Cooling Fan
Thread Starter
8th Gear
Joined: Apr 2007
Posts: 8
Likes: 0
From: Brighton MI
Cooling Fan
Ok, my fan is coming on at stop lights after a couple of minutes. When the fan kicks on, the RPMs drop and the engine runs rough. Now I also have a problem that ive figured out with the valve by the fuel rail that controls the air into the cockpit, and the cruise control. Is there any way that all these problems are related? Thanks in advance.
Le Mans Master
Joined: Dec 2004
Posts: 5,488
Likes: 1,352
Ok, my fan is coming on at stop lights after a couple of minutes. When the fan kicks on, the RPMs drop and the engine runs rough. Now I also have a problem that ive figured out with the valve by the fuel rail that controls the air into the cockpit, and the cruise control. Is there any way that all these problems are related? Thanks in advance.
Le Mans Master
Joined: Sep 2006
Posts: 6,050
Likes: 147
From: Phoenix AZ
2021 C4 of the Year - Modified Finalist
idle drops
sounds like you have some issue with the oxygen sensor, or vacuum leaks and when the fan comes on, the Iac is already compensating for the O2 sensor/leaks and cannot react fast enough or adjust for the differences. In order to add RPM, the IAC adds air. To compensate for a defective O2 sensor, the IAC may already be wide open. or if vacuum leaks, closing into the carboned dirt in the throttle body, not being able to completely regulate as it should.
