gwmckinley

Howdy
Just purchased 74 911 targa with 165000 showing, recepts from a major overhaul <20000 miles ago . Drove the car for about a mile and it stalled pulling up to a stop sign and would not restart. Let it cool off and it would restart but ran very rough with lean backfire. Purchased CIS fuel pressure set up and found primary pressure at 55 psi. Replaced fuel pump (making alot of noise), check valve (ball and spring removed by persons unknown) fuel filter(original type) with no improvement. A new fuel distributer brings pressure up to 65psi but now the car will not start. The old fuel distributer was clean as could be when disassembled but I could not get it to seal after seperating the body.The tank seems clean, very low humidity here in New Mexico so tanks dont rust. I have found several discussions on the 74 CIS in the archive but only problems no remedies. I will be gratefull for any advice. I purchased the SOLVING BOSCH CIS Problems Manual but it makes no mention of the control pressure regulator version used in the 74. Can anyone suggest a more relavant manual or are the factory manuals the way to go?
Thank
GW

Brett San Diego

What is your cold control pressure? Is it within spec? What about your injectors? Delivering fuel as they should? How about the cold start injector? Air sensor plate moving OK, adjusted OK? Any idea of mixture adjustment condition? When it was last performed? Any history at all? What about spark? Good to all cylinders? Condition of distributor cap and rotor, spark plugs and wires?

Brett

gwmckinley

Cold control pressure is 55 psi and its 90 degrees outside. Injectors were recently replaced by previous owner and pulling one shows a conical even spray pattern. dont know about the cold start injector or mixture adj condition. sensor palate seems adjusted correctly and moves freely. cap and rotor look fairly new wires are original type but do not seem overly brittle.

gwmckinley

update
one and one half turns on the idle mixture screw has her running, a little rich but now I can drive to someone with a co meter and dial that in. I dont understand the cold pressure seems out of spec but it seem to run very smoothly and purrs at idle so i will ignore that until it effects performance.
Brett thanks for the help.
Slick

Brett San Diego

Good job. The only work I've paid for on my car in two years was a timing and mixture adjustment after I did a valve adjustment myself. Can't do mixture myself without a high quality exhaust gas analyzer. I'm not experienced enough with CIS to tune by sound and feel, and I don't really trust the portable one from Gunson. It was $90 well spent. The car really came to life. It was a bit lean before. Anyway, my point is to advise an immediate valve adjustment and mixture adjustment. Pete Zimmerman recommended that I do the mixture after a valve adjustment, and it was golden advice. My car is a 78 SC.

Good luck with the new car,
Brett