Dirty Fuel Pump Rumor

[svrh89]

So I recently heard a rumor from a reliable source but I wanted to confirm it here. I did search for a similar thread and of course there a lot of diagnostic threads on fuel pumps but I didn't really want to read through all that diagnostic info to find my answer. So I apologize if this is overstated or not but I am really curious if it is true because I will be really sad if I have to be hypersensitive to my fuel levels.

I was told recently that the nbs trucks have a fuel pump issue in that if you fly to close to the sun trying to get as close to empty as possible that you will quickly ruin your fuel pump. not an issue but basically I was told to never let my gauge go below a quarter tank or my fuel pump will likely go.

Reason this is an issue for me is I bought my truck for a 50 mile commute to work so 100 miles a day. well the town I live in is about 20 cents or more a gallon and so I much prefer filling up on my way from home but to maintain over a quarter tank I will have days I am forced to fill up at around a half a tank.

Basically I am wondering everyone's opinion on whether or not this is a valid concern or the general population believes this shouldn't be a concern.
I hope not because this for sure limits my effective milage down quite a lot

 

[Tonyrodz]

The fuel pump is cooled by the gas it's pumping. It's not good to let it go under 1/4 tank--imo. If it constantly runs low you run the chance of overheating the pump and sucking up a bunch of junk that's settled on the bottom of the tank. Why take the chance?

 

[swathdiver]

So I recently heard a rumor from a reliable source but I wanted to confirm it here. I did search for a similar thread and of course there a lot of diagnostic threads on fuel pumps but I didn't really want to read through all that diagnostic info to find my answer. So I apologize if this is overstated or not but I am really curious if it is true because I will be really sad if I have to be hypersensitive to my fuel levels.

I was told recently that the nbs trucks have a fuel pump issue in that if you fly to close to the sun trying to get as close to empty as possible that you will quickly ruin your fuel pump. not an issue but basically I was told to never let my gauge go below a quarter tank or my fuel pump will likely go.

Reason this is an issue for me is I bought my truck for a 50 mile commute to work so 100 miles a day. well the town I live in is about 20 cents or more a gallon and so I much prefer filling up on my way from home but to maintain over a quarter tank I will have days I am forced to fill up at around a half a tank.

Basically I am wondering everyone's opinion on whether or not this is a valid concern or the general population believes this shouldn't be a concern.
I hope not because this for sure limits my effective milage down quite a lot

You're not hurting anything if you wait for the light to come on. The pump is surrounded by fuel just about up until the point that the tank becomes empty. Debris in the tank is greater threat to the pump if the sock is damaged.

My kids' cars have 14 and 26 gallon fuel tanks and they routinely refuel them to capacity, meaning they run them to near empty. My tank is over 31 gallons, the light comes around after 25-26 gallons have been consumed, don't think I've ever filled it much over 28 gallons.

See the white plastic in this example photo of the pump assembly? That is the tub that surrounds the pump with fuel. Even after the tank drops below the top of the tub, it will still be full of fuel until near the end.



I don't know about your 800, the 2008+ 900s we can check the health of our pumps by watching its trims. Mine has been steadily creeping up and sometimes down over the years, it's in the 1.5s now. It used to hold running pressure without dropping at all, now it drops 1 psi or 2 at idle and WOT unlike when I first got it.

At some point an executive decision will have to be made to replace it before it fails!

I haven't had to change a fuel pump since the early 1990s in my '80s vintage cars.

 

[Fless]

You're not hurting anything if you wait for the light to come on. The pump is surrounded by fuel just about up until the point that the tank becomes empty. Debris in the tank is greater threat to the pump if the sock is damaged.

My kids' cars have 14 and 26 gallon fuel tanks and they routinely refuel them to capacity, meaning they run them to near empty. My tank is over 31 gallons, the light comes around after 25-26 gallons have been consumed, don't think I've ever filled it much over 28 gallons.

See the white plastic in this example photo of the pump assembly? That is the tub that surrounds the pump with fuel. Even after the tank drops below the top of the tub, it will still be full of fuel until near the end.

View attachment 372294

I don't know about your 800, the 2008+ 900s we can check the health of our pumps by watching its trims. Mine has been steadily creeping up and sometimes down over the years, it's in the 1.5s now. It used to hold running pressure without dropping at all, now it drops 1 psi or 2 at idle and WOT unlike when I first got it.

At some point an executive decision will have to be made to replace it before it fails!

I haven't had to change a fuel pump since the early 1990s in my '80s vintage cars.

^^^ Troof.

 

[RaiderRodney]

The fuel pump is cooled by the gas it's pumping. It's not good to let it go under 1/4 tank--imo. If it constantly runs low you run the chance of overheating the pump and sucking up a bunch of junk that's settled on the bottom of the tank. Why take the chance?

Agreed. I've also heard this for years from both long-time owners and mechanics locally. I try to keep this habit with all my vehicles but definitely with the Hoe.

 

[svrh89]

The fuel pump is cooled by the gas it's pumping. It's not good to let it go under 1/4 tank--imo. If it constantly runs low you run the chance of overheating the pump and sucking up a bunch of junk that's settled on the bottom of the tank. Why take the chance?

This was more or less what I was told. My dad was still turning wrenches when the nbs was still new and he made it sound as if he has seem this happen with customer cars often enough to be a concern.

I have never personally pulled a Chevy fuel pump though so I wasn't sure if there was a design flaw or something.

Thanks everyone for the great info; I will be taking the stance of trying to snot let my tank get to low but won't be hyper sensitive about it

 

[rockola1971]

K and C chassis fuel tanks have a sump area that the fuel pump module sits down in. If you have a 20+ gal tank then you are going to have roughly 5 gals+ of fuel in the tank at 1/4 tank which is more than enough to cover the fuel pump sump area. That sump area might hold 2 gals if its lucky so there is plenty of fuel sitting above that area. As far as dirt or sediment, well that is the fuel pump sock filter's responsibility. No matter what the level in the tank all sediment and dirt is being drawn down toward fuel pump as it is sucking fuel out of the sump area. That fuel pump sock (filter) has to then do its job and prevent that crap from getting into the fuel pump.