luvmy88

Truck was running good, but after just a few miles my new frame rail fuel pump started getting noisy. While sitting at a light it wouldn't be too noisy but as soon as I started putting a load on it, it became louder. Called the Tech Line at Federal Mogul (pump manufacturer), they think I'm loosing voltage to the pump and that's why I keep going thru pumps. Any ideas on where to check for voltage loss, or what the problem may be? Thanks!

klricks

Several possibilities
Wiring to the frame pump and/ or to the tank pump could be bad.
Check the grounds for tank pump and frame pump.

What did you do with the tank select dash switch after removing the rear tank? That switch if still present needs to always turned to the front tank position. If you have removed the switch then you need to add 2 jumper splices. One for the tank pump and another one for the sender/ gauge circuit.

Check for fuel line damage or kinks.

You can check the flow from tank pump by disconnecting the fuel line at the reservoir and running that line into a container. Jumper the fuel pin on the test connector to force the pumps on. See instructions on my link.
The fuel should flow with a pretty good stream with pumps on. I can't remember the spec but you should know if its working or not.

Just call me Sean

iTrader: (1)

Frame pump gets noisy when the tank pump isn't giving it enough fuel.

luvmy88

The dash switch I did take right out of the system by jumpering the wires as you suggested. I put in a new intank pump and pickup, that's flowing fuel, I forced the pumps to run as you suggested by grounding at the test conector, pump runs. The wires that used to go to the rear tank pump (orange and black) I spliced together and grounded to the frame. Checked my battery voltage not running was 11.5V and running was 14.6V. Had the bed off the truck to do all the work, the fuel lines all looked in good shape no kinks or bends, the frame pump and filter only have just a couple miles on them and the pump is making noise, it;s driving me crazy. My son is coming over to help me get to the bottom of this, I'll keep you posted to any findings, Thanks agagin for your help!

klricks

Did you actually remove the fuel line from the reservoir and run the tank pump into a container?

Did you check the fuel return line? That's the smaller diameter (5/16") line that runs from the fuel pressure regulator and dumps excess fuel back into the tank.
Not for sure but if that line were plugged it may cause what you are seeing?

luvmy88

I had the bed off the truck, I put a bottle on the outlet tube coming from the in tank pump and turned the key on, it was putting a pretty good stream of fuel out. I blew all the fuel lines out with compressed air while they were disconnected from the fuel pump reservoir before I installed the new (single tank) reservoir. I did just put in a new battery this past weekend, the old one would not take a charge, but I haven't started it since. Federal Mogul was thinking I was having a voltage issue. My Son came over this past weekend to "get to the bottom of this" but with the grand kids along we didnt even get to check any voltages. Hopefully he'll be coming over tomorrow so we can check it out. Not only this problem, but I just put two new Flowmasters on it and one of them has a rattling noise coming from inside, probably one of the baffles wasn't propaerly welded in.

luvmy88

Well just took it out for a test drive, pump was nice and quiet for several miles, stopped to get some gas, within a few blocks from the gas station the pump started getting noisy again.

Just call me Sean

iTrader: (1)

The frame one or the tank one was noisy?

luvmy88

Frame one only.

Just call me Sean

iTrader: (1)

Tank problem, the tank pump isn't giving the reservoir enough fuel.