View single post by Greg Fletcher
 Posted: 08-13-2008 05:17 pm
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Greg Fletcher

Joined: 03-11-2005
Location: Lake Nacimiento, California USA
Posts: 421
The glorious, original SU fuel pump is a wonder of mechanical engineering. It will work fine with any amount of fuel in the tank, other than none. It will pump up to operating pressure every time you start the car since it is not advisable to keep the fuel system pressurized full time. You didn't say if you are using the SU or some other, lowly, after market version. On the SU, there is technically a built in "check valve", but I would guess that a fault would be more likely to be found in the vacuum valve from what you mentioned. The old pumps can be rebuilt to fix any problem.