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rsrmike rsrmike is offline
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Join Date: Jan 2008
Location: Birmingham, AL
Posts: 538
I have seen 930 run rich when the rear pump quits. However, the reason for this is the front pump cannot force enough fuel through the inop. rear pump to maintain proper system pressure.

Considering the warmup regulator, or control pressure regulator, can also be called a differential pressure regulator, meaning it works by maintaining a pressure difference between the upper and lower halves of the fuel distributor. It is also designed to work with a higher system pressure then you get w/ a dead rear pump. I'll stop here at trying to explain the science behind CIS because, well, I can't. I can tell you that when CIS loses fuel pressure, it tends to run rich at times. Unfortunately, the lack of fuel flow can quickly lead to a lean condition w/ increased load which is why 930's are virtually undrivable w/ 1 bad pump and can do all sorts of weird stuff. I hope this makes sense.

Pat, let us know how your fueling issues go, if your using SC CIS, you should be OK w/ 1 pump...
Old 05-23-2008, 03:50 PM
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