03 Truck Running out of fuel

[jelag]

My neighbors 03 has been changed from the lift pump to the intank pump... .



He drives down the road and runs out of fuel, the gauge shows 1/4 tank and the low fuel light has not come on...



When he fills the tank it only takes 28-29 gallons...



He thinks that the switch on the side of the pump that's connected to the fuel level circuit goes open, (infinite resistance) and signals the computer which shuts down the pump... I've personally not heard of a circuit that turns the pump off when its out of fuel, can someone either confirm or deny this...



I think that the screen in the bottom of the pump (in plastic tub) has been plugged up, so when the fuel stops running into the tub (over the edge) the truck runs out of fuel... . and to me, that is about what's left in the tank...



Any thoughts... .

 

[rbattelle]

He thinks that the switch on the side of the pump that's connected to the fuel level circuit goes open, (infinite resistance) and signals the computer which shuts down the pump... I've personally not heard of a circuit that turns the pump off when its out of fuel, can someone either confirm or deny this...

Like you, I've never heard of such a thing. An easy check, though. Splice a switch into the wires for the pump and the next time it happens turn the pump on manually.



I checked the wiring diagram, and the ECM does get a signal from the fuel tank level sensor, so it's theoretically possible what your neighbor says. But I find it unlikely. The service manual says nothing of the sort in the fuel level sensor description.



Ryan

 

[TCDiesel]

Its time delayed (With engine off) Not running or ignition off, the pump is hard wired, it has no MUX or PCI. 03/04.

 

[Missouri Mule]

What size fuel tank (short bed or long bed)?

Are they still using the infamous fuel sending unit used in the 1rst gen and 2nd gen trucks. Sounds like his fuel sending unit is acting up.

 

[jelag]

It's a short box... I think that the fuel level gauge is right, and the screen on the bottom of the plastic tub is plugged so the only fuel it gets is what runs over the top of the bowl... thus the gauge still reads fuel... and when he puts fuel in the truck it doesn't take 32-33 gal just the 27-28 he says he can put in it... .

Thanks for the input...

 

[rbattelle]

and when he puts fuel in the truck it doesn't take 32-33 gal just the 27-28 he says he can put in it... .

Good grief, I've never been able to squeeze more than 25 gallons into my tank, and that was running it until the gauge read "E" and the DTE was well below 100 miles. Normally I refuel with ~1/4 tank remaining and I can only get 22-23 gallons in it.



Ryan

 

[Missouri Mule]

Thanks rbattelle I thought the 3rd generations would have the same set up as the 2nd generations. Short bed,s have a smaller fuel tank (24 to 26 gallons if I recall correctly) Long bed's have 35 gallon tanks.

 

[rbattelle]

Thanks rbattelle I thought the 3rd generations would have the same set up as the 2nd generations. Short bed,s have a smaller fuel tank (24 to 26 gallons if I recall correctly) Long bed's have 35 gallon tanks.

No, the rated fuel tank capacity for the short beds is 34 gallons. I've just never been able to pump more than 22-23 gallons (on average).



Ryan

 

[3grumpy]

does the intank pump suction go all the way to the bottom? If the pump was incorrectly installed too far off the bottom of the tank, he would run out of fuel. right?

just a guess

 

[MMeier]

No, the rated fuel tank capacity for the short beds is 34 gallons. I've just never been able to pump more than 22-23 gallons (on average).



Ryan

Where does it say that?? Up till the Mega cabs came out short boxes only had 26 gallon tanks as far as I know.

 

[jelag]

The pump is on a spring loaded set of rods... . I assume that the spring loading is allow the pump to fit different tanks... all different heights..... so the spring loading forces the bottom of the pump assembly onto the bottom of the tank... . it sits off the bottom with 1/8" - 3/16" feet... .

Dick (truck owner) has installed a custom vent kit, and with this kit the tank vents well and always fills to the top... . or so I'm told... . When the truck had the engine mounted pump... . he was always able to run the tank down until the low fuel light came on... . now the truck runs out of fuel with about a 1/4 on the gauge... the low fuel light doesn't come on... .

What we're trying to do is figure out what are the options so we only have to pull this tank one time... . Also, please forgive me if I've miss stated the amount of fuel... I was trying to recall from memory based what he said happened before the pump was moved from the engine to the tank...

Personally I can't think of another option other than the screen on the bottom of the pump assemble is plugged and the only way the fuel gets into the pump is over the edge of the bowl that the pump sits in... . in my mind that covers the fact that the gauge is still showing 1/4 tank when its out of fuel, the low fuel light never comes on... . and the limited fuel he can add, as compared to before the pump was changed...

Of course 1 option is to put several holes in the side of the plastic bowl and see what happens... . but we'd really like more input to check out more items before we put this tank back in.....

 

[GaryOwen]

There are good pics and info at the Glacier Diesel Power website. It is in the "Tech Articles" section.

 

[Missouri Mule]

The "low fuel" warning light is activated by the fuel guage on the dash not the fuel sending unit.

 

[Pawpaw]

Where does it say that?? Up till the Mega cabs came out short boxes only had 26 gallon tanks as far as I know.

All of the 3rd Gen short boxes came with 34 gallon tanks.



Bob

 

[TCDiesel]

The pump is on a spring loaded set of rods... . I assume that the spring loading is allow the pump to fit different tanks... all different heights..... so the spring loading forces the bottom of the pump assembly onto the bottom of the tank... . it sits off the bottom with 1/8" - 3/16" feet... .



Dick (truck owner) has installed a custom vent kit, and with this kit the tank vents well and always fills to the top... . or so I'm told... . When the truck had the engine mounted pump... . he was always able to run the tank down until the low fuel light came on... . now the truck runs out of fuel with about a 1/4 on the gauge... the low fuel light doesn't come on... .



What we're trying to do is figure out what are the options so we only have to pull this tank one time... . Also, please forgive me if I've miss stated the amount of fuel... I was trying to recall from memory based what he said happened before the pump was moved from the engine to the tank...



Personally I can't think of another option other than the screen on the bottom of the pump assemble is plugged and the only way the fuel gets into the pump is over the edge of the bowl that the pump sits in... . in my mind that covers the fact that the gauge is still showing 1/4 tank when its out of fuel, the low fuel light never comes on... . and the limited fuel he can add, as compared to before the pump was changed...



Of course 1 option is to put several holes in the side of the plastic bowl and see what happens... . but we'd really like more input to check out more items before we put this tank back in.....

. The module is stuck about 2/3" from the Bottom , remove Tank and see what is causing it to bind... Now I am not a fan of the in tank Pump, around here that screen gets gelled up when -17 or colder (MN has mandatory Bio-diesel). I just can't figure why anyone would want the in tank when its so easy to change the mounted Pump, heck we have had many remove the in tank module and replace with the 03/04 module and mod to the single or dual mounted Pumps. Think of it this way, the in tank fails it’s a tow charge plus remove and install. The side mounted you can change on the side of the road . parking lot, etc in 1/2 1 hour or less at $180. 00 for the pump, it will cost the owner 3 times that for the in tank plus the down time. rarely does the side (factory Pump) mount fail in extreme cold.

 

[Missouri Mule]

Correction on " low fuel warning lamp" there is a cicuit attached to the back of the instrument cluster that monitors the signal from the fuel level sending unit (fuel sending unit). Looked it up in the service manual.

 

[PBJ2500CTD]

Where does it say that?? Up till the Mega cabs came out short boxes only had 26 gallon tanks as far as I know.

I believe tha the gas motored rams had the smaller tanks on the short bed trucks with an option for the 34 gallon. My 98. 5 and 02 short bed CTD both had/have the 34 gallon tank. The long beds a gallon or so more. My 97 gas had the puny tank and I had to stop at every other gas station when towing the travel trailer.

 

[PBJ2500CTD]

I believe tha the gas motored rams had the smaller tanks on the short bed trucks with an option for the 34 gallon. My 98. 5 and 02 short bed CTD both had/have the 34 gallon tank. The long beds a gallon or so more. My 97 gas had the puny tank and I had to stop at every other gas station when towing the travel trailer.

Correction... No option on the SWB gassers - 26 gallon for the 119" & 139" wheel based trucks.

 

[Turbo_Bob]

No, the rated fuel tank capacity for the short beds is 34 gallons. I've just never been able to pump more than 22-23 gallons (on average). Ryan

You must not ever let the level get low enough before fillup.



Before I installed the fuel tank vent mod on my 34 gallon tank, I pumped in 34gallons before. After installing the vent mod I pumped in 38 gallons, I know I was on fumes, but had a 5 gallon can in the ready just in case of any surging. And yes the diesel was up to the cap when I got the 38 gallons in there.

 

[MMeier]

I believe tha the gas motored rams had the smaller tanks on the short bed trucks with an option for the 34 gallon. My 98. 5 and 02 short bed CTD both had/have the 34 gallon tank. The long beds a gallon or so more. My 97 gas had the puny tank and I had to stop at every other gas station when towing the travel trailer.

Please note you are in the 3rd gen forum.