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Warm starting issues

marsh

New member
Joined
28 Aug 2017
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Morning everyone,

I've recently bought a 1978 SC from a well respected Devon based Porsche specialist. It's a lovely, original example that came over from Japan around 4 years ago.

I am delighted with the car overall, but I'm having some warm starting issues of late; which seem to be getting worse. Once the car is warm, it fires on the first turn of the key and then immediately stalls; the only way I can get it to start is by flooring the throttle and hoping the car will catch; something I'm obviously not keen to continue doing. Once running, the car then runs like a Swiss watch, though over the course of the weekend, this approach appears not to be working so successfully.

I've read on other forums that this could be the fuel accumulator, but I'm not so sure. One thing I have noticed is that on the key fob is a Porsche immobiliser of 1980's vintage. I can't see where this is meant to go and in the 3 months I have owned the car, I haven't yet used it, but can't help feeling that it might have a part to play. Could this be a factor in the car not starting and if so, where do I plug it in?

Any suggestions would be very much appreciated before I approach the dealer this week for a resolution. Mindful that I live around 250 from the dealer, I am keen to find a quick resolution if I can; the car is due to be at the Goodwood Revival in 10 days from now, so I'm under a little pressure!

Best regards

lee
 
Im kinda doubting the fuel accumilator ..

Im not an expert on these but its a mechanical fuel injection system .. warm up regulator or temperature sensor are possible faults but really it needs a pressure check at set temperatures to see whats faulty.

Cold start injector is only there for first start .

You could check that at the warm up reg you have 12 volts engine running but for everything else then you need equipment and data .

This is not really home diy and if you are taking it to an OPC then i would certainly phone them first to see if they can do these .

Im only now learning about them at my Indy 10 years at OPC and i never learnt or touched them .
 
You need to find someone that knows the k-jet CIS injection system well (I doubt any OPC will give satisfaction).

I have some experience having both an SC and a 16v mk2 Golf and there is some good info online.

Have experienced hard warm starting on both these vehicles over the years, with the SC it was the fuel distributor head and on the golf it was the fuel accumulator so testing it to reach a diagnosis is better than throwing parts at it.

Things that come to mind to check (assuming you have the ability) are:

Test the fuel pressure in the system when the car is cold and then when warm, fuel accumulator should hold this pressure in the lines to the fuel head for something like 40mins.

Check fuel injectors are not leaking away the fuel pressure into cylinders during hot soak.

Fuel pump check valve (outlet of pump in the banjo fitting).

Emergency fuel cutout switch maybe sticking when warm (located in rear of the airbox). Can you tell if when hot the fuel pump is working, and does the car fire and run for a few seconds and then seem like it's run out of fuel. The pump is quite noisy so have someone crank her over and listen under the front of the car.

I doubt your warm up regulator is faulty as it start from cold.


Report back findings and good luck.
 

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