hot starting problems / fuel starvation

[Guest]

Hi I have a 1974 911 with bosch k-jetronic fuel injection with hot starting problems / fuel starvation. If left for more than 15 mins it won't start, after 3 hours its ok. The only method I know to start the car is to "bleed the system" by taking the air filter off and turning the starter key on and pushing up the air meter plate. This seem to flood the engine a bit but then it starts. Obviously this is very annoying and not very Porsche like.

Looking forward to salt free roads
Pete

 

[peanut]

sounds like your fuel rail is getting too hot and vapourizing the fuel .
You might look at adding a heat shield to protect the fuel rail and inlet area from the exhaust manifold heat and also check that fuel is not returning to the tank every time you switch off.( fuel pressure valve )Also see if you can improve air flow to the area
, might be worth looking in the racing parts catalogue to see how they deal with the problem
Assume you have already checked ,fan/s temp sensors and temperature after switch off

 

[912UK]

not saying it's the answer but well worth doing from past 912E ownership and the research I did..

take the starter motor wires off clean them with sand paper and put back, do this to all conections and then follow and check and do the same on the earths..

I hope then it will work for you before you start to strip the car down []

 

[petercook]

Hi Pete,

Only just got around to reading this thread - sounds to me like the fuel pressure accumulator that is in the circuit specifically to maintain pressure on a hot engine. It can be found just after the fuel filter in the engine bay. If this little box of tricks has never been replaced on your engine this is probably the cause of your problem.

PJC

 

[wblackw9]

Try the fuel pump first it could need a new none return valve put in the end. Its the cheapest route i actually have one depending on the pump you have, if its the one with the long neck then i have one. You may also need a bigger banjo union tho. Let me no at wayneb911@yahoo.co.uk call it £5 plus postage? if needed. if its not that at least its the cheapest eliminated, could then be warm up reg or accumulator. Try Ken mills in London for a rebuild on the warm up reg £122 all in and posted back, £85 acumulator design 911