964 idle problem
 

89 C4, 60K miles. The engine idles perfect for 60-90 seconds at COLD startup. Thereafter and at all hot startups, the idle is very low and engine sounds of misfiring. This time peroid of 60-90 seconds is consistent. The engine does not stall, and power is good. The distributor drive belt is fine. I will perform the 60K tuneup after I correct the idle problem. If it is an engine temp sensor, where do I find it on the motor. I will be buying shop manuals - as soon as I can drive myself to the store!

if the 2 wire head temperature sensor has not yet been installed, now's a good time to do it. the old sensors had a single terminal in the white plug that's on a bracket with 2 other black plugs on the left side of the engine. it screws into the front of #3 head.

[This message has been edited by john walker's workshop (edited 08-04-2001).]

If it's like the 3.2 Carrera sensor, you have to take off the left rear wheel to get to it!.
Mine was easy to change, remember to use grease or some kind of lubricant on the rubber grommet otherwise it can be awkward.
Hope this helps and is not incorrect!
Rgds Ben

Hey John did Porsche do a Tech Bulletin on that temp sensor ???

There was a Porsche Tech Bulletin however put out in 1991 regarding the AIR FLOW METER wiring harness protective cover which somehow could come into contact with the "engine ventilation hoeses" and that= could in turn affect the air flow metering system and thus the idle, etc. The modification looks a little more involved than the temp sensor John is referring to. I too have idle problems but my 964 '90 C4 idle problem exhibits itself right from the get go at cold start and remains unstable, but never dies, even when warm (idle hunts). However, the exceleration is stunning but idle sucks.

BTW: Do you have a 1" diameter hole in your plastic 964 intake manifold like I do ? I'm curious what this hole is there for ? The location of the 1" hole is just to the left of the #4 intake runner, best to use a flash lite at night to see it. Should I plug that hole with a rubber grommet ? Could that hole be my idle problem source ??


[This message has been edited by 964Cab (edited 08-04-2001).]