Chris Hansen

So, today while running some errands, I hope in and start the car and it immediately dies. After restart, the car runs fine, but only if I keep my foot on the gas. I made it home in stop and go traffic, and a few miles on the highway, but it will not idle. If I let up front the gas, it dies.

Any ideas? Couldn’t find anything with a quick search. 1981 928.

Thanks,

Chris

Chris Hansen

Quick update . . . Today I go out and start the car, and it is idling perfect. Multiple starts and driving until warm, and I cannot replicate the issue.

If anyone has any thoughts, I’d appreciate it. Not sure where to look for the most likely suspect.

Side note . . . Looks like my membership has lapsed! I’ll get that taken care of . . .

Thanks,

Chris
1981 Porsche 928

Bulvot

For what it's worth, I had similar symptoms on my '87. It turned out to be a blockage in the intake. Mice had built a nest on top of the MAF screen, under the air filter, practically overnight.

Let us know if you find a root cause. It would be interesting to know.

Chris Hansen

Thanks, Bulvot. I’ll check for any oddities/critters.

I’m kind of wondering about the green wire. Was thinking it was pretty new, and then realized it was replaced 12 years ago!

The Forgotten On

I had an issue like that as well with my S4 only it would die occasionally at a stop. Turned out it had sucked in a shopping bag and covered 2/3rds of the air filter. Similar to what happened to you Bulvot.

Chris Hansen

Intake is clear, so we can rule that out...

poppydaddy

Hey guys, Poppy here(grand kids named me), New member...and new to Porsche 928 ownership. Mine is a 1985 that came from drug recovery... with ripped out interior and sat in impound for MANY years. Different 81 vs 85 engines but can have similar problem either with no idle or run away idle. Different, but both still have an idle control valve that sticks or rodents eat the wires that operate it in the engine valley under the intake. If it stick or fails close, no idle. If it sticks open, run away idle. I have just completed the Intake refresh for the run away idle about 2500 rpm on mine, stuck open. Didn't find anything wrong or broken just lots of sticking parts. I replaced many hoses and gaskets while I was in there. I recommend cheap mineral spirits (about $10 for a gallon) for cleaning the sticky old gas from your fuel system and intake. It worked very well for me and does not seem to damage anything. Good luck! It is a lot of work to take apart and do this job. I think yours is the 16v engine. I don't believe it is as buried as on the 32v engine.

Poppy

Chris Hansen

Well, I think I may have found the problem. When I went to remove the air filter housing, I discovered that’ all 4 bolts holding the air filter housing horn to the air meter had come loose! Since that’s the only thing holding the air flow meter...

its been a few years since I had it off, so I guess I didn’t do a good job of tightening.

I will report back if the issue recurs.

Chris Hansen

These were the loose bolts.