I had driven the car for about twenty mins in normal city traffic parked ran an errand got back in turned the key the starter cranked for a short while and nothing happened ....so removed the key and then tried again it turned over and over for quite a while and then fired ....ran normally , no roughness or anything it has never done that before.... drove it all weekend with a few brisk country runs and its not happened again.... any ideas?

 

more data would help a lot. age of battery,cranking over normal,DD ?

 

Battery Harness is known to go bad on the 997.1. Symptoms include difficulty statring when the engine is hot. Search threads. Plenty of info assuming your battery is in good shape.

 

+1 on the harness.
Cable gauge is increased.

 

it may be just me but sounds like the OP meant it cranked normally, it just didnt start. harness issue makes it crank slow.

FWIW after mine was put back together at the body shop last fall, they could not start it either - cranked fine but would not fire. turns out it the ECU wasnt getting a signal from the crank position sensor (??) or something. without that sensor reading, the ECU will not allow the engine to start.

 

battery is about 18 mths old and it cranked over normally, weekend car but used every weekend does about an average of 10,000 kms per annum

 

Thanks I'll look into that

 

Someone already mentioned the crankshaft position sensor.

My contribution would be to suggest the fuel pump or fuel pump relay.

 

Your symptoms suggest that you have higher resistance in your battery cable that leads to the starter. It's an extremely common issue with the early 997.1 cars. Sadly, while the battery cable is relatively inexpensive in the grand scheme of things, replacing it requires a fairly exhaustive engine disassembly (intakes, etc.) While not impossible to do, it does entail some work.

Many dealerships will replace them if you are within the Porsche warranty period if the resistance is greater than .5 Volts.

 

If tried to push my dealer to replace mine under CPO but they didn't budge.

 

I have not had it happen on my 997, but on other cars if I were to attempt to start the car (like just bumping the key) and it didnt start the first time, the second subsequent start took a lot longer. I suspect it is the computer checking things. Not sure if it is a theft think (like in the case of a "hot wired car"). But definitely took longer to start after but no other issues. It happened in the exact same way several times.