Erratic Idling Problem cont.

Saffs · 12-08-2001, 10:56 AM

Briefly, I'm just back home for a little while, and my 911 is idiling erractically - after being standing 3 months; usually fine after this, I do it often. Been on a long journey (200 miles) and I don't think my gas is bad. Car is fine accelerating but idles anything from 0 revs to 3,000. When idling badly it has grey smoke coming out and sometimes gets a little better- idling.
OK. I've pinned down that on testing for a live 12 volt at the WUR on my 2.7 CIS with a test light - no voltmeter avail. - reveals no live there. That is, connecting a test lamp to the two wires going in to it and earthing the other end of the lamp both show no live. After searching on the BBS, I found that if the WUR has no live, the Aux valve doesn't and it will idle high and erratically running over rch too.
So, is this correct? Furthermore, where does the live for the WUR come from? I think it come from the fuel pump relay - engine bay I guess, maybe damp there??
I need the car for daily use whilst here is this really annoying.
TIA

Superman · 12-08-2001, 11:17 AM

Sounds reasonable to me. Certainly, if the WUR is not getting voltage, then the mixture will stay rich.

Saffs · 12-08-2001, 04:18 PM

Just to add - and bump - how should one test the voltage to the WUR? I'm guessing just how I did it, with a test lamp and prodding in to the plug going in to the connector of the WUR - there's two prongs - and I was running the earth to the body of the car, but if I'm wrong....

Bob Goding · 12-08-2001, 09:50 PM

Saffs--I might get flamed for this ,but I had that horrible hunting idle on my '76 2.7 and cured it with a new battery!!! The voltage
regulator had gone bad and cooked the battery. It would start the car alright.----New bits solved
the problem for me.----and you did say the car had been sitting for awhile----cold too ,I assume.
Bob

Saffs · 12-09-2001, 01:09 AM

Quote:

Originally posted by Bob Goding
Saffs--I might get flamed for this ,but I had that horrible hunting idle on my '76 2.7 and cured it with a new battery!!! The voltage
regulator had gone bad and cooked the battery. It would start the car alright.----New bits solved
the problem for me.----and you did say the car had been sitting for awhile----cold too ,I assume.
Bob

Thanks Bob.
That is a good point. My battery is 8 months old, and the car is charging fine. I know that a dead cell in a battery can cause poor runing.
Thanks again.
I'm going to go through everything again now it's daylight. Anymore assistance would be great as the car is almost undrivable and it's looking like rental car time....

Saffs · 12-09-2001, 09:09 AM

Thanks for your help everyone, fixed the problem. It was a fuse, presumably, and I hope, feeding the WUR and Aux. air valve so the car was running rich al lthe time. Cleaned it up (the fuse holding) after spotting it wasn't feeding the WUR.
Cheers.

speeder · speeder's Garage

Anytime you can fix a bad-running Porsche for under $1.00, this is a happy day!