Porsche Enthusiasts Club Forum

Just thought I would share recent scary experiences with my 1998 996 C2 in case anyone else finds themselves in the same position.

The problem started with a refusal on a couple of occasions of the engine to restart after a run. When left for half an hour or so, it would fire up perfectly.

Things then developed into the engine stopping without any warning while doing 60 mph then refusing to restart for an hour while stuck at the road side (fortunately on a straight stretch, but finger biting none the less).

Doing a fair bit of research of the internet resulted in going round in circles with suggestions of fuel pump or relay problems until stumbling on reports of failing crank position sensors causing the exact symptoms my car was experiencing on other cars mainly in The States. Some of these guys had a fair amount of their money wasted by specialists in guessing which parts were causing the problem until eventually the crank position sensor was changed and in almost all cases the problem was fixed.

Had mine changed today and ran the car for over an hour with no problems. I also tested the old sensor by measuring the resistance between pins 1 and 2, then heated the sensor up with a heat gun. Resistance starts at around 800 ohms when at room temp, but goes mental after a few seconds of heat. Once cooled down, the resistance is stable again.

So if you find yourself in the same predicament, a new Bosch sensor cost about £70 from Design 911 http://www.design911.co.uk/fu/pt259_1352_-cma81-cmo110-ct345/Porsche/996--911--1997-05/996-C2-3-4L-1997-08-01/Speed---Reference-Sensors/ and about an hour to fit after you take off the rear left wheel http://www.pelicanparts.com/techarticles/Porsche-996-997-Carrera/26-FUEL-Replacing_Engine_Sensors/26-FUEL-Replacing_Engine_Sensors.htm.

Thanks for the info, glad you got it sorted

A bit more info for clarity:

If you want to go to an OPC for this, the Porsche part number for the crank position sensor aka impulse sender is 986 606 112 02 and will cost about £150.

Don't get confused between this sensor and the camshaft position sensor. Most internet searches for the crank sensor give many results for the camshaft sensor, but as the name suggests, they are completely different sensors.