964 cut out while driving and would not restart
 

I was out today in my 964 and it just died on me. I tried to restart it and it has power but just won't turn over. Could it be the fuel filter or the fuel pump relay?

The Fuel Pump relay is always the first place to start when it randomly shuts down or doesn’t start up.

Happened to me on my RS America. Turned out to be the Key. Nubs wore down, let Run Pin Open.
Used Spare, Fired right up. Changing the relay didn't help.

Good to know, can’t be common but certainly something to check. How many miles do you have on your RSA?

Check out one of the relay. I forgot the name of that relay, but that relay needed to open up and
re-solder or buy a new relay. I re-soldered it and it works.

Check to see if you have fuel. spark at the plugs.If both are not present, could be flywheel speed sensor.

170k miles. The Ignition Switch on my 1970 914-6 wore out and wouldn't engage the
starter. $600 to rebuild the switch, so they can be rebuilt, just pricy. I used Black Forest in San Diego

Good Luck

Relay
 

If it is your relay you might consider a solid state relay from ftech9 if your 964 is a coupe. For some reason they don’t work on a cabriolet. No affiliation. I went through two relays. I installed their ft9 a few years ago and no hiccups yet. Btw. Always keep a spare.

I would start by checking the fuses to the DME and fuel pump if that doesn't do anything try replacing the DME relay. It sounds like the engine is turning so it isn't the starter.

I have had the switch at the end of the key column fail. It is a PITA but can be swapped out. It doesn't sound like the problem but the switch is designed to cut out the lights and in the case of a C4 or turbo the hydraulic pump when starting to eliminate excessive draw on the system.

Engine Cut Out
 

After Fuel Pump Relay, and Fuses - Next culprit is Fuel Pump