New Fuel Pump - losing pressure

[xanth]

yea, another "new fuel pump - issues" thread

I read through alot of threads, and remember seeing some info, but can't seem to find it again.

Basically, installed a Walbro 255 on Sat (Paid someone, didn't do it myself) and also a new sending unit.

Truck ran great yesterday, on way home from work today, started acting like it was out of gas (has 3/4 tank). Got it home, hooked up a fuel press gage, and it looses pressure as RPMs increase. Eventually cutting off the truck. The Pump is running, but it does sound like it's dying as the RPM increase.

I know someone's been there! Before I drop the tank myself (should have just done it, not paid someone!), what's a quick thing to check?

I read alot of new Walbro's had issues, but that was a couple years ago....

If I do have to replace the pump again... what's a good replacement? I was a bit suprised at how loud the walbro was... tolerable, but if i'm going to put in another one, i'd like a quiet one...

Thanks!

 

[Don W.]

Re: New Fuel Pump - losing pressuer

Re: New Fuel Pump - losing pressuer

Replace fuel filter first. Sqeeze the return line and watch the pressure. Ask if the mech if he replaced the surge damper in the tank and if so what kind of hose? Did he replace the sock on the suction side of the pump.

 

[BoostedSUV]

Re: New Fuel Pump - losing pressuer

Re: New Fuel Pump - losing pressuer

Check voltage to the pump and ground for the pump... I would also reccomend using the racetronix hot wire kit. The factory wires are not sufficient to run the extra amperage draw required by Walbro pumps.

 

[hrodgmc]

Re: New Fuel Pump - losing pressuer

Re: New Fuel Pump - losing pressuer

Is it a genuine Walbro? Alot are sold without stamping.


How long does it take to fill a 20 oz coke bottle from the schrader valve? (Measuring volume for a 45-60 psi system)

 

[xanth]

Re: New Fuel Pump - losing pressuer

Re: New Fuel Pump - losing pressuer

Thanks everyone. I'll run the power wires down, check them out, and talk to the mech.

 

[JSM]

Re: New Fuel Pump - losing pressuer

Re: New Fuel Pump - losing pressuer

I would guess either a fake walbro, and/or surge was left on or not fully seated, and you have a leak internal to tank.

 

[TYTILIDIE]

Re: New Fuel Pump - losing pressuer

Re: New Fuel Pump - losing pressuer

If you have a good pump, voltage is well and you end up taking the tank back down, look at the supplied hose that gets installed. Mine went bad in less than two weeks. I had that issue twice. I ended up getting true submersible fuel line. Cost about $20 a foot.

 

[SY2932]

Re: New Fuel Pump - losing pressuer

Re: New Fuel Pump - losing pressuer

If you have a good pump, voltage is well and you end up taking the tank back down, look at the supplied hose that gets installed. Mine went bad in less than two weeks. I had that issue twice. I ended up getting true submersible fuel line. Cost about $20 a foot.

Yep, this is what a "bad" hose looks like:

If the fuel line is your problem be sure to get line that is spec SAE J30R10 or it won't last. It can and be IMMERSED in gasoline. SAE J30R9 which is for inline use, is only meant to have gasoline on the *inside* NOT the outside.

 

[xanth]

Re: New Fuel Pump - losing pressure

So I pulled the pump and checked a few things...

Hooked up a FP guage last night, and the guage was fluctuating 5-10 PSI, constantly, just wasn't holding firm pressure.

Second, the Grey wire on the pump seems to hold a pretty constant 13.2 volts when the pump is priming, however, the purple wire only seems to have ~8v w/ingition on...

Everything looks completely new.

And the pump has a "W" stamped on it.

 

[xanth]

Re: New Fuel Pump - losing pressure

A couple dumb follow up questions for people that have done this before... :lol:

When I put the pump/sending unit back in the tank, I have to push down pretty hard on it, feels like the pump/filter is hitting the bottom of the tank... normal or not? Maybe this is my problem...

Also, that O-ring between the tank and sending unit... is it supposed to fit in that little channel (it's a little big for it...)? Maybe they sent me the wrong O-ring...