S500L W220 1998 INTERMITTENT NO START

[porscheplus.co.uk]

Hi,
The car runs fine and starts well, however recently when warm it has failed to start so far twice, it has done 110,000 miles.
The starter motor will turn the engine until it times out, it sounds like it is out of fuel, it is not I checked. Called the AA and they reckoned it was a sticking fuel pump, they banged on the rear boot wall while cranking and it started.
It then started 5/6 times without fail, we put a new fuel pump in assuming that would cure it. Ran it for a few days and the same thing happened again, from warm. I swapped the fuel pump relay but it made no difference. eventually after thumping the boot wall several times it started.
I wonder if that is just coincidence and a faulty part has cooled down and reset itself.
Any ideas?

 

[alexanderfoti]

Sounds like a common crankshaft position sensor failing. They go when they get hot. Common time is when sitting in traffic, or stopping after a long journey, for it to then fail to start.

£40 pound odd part. 1 hour labour to change.

When they go cold again they function normally.

 

[Pathfinder]

As above, crankshaft position sensor is my bet.

 

[shine]

Same thing happened to my S500 a new CPS fixed the problem.

 

[television]

Yes CPS, mine went on the 216 and £26 from MB and ½ hour to fit, some are pigs to get to and the Bosch versions can cost £100.

Fine when cold but stopped all the time when hot

 

[alexanderfoti]

Yes CPS, mine went on the 216 and £26 from MB and ½ hour to fit, some are pigs to get to and the Bosch versions can cost £100.

Fine when cold but stopped all the time when hot

Welcome back Malc! Good to see you!