85 Carrera occasionally shuts off

[Rusty 356]

Full tank of fuel, cruising about 60 mph the engine just shut off eventually dropped to second gear and car fired up an ran normally. Has done it twice since when coming to a stop the engine died at idle and started immediately with the key. Crank sensor?
CD box? Any one have the same experience?
Thanks and have a great day

[SalParadise]

Any of those issues I have had it was the crank sensor. It seems yours is on the way out. Replace it before you stall in an intersection or in the middle of a road somewhere. They are a PITA when they fail, but they usually begin to exhibit the symptoms you describe when they are hot with an up to temp engine. They are fine when the engine is cold, but when it warms up there is trouble.

[Rusty 356]

Sal thanks, this morning same thing runs for about 5 minutes, shuts down, waited about 5 to 10 minutes started back up and now I’m waiting for a restart.
Will change out sensor today. Thanks
Rusty

[old man neri]

If you're going to change the crank sensor, change out the position sensor as well. Two sensors that are identical and next to each other.

[Rusty 356]

Been waiting, she’s done. Starts for about two seconds and dies. Dang!
Rusty

[Rusty 356]

Thanks guys, have both sensors coming. After about a 15 minute wait she started again and got me to the shop.
Will post results later.
Thanks,
Rusty

[93nav]

Not to highjack the thread, but would any of these solutions apply to a 1976 911S, North American? I started having close to the same problem last fall, though it would cut out just briefly at speed, but not quit. It did quit outright while at a stoplight just before I put it away for winter. Started right up though. Happened a total of about 7 times.

The car is stock, still with points, the alternator was rebuilt locally about 1000 miles ago. I plan on polishing up the fuse contact points before I start the car again for spring. Probably at least two weeks before streets are clear of snow so I can drive.

[SalParadise]

Originally Posted by 93nav

Not to highjack the thread, but would any of these solutions apply to a 1976 911S, North American? I started having close to the same problem last fall, though it would cut out just briefly at speed, but not quit. It did quit outright while at a stoplight just before I put it away for winter. Started right up though. Happened a total of about 7 times.

The car is stock, still with points, the alternator was rebuilt locally about 1000 miles ago. I plan on polishing up the fuse contact points before I start the car again for spring. Probably at least two weeks before streets are clear of snow so I can drive.

No, your car does not have the same ignition or any flywheel sensors.

[Rusty 356]

Update, replaced both speed sensors last week but while on the lift decided to do a little emergency brake work. Yesterday put her back on the ground, started and ran with no issue, but quit as soon as I was out of the shop and didn't restart. Had a spare DME relay in the glove box, replaced the original one and started up no problem, but in moving the relay back in place the engine cut off, seems anytime I move the relay around or mess with the wires she quits, I did drive her home and will bring it back in and remove the driver's seat and see what wire is giving me the issue. Will keep you posted on findings.
Enjoy the day,
Rusty

[Ydobbs]

I had a very similar issue with random stalling/no start - turned out to be the DME itself - old cracked solder joints. If I wiggled the DME plug just right I could get it to start. Had the DME inspected/repaired and it hasn't happened since.

[Rusty 356]

Definitely DME circuit related.

[DRACO A5OG]

+1 get DME unit checked. Steve Wong can fix you right up