestions from anyone who might have experienced these two issues.
Hello? Is there anybody out there?
Also, the fans on my car do not come on unless the air conditioning is turned on. I unplugged the coolant temp sensor and they come on full blast. I assume that the ECM is OK since the fans come on when the sensor is unplugged. This is an annoying problem that I have been living with for some time now.
The car is stock with the exception of a K&M cold air and no codes are showing. I appreciate any suggestions from anyone who might have experienced these two issues.
Hello? Is there anybody out there?
No exhaust leaks? MAF good and working? Only happens in closed loop?
01-26-2014, 11:34 PM
#3
LT1's have 2 temp sensors. The one in the head is for the temp gauge on the dash and the one in the water pump is the one that the PCM uses to turn the fans on. When you pulled the plug and the fans came on is because the PCM lost the signal and I bet it gave you a check engine light. Anytime you have a check engine light, the fans come on automatically. Anytime you turn the AC on, the fans are also suppose to come on.
02-10-2014, 07:45 PM
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The fans don't come on unless I turn on the AC. When I unplugged the sensor on the water pump, they came on full blast. I bought a replacement sensor from Auto Zone and am being told that I should try a new replacement sensor from Chevrolet.
As for the idle issue, I cleaned the MAF and still have the erratic idle when the car is warm. It seems to only occur when I am stopped or slowly moving. Could it be that maybe I need to re-program my ECM? If so, how is this done?
As for the idle issue, I cleaned the MAF and still have the erratic idle when the car is warm. It seems to only occur when I am stopped or slowly moving. Could it be that maybe I need to re-program my ECM? If so, how is this done?