hey guys...
well heres the low-down. I have a 255 walbro. Works great. Except all the time theres a noise coming from under the car..around the tank where the pump is. Its no an exhaust leak because i have checked and re-tightened down all connections. Now my question... I NEVER fill my tank above 1/2. Call me crazy but I can really feel the difference between a full tank and 1/4-1/2. I read a article in a magazine that if you run with a low/empty tank over and over again it can hurt your fuel pump, and will burn it out. IS THIS TRUE? The only times i have ever put more than 1/2 tank is if I go on a long trip.(which is RARELY) please give me your opinions and feed back!!! Am i burning up my pump or damaging anyhitng??THANKS!

 

The Walbro pump does get louder when your tank is low. I would recommend to have at least 1/4 of a tank so you don't over work the pump.

Thanks,
Tom

 

I never let my tank go below 1/2 tank.. I think that humming is normal.. I've heard from a couple people that the upgraded walbro is alittle louder. As for burning out your fp.. I can't say for sure, but I don't think that would happen.

 

I remember in automotive class the teacher saying driving constantly on low fuel and running out of gas could lead to damage to the fuel pump in the long run.

 

the walbro is a louder fuel pump so thats the noise......as for burning up ur fuel pump this is true.....if u have no gas in ur tank then the pump has no sort of lubrication. they are lubed by the gas. if i were u i would put more then 1/2 tank of gas in...u never know when an emergancy if going to happen where u need more then 1/2 tank of gas. But the huming is normal and u can burn ur fuel pump up. hope this helps

 

They get really loud if you let the tank get low on you. I remember in my GSX my pump sounded like a hairdryer in my back seat. Ive also heard that runing low time after time will ruin a fuel pump.

 

the fuel pump is cooled by the gas too, and always running around with a really low tank will make it more prone to sucking up debris and crap on the bottom of the tank.

 

Yes the fuel cools the pump,low fuel when parked over a cool night promotes condensation.High G's can allow starvation.Evo's have fuel temp sensors also.

 

thanks for all the input

 

the fuel pump sits in a resevoir. The fuel return from the rail flows back into this resevior, fills the resevior first, and that spills back into the main tank. The pump is always in a fuel bath that may be a bit larger than a 1/2 gallon or less. It keeps the pump cool and primed, around turns, on steep driveways etc. Envision one of those glass globes that cover the light bulb in a cheap light fixture, you know the type, you have unscrew three screws to drop the frosted glass to get to the ligth bulb.

Running on a low tank (1/4 tank) won't damage the fuel pump, unless you basically run it out of gas with regularity. I have the Walbro also, but I haven't noticed any noise associated with it.

 

my pump is done and I NEVER go below half a tank so the theory that lower fuel kills the pump is more than likely untrue. Read post above mine as it is true in thats how the pump works.
Honestly I think its just a defect. Sometimes things just break.

*note im talking about my walbro 255 pump

 

btw you arent crazy - the car is noticeably sluggish with a full tank of gas (well, relatively sluggish)

 

Why don't you ever fill your car all the way up? That just doesn't make sense.

 

EXACTLY!!!

As someone mentioned earlier, gas lubricates the fp. if no gas is going through the pump, it is just pumping air and "dries" itself out which in turn doing this enough times or long enough once, will burn the pump out. I know cause i did this on one of my other cars with a walbro fp. i ran it out of gas and it burned out both my fuel pumps within seconds (i had two pumps, one external and one internal)

it should be okay to run your car at a 1/4 or more all the time but i wouldn't recommend it if you are tracking or autoxing the car. the fuel moving around can give you fuel cut if the tank is low. i felt it a couple times when i autoxed my car (evo) on a low tank.

As for the noise, mine whined a lot more when it was below a 1/2 tank. I believe this is due to the fact the pump is not submerged all the way and when it is it just muffles it more. Regardless i always heard mine cause all my interior was removed from the car so any slight change in sound, i noticed very easily.

 

yes dont road race your car with 1/8 fuel or less - you will get fuel cut in the corners....