New pump, Low fuel pressure!

[jim3326]

So I went ahead and put the Deatschwerks pump in thinking I could be ahead of any issues with a 'too loud' pump which is why I was going with the new tank in the first place. Frame mount pump was way louder than what your video was. Got everything hooked up, started pump, checked for leaks then started engine.

Engine runs fine it seems, can't drive it yet need driveshaft. What concerns me is it's only showing 20# on the gauge. My loud frame mount would get as high as 43# and was 40# when I started this adventure.

Any input is appreciated. Thanks, Jim W.

And as I was hooking everything up, this poked me in the eye!

 

[DirtDonk]

Back to the top.
Not sure what could drop the pressure to half of what it was before, without some sort of defect. Either the pump or the tank.
Are you sure there is enough fuel to prime the new pump? I could see it pumping air and doing some bad stuff like that.

As you're thinking, the 40-43 (up to 46-48 sometimes) is the proper pressure. At 20 or so you could have lots of driving issues under load.

What tank and in-tank setup are you using?

Paul

 

[marshall godron]

Looks like it’s time for a heavy duty shackles. I broke a stock one on a wheeling trip. Lots of fun getting it off the trail

 

[Chief Master Sergeant]

I think I have a spare stock shackle sitting in my parts pile, if you want it.

 

[jim3326]

Back to the top.
Not sure what could drop the pressure to half of what it was before, without some sort of defect. Either the pump or the tank.
Are you sure there is enough fuel to prime the new pump? I could see it pumping air and doing some bad stuff like that.

As you're thinking, the 40-43 (up to 46-48 sometimes) is the proper pressure. At 20 or so you could have lots of driving issues under load.

What tank and in-tank setup are you using?

Paul

Hi Paul, I'm using the Sherman I got from you. I replaced the pump with a deatschwerks after reading the other post about the loud Walbro. Probably should have just gone ahead and used it buuuut%) I put about 3-4 gallons in, maybe it wasn't enough to get a fresh pump primed. The dash is flashing 4% fuel.

 

[jim3326]

I think I have a spare stock shackle sitting in my parts pile, if you want it.

Thanks Chuck, It's not so bad that can't weld it up, just part of the 'Bronco rabbit hole'.;D

 

[DirtDonk]

I think 4 gallons should be more than enough to bury a fuel pickup filter and get things going. Maybe not always for the first time I suppose, but I would think it's enough.

My reason for asking though is I'm wondering if you got one of the tanks with the funky weld on the pickup tube that caused some flow issues.
In theory it would have showed up with your old pump as well, but I wonder if there is a difference in "head" (if that's the proper term) that a pusher pump can put out at first fire up, vs what a puller can do? I don't think so, but I don't know either.

Did the tank already have the internals for an in-tank pump? Or did you purchase the kit later? If you can get to it easily enough, maybe push something through the outlet, such as a piece of wire or something, to see if there is any restriction in the tube.

I still doubt this is the issue since the old pump worked fine. I'm just grasping at any straw to figure out why one put out 40 and the other 20.
Bottom line though, is that it can still be the new pump is bad, or your regulator is bad coincidentally.
After all, these pumps actually can put out up to 100psi and the regulator is what necks it down to the usable ranges. Not sure if a regulator can knock it down to 20 like that, but it seems possible.

Good luck.

Paul

 

[DirtDonk]

Oh, and 4 gallons and 4% don't seem to compute either.
Has it always read off at the gauge? Or has it been pretty good?

A low voltage or bad ground issue for both the sending unit and the pump maybe? Low voltage was not something I thought of regarding the low pump pressure until just now.

Something to think about. anyway. Longer wire extension and all that. Maybe you spliced extra wire to the old one? Could the splice have a voltage loss?

Paul

 

[jim3326]

Paul,
The tank was built for the pump. I checked the outlet before I coated the tank but not after. I may have clogged it if that's the problem. The way the sending unit is fitted, it doesn't go to the bottom but rather hits about 2" up the sloped rear part. The gauge reads pretty accurate when you consider the wacky shape of the tank.

The pump I had before was a frame mount Walbro that was constantly screaming at me. I believe it was due to starvation. IIRC the NWP tank pickup tube just rests on the bottom and didn't have a sock on it. When I was draining the tank, the fuel wasn't flowing from the 4070 pump. I back blew the line and it started flowing like it should. I haven't opened the tank yet to check if there is garbage inside.

I'll check on the voltage. As far as the ground, 4 bolts, 1 ground wire. Short of a dedicated wire...….