1978 911 SC won't start

[poy louie]

car will not start when cold, car starts momentarily, then dies. Never any problems starting before

[Gunter]

Could be 99 different reasons.
Stock '78?
Post more info on when the last tune-up was done.
Exact details on components for CIS, CDI, "green" wire, plugs, wires...........
AAR, AAV, Thermo-timer, CSV working?
How old is the pump?
If you don't have one, get the Bentley SC Repair Manual, learn about Bosch CIS and how the components work.

[poy louie]

car is stock with the exception of stainless heat exchangers, last tune up, plugs, wires, dist.cap & rotor, last year, only 1500 miles since. Green wires ?,
CDI injection, Pump?AAR,AAV, Thermo timer,& CSV?

[Two Tone]

Originally posted by poy louie
car is stock with the exception of stainless heat exchangers, last tune up, plugs, wires, dist.cap & rotor, last year, only 1500 miles since. Green wires ?,
CDI injection, Pump?AAR,AAV, Thermo timer,& CSV?

I think Gunther is asking if any of these items is malfunctioning, has been modified or maybe replaced with something else:

Green Wire: I think that is a wire going to the Distributor that is known to fail.
CDI : Capacitoral Discharge Ignition - the silver box on the left wall of the engine bay.
CIS : Bosch K-jetronic Continuous Injection System. This is the fuel injection system on your car if stock.
Pump: Fuel pump - is it working? (Its electric and up front under the gas tank)
AAR: Auxiliary Air Regulator - part of the CIS
AAV: Auxiliary Air Valve - part of the CIS
Thermo Time Switch - part of the CIS - assists cold starts by activating the CSV: Cold Start Valve.
WUR - Warm Up Regulator - part of, wait for it.........., yes! the CIS!

You need to search on each of those terms.
Also, read this thread: It's that time of the year AGAIN! (CIS)

Look at the links in the signature of the guy who started that thread, Souk. All very helpful info.

And finally, post back when the problem is solved so others may benefit.

Good luck.

[ossiblue]

If you have a pop-off valve in the air box, check to see if it is leaking or stuck open. What you describe is a classic symptom--just one more of the possible 99 possibilities.

[favrok01]

did it backfire on you at all?
do you have a pop off valve?
is the air bean cracked or loose?
when you take the air filter off with the car on push the plunger up do you hear a whine?
are the the 2 wires on the bottom left of you cam cover connected well? (that is the Thermo Time Switch )
it is in a close loop circut with your cold start valve which sprays fuel into all the intakes.
are the contacts to the fuel pump fuse oxidized?

etc..

etc..

i hate that i actually have learned all this crap.