RJL1417

Hello,

I have a 1981 Porsche 930 Turbo that until yesterday was running really well. Today it started to struggle under boost. It had started to have some difficulty starting the odd time this summer, but it would always eventually startup and smooth itself out. But today as the revs climbed it would stutter and puffed some black smoke out. I noticed when I parked it at home that it smelled like gasoline. Previously the car had sat for a number of years with minimum use. It had a fresh engine rebuild during that time, and before I began using it this summer I had it completely gone through by a local Porsche garage. Like I said it had been running flawlessly until now. Any ideas what has gone wrong? Am I looking for something as simple as a fuel filter and fuel accumulator replacement or fuel injection tune up? Also its a Canadian Car and I am located in Toronto, Ontario.

Thanks for your help in advance!

MUSSBERGER

Check the fuel pump relays and their contacts. Some of the cars will run (poorly) on just one pump
Make sure the metering plate is not getting held open. (could be where you gas smell is coming from)
Check for boost leaks.

I sure others will have ideas as well

RJL1417

Thanks for the reply. Will look into it and let you know how it goes.

bpu699

Agree with checking fuel pump and relays... Most likely cause...

If you don't have an afr gauge, get one. Absolutely mandatory for diagnosing running issues...

Mark Houghton

Boost leaks would be the first place to look. If you have a leak, then when on boost you will see extremely rich conditions and result in your symptoms. Look first at the obvious and easily accessible.. O'ring for the IC connections, then go from there.

I have run with only one fuel pump before I figured out it was a problem. I did not see your exact symptoms, other than not getting full boost and having an issue with cold running performance and overall lack of power. Typically a drastic stumble/flubber/loss of power when on boost and coupled with black smoke means a waaayyyy rich condition. An air leak will cause that with our antiquated CIS fuel system. That's the first place I would look, spend an hour pulling the IC and checking the o'rings as well as the hoses post-turbo, and any and all vacuum line hoses you can get to.

TT Surgeon

Agree with mark, you got a boost leak.

RJL1417

Thanks everyone!
I am on holiday for a week but when I get back I will follow your advice. Another note, the engine temp didn't seem to rise at all. I always let the car come up to temperature before straining it but it never seem to get up to normal running temperature. Also, when the boost came on the gauge would flutter so it could very well be a boost leak. My thoughts immediately went to something with the fuel system.

I will keep you up to date.

Thanks again

Shemmer

Any recommendations on a decent AFR gauge? Would love to get one.

paulleslie

In my experience its the rear of the 2 fuel pumps that fail. They usually become intermittent by showing up their failings when just coming on boost when fuel demand is highest. Causing fuel starvation.This is also intermittent at first. Then more frequent. These pumps can be origonal to car and thus 30 plus yrs old.
The only way to check this easily is to swop with a known good pump, unless you have a good shop with pump pressure test facilities .
Good luck
PS all the other guys suggestions are still valid.
Paul

TT Surgeon

Fuel pumps are another possibility for sure. Also check over on pelican, very active 930 board.

ereedca

What did you ever find was wrong with your car? I am having the same problem to a T.