Re: Crank position sensor...had the same problem!

I just wanted to document a couple of gotchas for those who work on their Porsches. These two are off the top of my head, I'm going to go back through my maintenance records and see what else I can remember. Anyone else have any gotchas they can contribute?

Note: These were discovered with my MY99 986.

1. If one of your oxygen sensors is shorted, short circuit codes for all four sensors will be thrown. You have to find the short by manually inspecting the wiring for all four sensors.
2. You may not receive any code/CEL when your crankshaft position sensor fails. While troubleshooting a no start issue (engine cranked but didn't start, as if out of fuel) I tested my CKP sensor with a multimeter and discovered values totally out of spec. You'd think that a sensor which fails an electrical test so badly would trigger a CEL. Nope. Sensor is replaced now and it runs like a charm.

Edited 1 time(s). Last edit at 08/06/2015 04:54PM by Jayusa123. (view changes)

Yup, I had the same problem. Note also that it's not just a "doesn't start issue". It can also cause a running engine to stop running. In the early stages of (intermittent) failure the engine will eventually restart after some period of waiting. But the problem progresses quickly so it's best to jump on it.

Grant

gee-lenahan-at-gee-mail-dot-com

Car died after 15 minutes, right when we were crossing a small bridge on Longwood Ave at the Harvard Medical Area. Some genius then tells us "Hey, you can't park there."
Buddy...are the hazard lights blinking too fast for your brain to register its meaning?

...



Edited 1 time(s). Last edit at 09/08/2015 11:20PM by RainyDayGarage. (view changes)

Hello... back from Italy, time to tackle the Crank position sensor. Although I am not certain this is the problem... no error message to confirm. How difficult is replacement of the sensor?
Appreciate the insight.

You'll just need to jack the rear of the car up and get under the car (to the right of the engine) on a creeper. There's a testing procedure you can complete with a multimeter:

1. Remove connector.
2. Connect ohmmeter to CKP sensor connector, pins 1 and 2. Should read 0.8 - 1.0 kOhms at 68 degrees F.
3 .Connect ohmmeter to pins 1 and 3. Should have no continuity (Infinity Ohms.)

I found it easier to complete from the top of the engine through the access panel.

Good luck!

Jay

As Jay said, it's unplug, unbolt, pull out, reverse.

However for my 1999 the bolt was frozen and I had to "convince" it to come out. Then the bolt was in no shape to be reused. I took one of the ignition coil bolts, cut it down to size and used that.

It's in the center of this photo (click to enlarge)