E-Man

I have a question for the mechanically inclined. I bought my '77 930 this past January and have put around 500 miles on it since. Six months ago I was driving the car and the engine just shut off. I rolled to a stop and started the car and took off like nothing happened. This didn't happen again for a few weeks. I figured maybe I just stalled the clutch on accident, but no the car would do this intermittently at random times. Best I can describe it is it's just like if you were driving along and turned the ignition off. Now I am noticing it happening more frequently and when I was fueling up at the station a few days ago it took three attempts to start the car, so this is not a good pattern. I would say that the car has shut down on me four or five times total and the last two in the same day. Has any one else experienced anything like this on an early 930. I should mention the engine is all stock with no modifications. thanks

Mark Houghton

Grab a glass or two of your favorite beverage....put a log on the fire...and do some reading here. About the best diagnostic thread you'll find on 930's world wide.
http://forums.pelicanparts.com/911-9...snt-start.html

Then, we'll go from there. Oh, and about being "mechanically inclined".....we all are, it's a prerequisite of owning cars that only a select few know anything about anymore

MUSSBERGER

Could be a number of things but I had a situation like that with my race car. Car just went dead on the track. The keyed portion of the ignition switch can get loose from the switch portion. The two pieces are held together with tamper proof screws which in my case had been tampered with somewhere along the way.

Last930

A common occurrence on these cars is for the fuseholder for the fuel pump fuse to corrode. This causes intermittent electrical interuptions like you are experiencing. Both fuel pumps are run on the same circuit from the factory; many 930's have been modified so that each pump has it's own circuit. If yours has not had this done you might want to consider it.
In the meantime check under the fuse cover for the correct circuit and pull the fuse and clean both contacts as well as the fuse then reinstall.

E-Man

If it was a fuel issue wouldn't the car stutter or run lean before it cuts out? What I'm experiencing is like a light switch turning off and on.

Thanks for all the helpful suggestions so far guys. Another guy told me it could be the over boost sensor gone bad?

Last930

My experience is the engine quits immediately - no stuttering or running on. It takes 5 minutes to check.

E-Man

I'll check it out. Thank you

Mark Houghton

Understand that the over boost sensor cuts out the fuel pumps, not the ignition. That would ordinarily be the first place I would look at, since it's a simple single wire connection that might be loose. That connection goes to ground,and if it is problematic, you could see the symptoms you're seeing. Check it, make sure it's clean and tight. And as already mentioned, anything else (such as the single fuse for the pumps) that might cause fuel stoppage.
No,...when the pumps stop you won't see a gradual sputtering, i.e., leaning out. The car will simple and abruptly stop.
All of this is covered in the link I sent you earlier.

E-Man

I replaced the over boost sensor. Problem solved

MUSSBERGER

I knew it!