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rsrmike rsrmike is offline
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Join Date: Jan 2008
Location: Birmingham, AL
Posts: 538
lol you sound like me when you say suuxxxxxx. Fuel pressure sounds funky. I'm thinking you may have a delivery problem vs a regulator problem right off hand. It's hard to say w/o actually seeing what it's doing. I'm not sure which FPR you have or what it's pressure should be. If it is a stock 3.2 carrera, that static reading may not be too far off. I can't remember. I would look into the pumps first though. If you have 2, one near the steering rack and one in front of the LR tire, then they are likely CIS 930 pumps. If so, first make sure they both run. If one dies on a cis 930 it will hardly run. In your case it may not be as dramatic as EFI doesn't require nearly as much volume. CIS is using a portion of the volume from the pumps to control the fuel mixture. It also operates at a much higher pressure. that also brings up another point, I've heard that concerning 930 CIS pumps, one is designed for more volume while the other is designed to raise the pressure. Usually, when one pump dies, the other gets very noisy as it strains to either push or pull fuel through a dead pump (dependent upon which one quit) Obviously, if it's one pump trouble it could be one of the relays or a wiring problem.(anything is possible on these old beasts) If both pumps run, but are noisy, I would look at the fuel filter(duh), but also check the supply to the first pump from the tank. The fuel tanks are neat but can have problems if gunk accumulates in the bottom. It may be easy to do a flow rate test. If you have 930 pumps they should pass a CIS flow test w/ flying colors. (most CIS pumps can double the minimum flow in the alloted time) I think it is 1100 cc in 30 seconds??? Not sure but someone knows or has the books. I can't remember. One thing for certain though, Porsche says to test the flow AFTER the injection system. I guess mainly so that not only will the pumps have to make the flow, they have to it under pressure which makes them work harder. 930 pumps would probably flow 1100 cc in 10-15 seconds at 37 psi... to be continued
Old 05-20-2008, 05:52 PM
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