CIS guys - Need help

[totle]

I have a friend that has a 964 turbo engine in his IROC replica 78 model 911.

He has lately had problems with leaking fuel lines from his fuel head.
Ha had made a new fuel line, but it could not hold the pressure when WOT and full boost. The new fuel line cracked open.

He just ordered the original Porsche part (930-110-364-00)
Part #40 in diagram below.



I'm thinking it can be some issues with control pressure, and the new line might blow again.
He has not measured control pressure yet.

What is your suggestion. Could it be some other things to chek?

[totle]

He sent me this video of the leaking fuel line

[JFairman]

That line takes system fuel presure from the lower diffferential chambers in the lambda fuel head and feeds it to the lambda pulse valve. The pulse valve is an inline electronic injector controlled by the k-jetronic lambda box under the left seat. The pulse valve returns fuel to the tank via the return line on the fuel head.

It has nothing to do with control pressure most people are familiar with in the control pressure regulator or WUR.
He just needs the correct high pressure fuel line that can handle the fuel pressure CIS runs at if he's making his own. Or buy a new one from the dealer or wherever.

The lambda system is for emissions and it can be completely removed if you don't need it for emission inspections and then the fuels heads 6 individual injector flow adjustment allen heads that adjust spring pressure on the top of the final metering diaphram that seperates the top and bottom halves of the fuel head need to be adjusted during an injector flow test (tightened a hair) to compensate or it will be too lean.
It's easiest to just replace the leaky hose with a new fuel hose that is made to hold at least 300psi fuel pressure so it won't pop a leak at 100psi.

[totle]

Thank you for great info.
As I remember it was not there for my 78 fuel head, but then again it never had a Lambda or ECU either :-)
Guess this is some of the part that differs the 930 fuel head from the 964 turbo fuel head

[JFairman]

Your welcome :-)
That aluminum lambda fuel head with the lambda frequency or pulse valve whatever you want to call it is also on all 930's sold in the USA from 1986 through '89 so they could pass emissions and sell them here again.