Johnragno

GothingNC

Could be an issue with the CDI

theiceman

or ignition switch ?

groovy dude

I doubt it's the CDI or switch. Could be either the coil or the relay though, although if it's the coil in my experience it should fail completely pretty quickly. Test for a spark, if there's no spark then it's likely to be the coil, if there is a spark I would change the relay. Also, check and make sure the relay is seated properly, if it's loose it could be your problem.

gdogg16

Check the wiring at the fuse panel for corrosion. Look for discoloration on the fuses as well. If corrosion is found on the wires, cut them back to clean copper and reinstall. Corrosion will increase resistance which will cause the fuses to heat and expand and lose contact. Had this issue happen to me on my '83. Car would intermittently shut off while driving only to restart a few minutes later.

Mark Salvetti

Do you have to wait at all before it will restart, or does it restart immediately after it cuts out? Then how long does it run before it happens again?

Mark

Johnragno

Johnragno

theiceman

my son is in IT so i am never showing him this lol

Mark Salvetti

This is a long shot, but sometimes these weird engine shutdown problems are the rev limiter relay behind the fuel gauge. Just unplug the white wire connector. Check out this thread for pictures and a location: http://forums.pelicanparts.com/porsc...h-version.html

I don't think it would restart immediately if this relay was your problem, but it is so easy to disable it's worth a try.

Mark

aaron.finch

i don't know why its happening as i need to turn key to re-start.

anyone from you can advice me please. at this moment i feel very much bore for that.

Edward

This sounds like an electrical bugaboo: like it's working or not, nothing in between, correct?

1. Hey gurus, do the Motronic SCs have a DME like the 993s?
To the OP, this is a typical failure of the 993 DME relay, many have experienced it (I have, on the road!!), and reason enough to swap it out for a new one as it is a cheap and easy first shot at troubleshooting …if the 83 has a DME, that is.

2. With the car on, I would wiggle and tug at all your relays in the fuse box as intermittent issues often arise from aging cars and loosening/weakening electrical connections.

3. While you're at it, yes, wiggle aggressively the key switch and area. Long ago a buddy of mine had a Bug that this was the very problem. Replaced the ignition switch, and all was fine. Dunno if this translates to a 911, but it's free and worth eliminating that fault.

4. Mark is absolutely right on about the rev-limiter relay (that was, in fact, the problem on my 82 sputtering at random times at random RPMs ...thanks again Mark!!), But as a rev limiter, I doubt it would just cut your engine completely as yours is, but heck, it's too easy not to try, so by all means, disconnect the molex plug to that relay and see if your issue goes away.

Edward

Starbuckslova1

It sounds electrical

Check the tightness of the fuel pump relay new ones are slightly smaller

Feel it for heat is the pump drawing more current
Looseish wire by the pump

Maybe even rev limiter.