912E wont idle!

[PorscheDV]

ok..heres the situation...it ran fine, but i had someone do some adjusting in an effort to make it pass smog...now the thing wont idle..but only intermittantly, and it seems completely unrelated to temp...

ill start it up and it'll idle just fine...i'll leave...and a few hours later it'll start but it wont want to keep its idle, it'll try to idle like at 400 RPM while hesitating and stumlbing...

it'll run if i keep RPMs up.. but i want it to idle on its own..i feel like if i up idle it'll run high at times (when its running like its supposed to) and just right (when its supposed to be idling low)

(oh, even if i do adjust idle...how do i do that...what does that big flat head screw, (about half an inch dia) do? its right next to the throttle linkage..)

im open to any suggestions! thanks guys...

[ScotMcLean]

I don't know how to help you except say contact:

Mark Allen at allaircooled@yahoo.com

He is Oceanside north of San Diego and knows the 2.0 well - he may know someone who can help - Scott

[david c.]

This might seem goofy, but I've read that the seal on the oil filler cap has a role in a choppy idle on the 912E. My car has been converted to Webers, so I can't say for sure. But, I have read this and it is easy to check for. Good luck.

David

[WFBowen]

PDV: I'd do the following. On the airflow meter, there's a small flat screw under a black plastic cap. The screw head is small and sunk into about a 1/4" deep hole. Turn this out 1/4 turn at a time - this is the idle mixture screw. If you've already passed smog, you can go an additional turn out - it's hard to get a "too rich" idle mixture with this setup. That large flat screw by the throttle linkage is the idle air adjustment (idle speed.) Turn it out 1/4 at a time.Disconnect the return spring & check that the throttle valve is not binding. Also, check absolutely everywhere for vacuum leaks (incl. oil cap) and all vacuum lines, fittings, etc.& the 4 air intake runner connector hoses. The large air intake hose (airflow meter to throttle valve) tends to crack on the underside after many years. Now check the auxiliary air meter which is on the pass. side of center, opposite the distributor. Block off the air line going from it to the large air intake hose & see if it makes a difference. Double check the distributor timing, especially check that the vacuum retard diaphram on the dist. holds air.Hope this helps.

[WFBowen]

CORRECTION TO ABOVE...On the airflow meter adjustment screw, screw clockwise (in) to richen mixture.....sorry, I had a brain fart from the "Holley" side of my brain.

[josh912]

How's the timing?? He could have backed it off to pass smog.

------------------
Joshua Harrison
Porsche owner at heart

[PorscheDV]

YEAH! you guys rock..i wont have time to do it today, but i should have time tomorrow...i'll give all those suggested a try and let you guys know how it went...

THANKS AGAIN!

[nige]

make sure your oil filler cap is tightened firmly or losen it with the engine running you'll notice the engine idle alters. The engine runs an air tight system I think, anyway it worked on mine when I changed the oil, it didn't idle at all until I tightened the oil filler cap!!