Porsche 996 cranks but will not start

[Paulnico]

Hi, thanks for your thoughts, all ignition lights come on, air bag light goes out after 3 secs engine turns over at good speed lights drop off while cranking, just will not fire, but I can smell fuel from the exhaust.
No light in glove box.

[Huskyman]

Paulnico said:

Hi, thanks for your thoughts, all ignition lights come on, air bag light goes out after 3 secs engine turns over at good speed lights drop off while cranking, just will not fire, but I can smell fuel from the exhaust.
No light in glove box.

It sounds like the immobiliser has developed a fault and isn't giving the DME the correct signal to start the car, IIRC most immobilisers will do more than one circuit, so you are able to turn the engine over, it's getting fuel but no spark. If you have access to the wiring diagrams for this car I would strongly advise checking the grounding points near the DME, and the immobiliser for any corrosion.

Do you have access to an oscilloscope, and a laptop with the diagnostic software on it?

[ooid]

Did you check this video? Although his car does not crank..

https://www.youtube.com/watch?v=hND_6Q_-Q4w

My 986 did a very similar thing a few years ago while in the service actually. It was something to do with immobilizer and ECU, a specialist had to sort out not sure about the details sorry.

[Paulnico]

I decided to take it into a local specialist, and the diagnostic indicated that the fuel injection was inactive, after another 2 hours of testing, they called me up with quote to replace the fuel pump, I will report on the outcome in a day or 2. The quote including diagnostic, pump, labour, vat is £850 wich is a painful hit just before Christmas.

[edc]

Paulnico said:

I decided to take it into a local specialist, and the diagnostic indicated that the fuel injection was inactive, after another 2 hours of testing, they called me up with quote to replace the fuel pump, I will report on the outcome in a day or 2. The quote including diagnostic, pump, labour, vat is £850 wich is a painful hit just before Christmas.

Sounds expensive. Same fault find remove and fit new fuel pump on my 986 was 3 hours plus £200 for pump. I had a few other bits done at the same time and still came in £300 less than your quotation.

[ooid]

Fuel pump is about 350-400 GBP for 996 turbo. I guess, the labour and first diagnostics costed a lot.

[Markbarry1977]

Did the fuel pump fix it OP?

[strath44]

Another bump on this thread for the OP to reply - I have the same issue!

[Armut Schweinefleisch-911]

Please forgive me piggy-backing on this thread but any suggestions on a decent DIY friendly OBD code reader?

There's a great manual on Amazon for £20 or so called 101 Projects for your Porsche 911 996 & 997.