sometime it starts, other times it doesn't
 

Here's a problem I have with my 944.
It's a '88 2.5L, automatic trans, non-turbo.
I'll start and run it for a while. But go back about 30 minutes later, and it won't start, not even turn over or any clicking sound.
Then maybe about 30-60 minutes later I'll try to start it, and it turns over.
Does anyone know what's wrong and what needs to be done to no longer happen?

Carfreak, there are smarter folk on here than me, but I’d be looking at the ignition switch, but I’d also be checking all the battery AND ground connections.

Best of luck, John

I’m in the same boat as John...haven’t had this problem. One other thing that could possibly cause this though may be a hot starter. Is your starter heat shield in place? I did also have a similar problem with my 951 when the DME to sensor wires were failing. It would stall out when it heated up and go back 30 minutes later and fire up no problem.

If nothing is happening when you turn the key: No click, no dimming lights/voltage drop just nothing, that's probably electrical. The wiring behind the starter and the ignition key switch are always suspect. I do not recall if there is an interlock that could also fail, on an Auto I would try wiggling the shifter and also trying in neutral, and wiggling the shifter in the neutral area.

Could also be the starter solenoid, maybe it can fail and not draw any current.

If you get a click and/or voltage drop when the key is turned I'd look to the starter.

-Joel.

Battery connections, ground straps, starter solenoid cashed, the list goes on..

"One of the first signs of a failing DME/Fuel Pump is difficult hot starting. Quite often when the DME/Fuel Pump relay starts failing the car will start without problems when it is cold. However, when the car has been operated at normal operating temperature for a while, it will refuse to start when the car is shut down and re-start is attempted while the car is still warm. After the car is allowed to sit and cool for some period of time (usually 30 minutes to 1 hour), the car will again start without problem.

If you experience hot start problems, try making up and installing a jumper for the DME/Fuel Pump relay (FUEL-05 under "Emergency Repairs") to see if it solves the hot start problem. Realize that you must attempt this while you are experiencing the hot start problem for the test to be valid."

Troubleshooting - Engine

Good info, but the DME relay is not related to a problem where the starter is not turning the engine over at all.

Once the engine is rotating if it's not starting the DME relay is a great place to look for a problem.

Fair point.

Start with a battery load test.

I am having a hot starting issue as well but as stated above I have learned the slow hot start will still have a spinning starter, it just won't fire off for 4-5 seconds. I replaced the relay and have a slight improvement, but still kinda there. I replaced the fuel filter, plugs, cap, no big improvement.

I was surprised with a battery issue recently where it was reading decent voltage not running/ and while running, but the battery was pretty much gone. Also had issue where battery cable to starter was corroded, and that caused a no start intermittent issue

If your starter isn't spinning at all I would guess either bad electrical connection through the cables, or fuse related if your ignition switch is functioning without issue.

Carfreak: any luck solving your problem yet?