Two Fuel Pumps

lummert · Post by **lummert** » 16 Jan 2012, 09:22

My 1988 Volvo 760 Turbo wagon has an in-tank fuel pump that evidently is not functioning. It is probably what has caused my car to stall on hot summer days with temperatures of more than 90*F. After reading about installing different brands of fuel pumps I read that having two fuel pumps is redundant. Would it be reasonable to remove the in-tank pump and replace it with a length of steel gas line and just use an inline pump. I have read about using a high pressure pump as an in-tank pump and deleting the inline pump, but that seems to be more work with the fuel lines.

Post by **writer100** » 16 Jan 2012, 20:16

I wouldn't try it. Why not just replace the tank pump?

Post by **jimmy57** » 16 Jan 2012, 22:15

Not all fuel pumps are equal. Your car has a high volume, low pressure pump inside the tank. The high pressure pump is beneath the car with the fuel filter next to it. If you do anything it would have to be to saw, whittle, clamp, and file your way to having the later two in one fuel pump inside the tank. Volvo started using a single two stage pump with the low pressure stage and the high pressure stage in one pump in 90 on some 740's. The 850 models premiered with this system and the 900's got it in 1995.
The earlier cars have a very long life main pump under car with the pre-pump inside the tank pushing fuel to the main pump so as to prevent vapor forming in the line from tank to main pump. You could fit the two stage pump but it costs more than the single stage your car has down in the tank.