bad starting when hot

[majorporsche]

My technique with older 911's is gently depress the accelerator fully then hold it open and crank til it fires.

 

[Hardy911]

Hello
I am interested in a SC coupe 90K miles 82
It all seems realtively ok but the engine is a real pain to start when hot .
Ok when cold no blue smoke and no black rich mixture signs .
I thought I would ask on here to find out what I might be in for before going any further
Any Ideas appreciated .

 

[Old and Slow]

With my SC, the first turn of the key cranks the engine, I release it after a couple of seconds, then I gently depress the accelerator to keep the throttle open and it usually bursts into life immediately on the second turn of the key. If the car starts OK from cold and runs OK then the fuel pressure, fuel pump and its relay and the fuel filter would all appear to be OK and the ignition must be OK too, so the problem is likely to be somewhere else. The power to the fuel pump is a bit complicated; if the airflow sensor plate is sticking (when hot) then it can prevent the power going to the pump relay. The way to test this is to remove the air filter housing and turn the ignition on, and then lift by hand the arm that goes to the airflow sensor plate; as the airflow sensor contacts close you should hear the fuel pump running. Hope this helps.

 

[Hardy911]

Thanks for that will try it and report back

 

[oilcooled]

The K jetronic had a pressure accumulator in the left rear of the engine bay if faulty it could let the fuel pressure drop when hot causing bad starting.