I got a 1982 928. The car hadn't been truned on for about a year. I had to replace the fuel pump\fuel relay\fuel filter because It wasn't getting any fuel to the engine. Well, It finally turns on, but the engine is very accelarated. As soon as I turn on the car, the RPM idle jumps to 25000 rpm and continues to 35000 rpm all on its own. I replace all the vaccum lines and cleaned the throttle. It remains the same. I am a new porsche owner. I need any I can get.
Thank You.

 

Geez...I don't know.

That early model has the CIS type fuel system doesn't it?

If so - maybe the start valve - or the warmup valve?

Hopefully Dennis will chime in here.

 

The idle adjustment is located behind the thermostat housing and in front of the intake spider. It sits pretty low in there under some vacuum hoses. Its a big slotted screw. The head on it is about the size of a nickel. I adjusted mine just last week. Dont recall which way I turned it to idle it down. But give it a shot. At this point its worth a try. You might want to check the timing with a timing light just to see if your in the ballpark. Check the sticker on the top of your airbox to get the specs. Mine is 31 degrees before TDC.

Good luck.