Glenn, your fuel transfer pump is a mechanical pump that is powered off engine HEUI
Pump. I have a suggestion before you spend a lot of time, to check the Racor fuel/water
Filter on the discharge side for exit of air ( this can be done by using about 10 inches of
Clear plastic hose that can be found in the hardware dept.) connect discharge side of water/
fuel filter than to suction fuel line going to fuel transfer pump. Start engine and see if there
Is a clear stream of diesel fuel with no air showing inside plastic hose. Note: any air present
you have a problem. Second step remove fuel line to suction side of fuel/water filter and
connect clear line to fuel line coming from fuel tank, again if any air bubbles present. If
Not your problem is now located to the Racor water/fuel filter. Gerald explained the Racor
setup will need attention. Dave Atherton Retired Cat Mechanic