gathermewool
Site Donor 2023
97 Subaru Legacy (AWD) with 203k miles.
I've been lazily trouble shooting a fuel pump noise for a while now with very little results. It all started out as a rattle that sounded very similar to a loose heat shield. I'll skip through all of the things that it wasn't, since the below seems to rule out most things. Enjoy : )
In a well ventilated shop, I slowly lifted the pump assembly with the motor running (and the fuel pump plugged in.) The vibration/rattling was still present, so the thought that the fuel pump bracket might be vibrating against the inside of the tank can be ruled out.
With the pump assembly detached from any structure - held in my hands alone - I assume the issue is with the pump itself. I completely removed the whole pump assembly and, after cleaning away all of the flammable fuel from the pump and letting it sit to dry, I very quickly bench tested the pump by applying 12V directly to the contacts for a brief moment. The pump whirred to live and sounded completly normal; however, the pump was only energized for a VERY brief time, so it may not have spun up to full speed. I wasn't gutsy enough to run the pump dry for any extended period - I was hoping for something gross and obvious right away.
Btw, I've had an in-drive idle vibration - not necessarily rough-running, per se' - since changing out both CV shafts. I replaced one of the shafts again; no change. The fuel filter is also new; no change. I'd really rather not have to change out the other other CV shaft, but I may just to rule it out. I know vibration while not moving from a CV shaft seems odd, but it has been explained as the cause of vibration by some Subie owners. May not be relevant, but I figured I'd throw it in there.
Any ideas??? I supposed I should buy a gauge and simply test the system pressure, but I wanted to know what you all thought abuot fuel pump sounds, and if any foreshadowed a not-so-distant death.
I've been lazily trouble shooting a fuel pump noise for a while now with very little results. It all started out as a rattle that sounded very similar to a loose heat shield. I'll skip through all of the things that it wasn't, since the below seems to rule out most things. Enjoy : )
In a well ventilated shop, I slowly lifted the pump assembly with the motor running (and the fuel pump plugged in.) The vibration/rattling was still present, so the thought that the fuel pump bracket might be vibrating against the inside of the tank can be ruled out.
With the pump assembly detached from any structure - held in my hands alone - I assume the issue is with the pump itself. I completely removed the whole pump assembly and, after cleaning away all of the flammable fuel from the pump and letting it sit to dry, I very quickly bench tested the pump by applying 12V directly to the contacts for a brief moment. The pump whirred to live and sounded completly normal; however, the pump was only energized for a VERY brief time, so it may not have spun up to full speed. I wasn't gutsy enough to run the pump dry for any extended period - I was hoping for something gross and obvious right away.
Btw, I've had an in-drive idle vibration - not necessarily rough-running, per se' - since changing out both CV shafts. I replaced one of the shafts again; no change. The fuel filter is also new; no change. I'd really rather not have to change out the other other CV shaft, but I may just to rule it out. I know vibration while not moving from a CV shaft seems odd, but it has been explained as the cause of vibration by some Subie owners. May not be relevant, but I figured I'd throw it in there.
Any ideas??? I supposed I should buy a gauge and simply test the system pressure, but I wanted to know what you all thought abuot fuel pump sounds, and if any foreshadowed a not-so-distant death.