Idle problem
11-23-2001, 11:23 AM
#1
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Join Date: Oct 2001
Location: Madrid, Spain
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Idle problem
Guys,
It just happened to me, caught in heavy traffic, suddenly my ´84 3.2 carrera´s idle started "surging".
Instead of the reliable 800rpm idle, the idle went up at first to 1000rpm. Then up to 1100rpm, and after MORE heavy traffic, the idle started going up and down from 800rpm to 1100rpm.
Oil pressure gauge would go up and down with each 800-1100 "cycle", and oil temp raised to second white thin line (it´s cold today!).
Does anyone out there know what kind of problem am I facing? Is it serious?
It just happened to me, caught in heavy traffic, suddenly my ´84 3.2 carrera´s idle started "surging".
Instead of the reliable 800rpm idle, the idle went up at first to 1000rpm. Then up to 1100rpm, and after MORE heavy traffic, the idle started going up and down from 800rpm to 1100rpm.
Oil pressure gauge would go up and down with each 800-1100 "cycle", and oil temp raised to second white thin line (it´s cold today!).
Does anyone out there know what kind of problem am I facing? Is it serious?
11-25-2001, 03:41 PM
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Join Date: Oct 2001
Location: Marietta, Georgia
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2 potential areas to look at:
1. The 84 and later cars have an idle air control (IAC)motor that allows air to bypass the closed butterfly in the throttle so that the engine will actually idle. This is controlled by the computer under the drivers seat. This can go bad and cause the idle to surge as you are experiencing. The motor is located towards the rear of the car and is just behind the 90 degree rubber elbow betwee the air box and the throttle body. It is connected to the elbow and the intake manifold with hoses. On the left end of the IAC motor is a wire connector. Try unplugging that and see if it makes a difference. If so, you probably need a new IAC motor.
2. The car also has an oxygen sensor in the exhaust system. This also sends signals to the computer and is important in determining the fuel mixture that the engine sees. This could be the problem as well.
If neither of these are causing the problem, then a trip to your local Porsche dealer is obviously going to be on your agenda. Good Luck.
1. The 84 and later cars have an idle air control (IAC)motor that allows air to bypass the closed butterfly in the throttle so that the engine will actually idle. This is controlled by the computer under the drivers seat. This can go bad and cause the idle to surge as you are experiencing. The motor is located towards the rear of the car and is just behind the 90 degree rubber elbow betwee the air box and the throttle body. It is connected to the elbow and the intake manifold with hoses. On the left end of the IAC motor is a wire connector. Try unplugging that and see if it makes a difference. If so, you probably need a new IAC motor.
2. The car also has an oxygen sensor in the exhaust system. This also sends signals to the computer and is important in determining the fuel mixture that the engine sees. This could be the problem as well.
If neither of these are causing the problem, then a trip to your local Porsche dealer is obviously going to be on your agenda. Good Luck.