i was wondering if anyone could help me....i have a 1975 porsche 911 with cis......i just bought the car it is my first porsche........when i first tried to start it....it would start then immediatly die.......playing a round with a few things i notice that if i pinched the fuel return hose it would start and run perfectly.....does anyone know what the problem could be or if there is a valve that is faulty?....and what part i need o replace....thanx

 

http://www.auto-solve.com/mech_inj.htm

I would think that either the warm up regulator (WUR) or fuel distributor relief valve are not working properly. Essentially it sounds like you are not getting system pressure and by pinching the return hose you are increasing the system pressure. I would start with the fuel distributor and checking what your current system pressure is. You might want to try a search for setting system pressure to get the values and procedure. Fuel distributors are expensive. Read through the above link for some CIS info.

 

http://www.jwsvws.com/CIS%20Troubleshooting.html

http://www.ncr-pca.org/tech/tech-cis.htm

Buy a set of small gauges for cis, and ill run you throgh the steps..... specs,pressures etc,etc..
A shop will take you 3 hours plus to diagnose. I wont charge you a dime.( Maybe a nickel ) HAHA
Porscheworks@aol.com
Jimmy @ Mobile Works

 

Just a thought. that happened to me last summer. In my case, it was a loose fuel pump relay. There is a seperate current path to run the pump when cranking. So, if there is a problem in the primary circuit for the pump, the engine will run as long as you have the key in the 'crank' position, but not when you release it. Of course pinching the return line wouldn't help that, so I'm probably wasting your time.