lowfly
FASS Technician
Here are some very basic guidelines for diagnosing the FASS and HPFP systems
5 GALLON BUCKET TEST
1. Remove the suction side fuel line from the tank.
2. Remove the return side fuel line from the filler neck
3. Insert both of these fuel lines into a 5 gallon bucket half filled with diesel fuel.
4. Put the key to the run position (DO NOT START THE ENGINE)
5. Read PSI readings while pump is running.
From this test you should be able to determine what PSI your pump is running. If you are having low or no PSI issue with your truck than this is the first thing you should do. It isolates the pump from the rest of the truck and lets you know if there is any restriction that the pump is having to draw through,
Verify the accuracy of your gauge. If your using any tuner/programmer to check PSI verify that PSI reading with a good mechanical gauge ported directly to the pump.
Check all fuses in system. We have a 30 amp fuse inline with our wiring harness but there are other fuses and relays that would cause electrical issue with the pump.
Be thorough in your diagnostics. the issue that you missed is usually the one causing the issue.
When all of this fails then you will need to contact your local FASS dealer and we can work out warranty stuff from there.
Good luck and thank you for choosing FASS Fuel Systems
5 GALLON BUCKET TEST
1. Remove the suction side fuel line from the tank.
2. Remove the return side fuel line from the filler neck
3. Insert both of these fuel lines into a 5 gallon bucket half filled with diesel fuel.
4. Put the key to the run position (DO NOT START THE ENGINE)
5. Read PSI readings while pump is running.
From this test you should be able to determine what PSI your pump is running. If you are having low or no PSI issue with your truck than this is the first thing you should do. It isolates the pump from the rest of the truck and lets you know if there is any restriction that the pump is having to draw through,
Verify the accuracy of your gauge. If your using any tuner/programmer to check PSI verify that PSI reading with a good mechanical gauge ported directly to the pump.
Check all fuses in system. We have a 30 amp fuse inline with our wiring harness but there are other fuses and relays that would cause electrical issue with the pump.
Be thorough in your diagnostics. the issue that you missed is usually the one causing the issue.
When all of this fails then you will need to contact your local FASS dealer and we can work out warranty stuff from there.
Good luck and thank you for choosing FASS Fuel Systems