I give up on CIS, need shop advice in Houston

David · David's Garage

I've been trying for months to get a '78 SC to run that's been parked for 5 years. I've cleaned out the fuel system and the fuel distributor piston. I've replaced the fuel filter and dead fuel pump. Now it starts but when I try to rev it, it backfires and dies. The fuel pressure is about 40psi. I've looked for a vacuum leak but I can't find one.

I would appreciate any more advice on what the problem could be, but what I really need is some advice on a good Porsche shop in the Clear Lake area of Houston, TX.

Thanks,
David

SeaDweller · 06-12-2002, 05:38 PM

Have you inspected the airbox?

wckrause · wckrause's Garage

Quote:

pressure is about 40psi

Isn't that quite low for CIS?

makaio · 06-12-2002, 06:51 PM

Quote:

Originally posted by wckrause

Isn't that quite low for CIS?

Very, for a CIS 911.

David · David's Garage

What should the pressure be?

MotoSook · 06-13-2002, 06:29 AM

system pressure should be 65-75 PSIG (with the WUR isolated, motor off, ignition-fuel pump on).

you should see a "warm" pressure (with the WUR in line) that corresponds to the curve for your motor. see Bentley manual or factory manual.

Sunroof · 06-13-2002, 10:01 AM

I got backfiring because my mixture was not set right. I was way too lean so I bought one of those 3mm T-handled allen wrenches
and rather then playing around with a CO meter just experimented til I had it perfect. I did alot of replacing (airbox, cold start valve, WUR, intake runners, etc.) before I finally found this was the simplest solution. "Left lean - Right Rich".

Good luck

Bob
73.5 T (home of the first CIS)