Working on My Grandpa's truck... He told me we wants me to put in a new fuel guage in... His truck keeps running out of fuel with the guage still reading anywhere from 1/4- 3/8 tank left... Is this a sign of a bad lift pump or is something else I should check... Mayne a bad sending unit in the tank?? I've been trying to talk him into the low pressure Led light for along time, but he has been stubborn..

The truck is a 2002 with 80k on the ticker...

 

It could be either , level sending unit or an issue with fuel delivery [ pickup - pump ] .
Being an 02 , not sure if it has the VP or C3 , if VP that's bad , as I understand , the VP can start & run the engine with the LP dieing , making the VP work harder , shortening its life .
To find out witch of the 2 possibilities , you may need to pull the tank or lift the bed & look at the 2 units to see if it the sender or the pickup .

 

I recently went through this on my '99. Truck ran out of fuel with the gauge reading 1/4 tank full. I replaced the sending unit and all is well. Have you determined that the tank is actually empty on your grandpa's truck when it comes to a halt? In any case, definitely install a fuel pressure gauge in the cab.

 

IT has the Vp44 Sounds like the sending unit would be bad to me... But not sure.. I've heard of a lot of lift pump failures, but not the sending units..

 

Yup... I just got a call and my uncle put in 6 gallons out of a can, got it running again.. then went to the gas station and put in another 29... So she was good and empty..

 

Over 30 + yrs in repair , I have put many sending units in , all kinds of trucks & cars .
So with those numbers on filling , that should make it the sending unit , not rending correctly , ask if he rides around with the tank on the lower side more often that on the higher side , I would say lower , what goes bad is that the sender has an arm that rubs on windings of coil , the arm tend to wear through the spot that it sits on the most .

 

Cool, thanks... Na, gramps is the kind that fills er up every time it gets low... The truck is maninly used on trips, hauling a 15k fithwheel around.. Once he gets done with it moving some machinry around I'll drop the tank next week and fix it for him... Thanks for the tips guys

 

Prolly is the sending unit, but also could be a huge upset in the floor of the tank from a large curb or rock or berm

 

I've had the 1/4 tank problem well before replacing my LP. Sounds like a sending unit to me too. Shuts off the LP/IP. PITA. Made my LP die too (theoretically). Good luck.