'99 v70 AWD Fuel Sender Explanation.

gooproduct · Post by **gooproduct** » 06 Mar 2013, 17:39

So the fuel gauge is not working on my '99 v70 awd. I used Vida to try and find the fault . The gauge needle performs a full sweep when I test it and so I'm assuming the sender is bad.

My question is, I have a sender on the driver side and passenger side. Can someone please help explain the differences and function of the two, and which one or both should I replace?

The needle used to jump around between empty and half then would slowly drop back down. Now it does nothing but stay on empty but does have to travel up a little to reach empty when I start the car. My tripometer and everything else still work fine and the digital messege center relates correctly to the fuel needle, it says anywhere from 40-17 miles till empty.

Donzilla · Post by **Donzilla** » 08 Mar 2013, 15:58

I wonder about the difference too --- physically the level float, the mechanical level reader, and the wiring look identical to me on both sides. Maybe the computer averages the signal? With the tank design, they should stay at the same level all the time IMHO.

Did you have anything done to the fuel pump recently? I've had to re do the fuel pump insertion before when the level float was mechanically blocked. It could easily be the wiring (to either side) as well.

gooproduct · Post by **gooproduct** » 10 Mar 2013, 08:01

No, I have never serviced my fuel pump/level sender units. I have purchased another left side pump/sender and will be performing the "cut the access hole" trick here in the next week. I was hoping to get a little info on the differences between the two left and right side units before I randomly just swap one out.

I purchased a new fuel pump gasket from IDP and in the process I asked them what the function differences are between the two units as they both have floats. The response given to me was only "One is a sending unit pump and the other is a transfer pump." Thanks but it really didn't help that much.

Post by **mikealder** » 10 Mar 2013, 08:12

The tank is more like a sadle tank with two compartments, the sender/ pump is the side that feeds the engine the sender transfer simply pumps fuel from one side of the tank in to the other part.
Both sender units are wired in series so that both levels are taken in to account when working out what the content of the tank is - Mike