911 sc rarely starts first time. Always second try

[Jowniofownio212]

I have no means of testing the fuel pressure and don’t know how to test the CSV. No matter if the engine is hot or cold, the car only starts on the second attempt. This is even if I try to restart it 10 seconds after shutting down. 

Eg, I thrash the car for 10 mins. Stop it, then try and restart it and it won’t start first time even if I keep the key held for 10-20 seconds. My starting process is try to start it for 2 seconds, then ignition off for 5 seconds then second attempt and 9/10 times it starts straight away. 

 

If if I link the fuel pump to run as mentioned above, it starts first time every time. This is where I think there is a loss of pressure for starting.

 

its booked into the garage next week as I cannot test the fuel pressure my self so will keep you informed

[Phill]

Mmmmm..... I'm starting to think dodgy starter solenoid.........

[hotfrog]

If you are measuring the 10V at the relay when the engine is cranking that would be normal due to the high demand of the starter motor dragging the volts down.

[Jonny Hart]

^what he said...

Just to add.  On an SC, the fuel pump should ALWAYS run when the key is in START position (engine cranking)  

The air flow flap switch only prevents the fuel pump running if the key is in the RUN position (engine started). 

Edited August 25, 2019 by Jonny Hart

[Jon Miller]

I suspect you have no power to the fuel pump on cranking. Get someone else to listen to the fuel pump as you spin the engine on the starter.


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[Jowniofownio212]

Problem solved. Was a strange one!

The starter motor was full of gunk/carbon deposit and one of the internal spacers had fallen to pieces so it was being massively restricted and pulling all the battery power. This has been repaired and the starter spins noticeably faster and isn’t draining the battery and it starts now first time!

Thanks for all the help

[jevvy]

Excellent result - thanks for posting the outcome.