Car fires then dies - won't run. Fuel pump ?

[EarlySport]

Hey guys.

Hoping for some help. My 911SC sat for over five years not running. After all the usual ( pulled plugs, cranked engine manually, then cranked on starter to get oil pressure ) I tried firing it and had nothing. Found the fuel pump had died, so I bought a Bosch EFI pump and fitted it. This was not a factory CIS pump, but a generic bosch.

I then fired the engine, and it ran real rough. I kept pulling plugs and cleaning them, putting them back in, and eventually got it running on 5 cylinders, and called it a night.

Last night I fitted all new plugs, expecting it to run. I fired it but then it dies within a second or two of starting. When it ran for that second or two it sounded clean. My thought is I now have a fuel problem - I'm stumped though as to why it ran the other night and now it won't ! My suspicion is that the fuel filter may be blocked now with old gunk from the tank, so this would be my next change. I made sure the tank had fuel in it too, before anyone suggests that.

I have some questions though - Do you think the generic EFI pump can supply the pressure the CIS system needs ? Its a Bosch pump with the same fittings that is rated at 400hp, but this would be at 40 odd PSI, not the 75 or something I vaguely recall CIS runs at.

Also any other thoughts as to what might be wrong would be appreciated, or diagnostics for me to try.

Thanks all !

[asphaltgambler]

You did not mention if you had drained the fuel tank, flushed the lines, replaced the fuel filter. ALL things to do even if the car sat around unused for 8-9 months. Gasoline at rest will start to seperate after only a few months.

I would start there first

[Huh]

I don't know about the Porsche but I had a Scirocco sit for 2.5yrs. I didn't clean out fuel tank just tried running it. It has CIS and it started right up and that was before putting in some sea foam. The car now runs like a champ and nothing done other than fuel filter. You should have your fuel pressure tested. The fuel pump must put out around 75psi. Your fuel pump may not be suited for CIS motors.

[EarlySport]

I think the fuel filter is my next course of action, followed by a pressure test.

I did store the tank empty in the time the car was sitting idle, so I started with an empty system and fresh fuel.

It was just the whole ' start and run for 2 seconds ' scenario that I thought may have rung a bell with some forum members.

Craig H

[john walker's workshop]

an EFI pump will not run a CIS system.

[dimps8]

Welcome to the board Early. If you only ever take one persons advice, make it JW's above.

[NevenM]

but this would be at 40 odd PSI, not the 75 or something

Well you nailed it there, in all FI systems pressure is critical and I think you are pushing the proverbial up hill to get this to work, You will have to obtain a working CIS Fuel pump

HTH

Neven

[Huh]

Yes it needs the pressure to open the mechanical injectors properly to get good atomization.