‘85 Carrera engine quitting

[Ttrammell_58]

Engine stopped suddenly after driving about ten minutes. No indication of anything wrong. Re started after 10-15 minutes and drove home. Ran it in the driveway and happened again with shorter run times before quitting as outside temp increased.
First thought was DME relay or CHT probe. No start more common with bad relay, but had one on hand, swapped it and ran for 15 minutes with no failure. Figure it had weak solder joint that opened up after warming up. FWIW

[PopsRacer]

pardon me if I’m a day late and a dollar short here,

I just got finished chasing an intermittent no-start/stall issue on my ’88 3.2. In the end, the 2 culprits were the DME relay (I reflowed the solder joints and replaced the 1Nxx diode which had a bad internal connection) and then replaced the fuel pump.
If it runs and then quits I would definitely look at the fuel pump. You can hotwire it at the fuse panel with the car “off” so you can listen to it. (This trick is in the Porsche factory manual so it’s kosher). Mine sounded like it had shredded metal inside and it started and stopped at random. If I had checked it, or my fuel pressure earlier - it would have saved me a flatbed ride. I didn’t have the right pressure fittings to check it, and the car started and ran (mostly) so I didn’t think about it. Now I have the right tools (lesson learned!)
I was able to ID the DME relay because it died while I was driving and the tach went to zero (while the engine was probably turning 3k rpm); it was clearly an electrical thing, like someone threw a switch. I kept the original as a spare and installed the Focus9 solid state unit with the diagnostic LEDs.

[blueline]

pardon me if I’m a day late and a dollar short here,

I just got finished chasing an intermittent no-start/stall issue on my ’88 3.2. In the end, the 2 culprits were the DME relay (I reflowed the solder joints and replaced the 1Nxx diode which had a bad internal connection) and then replaced the fuel pump.
If it runs and then quits I would definitely look at the fuel pump. You can hotwire it at the fuse panel with the car “off” so you can listen to it. (This trick is in the Porsche factory manual so it’s kosher). Mine sounded like it had shredded metal inside and it started and stopped at random. If I had checked it, or my fuel pressure earlier - it would have saved me a flatbed ride. I didn’t have the right pressure fittings to check it, and the car started and ran (mostly) so I didn’t think about it. Now I have the right tools (lesson learned!)
I was able to ID the DME relay because it died while I was driving and the tach went to zero (while the engine was probably turning 3k rpm); it was clearly an electrical thing, like someone threw a switch. I kept the original as a spare and installed the Focus9 solid state unit with the diagnostic LEDs.

Much appreciative of the feedback and analysis.

Welcome to Carpokes!