Won''t start when very hot

[johnny7]

First time this happened was when I got the car hot for the emission test at mot- after the test turned the car off while chatting to the mot guy- jumped in car- nothing- wouldn't turn over - dead -as if it had some thermal cut out- 15 mins later- fine started on the button.
I mentioned it to the Porsche garage that services the car and they said that it had happened to them when they moted the car in the past- they thought it could be the crank sensor?
Anyone had a similar problem?- or shed any light one what it could be?
Johnny

 

[ch3tman]

This may be of help... : Hot start issues / vapour lock / something else? [updated]

 

[johnny7]

Thanks for the link- but mine doesn't turn the motor over - there's nothing there when I try the key

 

[decgraham]

Hi,

I've had the same problem. If your car is a manual try bumb starting it. That will prove it's nothing to do with a fuel issue or vapour lock if it starts. I believe it's a starter motor issue. I haven't changed my stater yet but will be doing so when I finally get to the UK for a top end reseal. (Engine out) The other thing to try is to connect another battery with jump leads to give extra amps to the starter motor. I think the problem lies there. I maybe wrong but worth a try. You can also look at replacing the earth straps

Good luck and please let me know how you get on :thumb:

ATB

 

[madalaa]

it could be the crank sensor?

..... that's where I would put my bet ........

Although I did have a similar experience in Spain on a very hot day when I had just filled the tank brim full and it refused to start ....... and I remembered from my V-Dub days that once when the tank was brim full I had a failure to start ...... I loosened the fuel filler cap and the car started ....... did the same on the 993 in Spain and the car started first time ....... :dont know: :?:

 

[ras62]

Try and move the car a few inches in gear with a push and see if the engine turns afterwards. Suspect the starter or earth. Crank sensor does not affect the engine turning on the ignition, it just stops the fuel pump if its bad.

 

[decgraham]

If the problem is the same as mine then the car acts as if the battery is flat. Although all the lights come on, radio works, headlights etc, but when you turn the key nothing. Come back in 30 minutes and all is fine. I just feel it's a contact issue within the starter.

ATB

 

[decgraham]

Just Googled resistance and heat. Resistance increases with heat so perhaps hot contacts poor connection. :?:

ATB

 

[johnny7]

Thanks for all the input- it did have a new starter fitted a couple of years ago before I bought the car- I'll take a look at invoices and service history that came with car-crank sensor has been mentioned by the mechanic that serviced the car- is that a easy thing to get to to change?
Johnny

 

[decgraham]

If you just Google Crank Sensor you'll see a couple of posts on Renlist which should point you in the right direction.

ATB

 

[ras62]

Crank sensor will not stop the engine turning.

 

[Pickled Piper]

Crank sensor will not stop the engine turning.

As above. I read it that the car does not crank when hot. It's going to be starter motor / solenoid or associated connections, perhaps the earth strap.

 

[madalaa]

The starter motor on the 993 is very heat sensitive because of it's position ....... I had multiple failures during my ownership ........ I think I had three replaced under warranty ........ :?: