I have the filter between the pumps and the sensor. All lines are 1/4" after the pumps (as low as 1/8" through plastic fittings). These pumps definitely creates pulses, even on the input side (the old path was actually tank, valve, sensor, filter, pumps; where the filter would absorb the pulses on the input side of the pumps).

Now, I guess if I had a big filter with air in it (not!) between output of pumps and the sensor, that would absorb the pulses.

Finn

John Downing wrote:

Finn;  Do you have an orfice before the fuel sensor, or is something that doesn't work?  JohnD