Fuel pump questions

Road_Runna

Dirt-Old 20+Year Member
Dec 23, 2002
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Ogden, UT
I tested fuel pump pressure on the car today (94 GT 5.0) and am getting zero (0) pressure even tho the pump can be heard priming in the back, getting 12 volts at the 20amp fuse under the hood. The fuel shrader valve barely puddles. My rpm needle jumps slightly when i crank the motor, there is clicking at the ccrm, and car has a new fuel filter, no gas can be smelled from regulator. Car will turn over when starter fluid is sprayed into the throttle body inlett. Yes i am getting spark.
My question is would a 255 lph fuel pump be too much on a stockish 5.0.
Only big mod ive done so far is the intake manifold is a edelbrock performer.
Cylinder heads or a Kenne bell are planned out for next year if things stay the same financially.
The culprit is pointing out to be the fuel pump, strainer clogged or hoses. I wont know fully until i unbolt the tank off and look at the strainer and hoses.
I believe ive gone through the checklist posted on these forums.
So would a walbro 255lph overkill for stockish 5.0?
 
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A 255 has been ran on stock setups in the past without issue. Sn95s have a slightly larger fuel return which helps with the excess fuel the 255 will Inevitably pump.
If you plan on upgrading in the future it’s not a bad idea.
 
A 255 has been ran on stock setups in the past without issue. Sn95s have a slightly larger fuel return which helps with the excess fuel the 255 will Inevitably pump.
If you plan on upgrading in the future it’s not a bad idea.

Good to hear.
i really din't think of compatibility issues when i purchased the pump.
Basically i ordered it first thinking the regulator will regulate how much and then drain back to tank, that was my thinking to begin with on my stockist 5.0L.
It should be here Tuesday along with my fuel filler floater. I just got my new tank today.

I do believe i have bad gas in there, seen some jelly looking sludge dripping out of my new fuel filter.
 
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If you disconnect the lines at the Rail and tank you can blow them out with compressed air. That then cycle the key a few times with the rail still disconnected to clean a bit more.
 
Disconnect the fuel lines on the passenger side of the engine, connect rubber hoses to them and direct them into a small bucket or catch pan then blow them out with compressed air. The rest of the fuel lines on the engine can be removed and cleaned. If there is a lot of goo in there then I would get the injectors tested too.
JMO and not based on any real mechanical experience.
 
Finally got her running.
I found the rubber "S" hose with a crack on it, only after ordering all my parts in the mail. New tank, new fuel gauge, walbro 225lph pump and seals.
Installed everything except the new pump, i figured the old one would still be good to use; i was wrong.
2nd time pulling the tank down; i installed the walbro pump, fired right up. Pushing down on the shrader valve, gas goes so high it actually hit under the hood.
Pump isn't quiet at all! Which is what i like, makes thing sound like there's something evil coming up.
 
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I guess that depends on what you're comparing it to - a nice rumbly exhaust for example. The Walbro is definitely a bit buzzier than the stock unit, which is already buzzy when standing outside the car.
I can testify to the walbro being a bit louder than stock. Although i only have about 2 or gallons of fuel in the tank.
My stock pump seals might of been bad, but it was still trying to push fuel thru, just not as much as it should.
Walbro is a atleast 20% louder than stock. On 2 or 3 gallons of fuel.
 
Don't worry, just park next to me when my T-Rex inline is running, I promise you won't hear your in tank Walbro. You might not even hear your exhaust.

Kurt
 
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I can testify to the walbro being a bit louder than stock. Although i only have about 2 or gallons of fuel in the tank.
My stock pump seals might of been bad, but it was still trying to push fuel thru, just not as much as it should.
Walbro is a atleast 20% louder than stock. On 2 or 3 gallons of fuel.
I’ve ran numerous in tank fp sizes and never noticed any being all that loud. Hell even my aeromotive a1000 really isn’t bad at all when the car is running.
 
I’ve ran numerous in tank fp sizes and never noticed any being all that loud. Hell even my aeromotive a1000 really isn’t bad at all when the car is running.

Agreed. The difference in noise between any of the in tank pumps is going to be negligible. Now, my old school in line T-Rex is a whole other story.

Kurt