Fuel Pump question

[Ski]

Ok ya'll, this is the question I have. What exactly does the sending unit do for the fuel pump. As most of you know I have had a problem with my fuel flow that seemed to be a guage problem, it wouldnt start, I would put a few gals of fuel in and it would start, last about 2 weeks then ****, wouldnt start again, add gas and it would start. This has been the cycle for the past couple months now. Well now today I put in 20 bucks and the tank is full. The guage reads full and it is full. So the guage is not incorrect. Could it be the sending unit?

 

[Justshootme84]

The sending unit itself just measures resistance as it rises or falls with the fuel level. On your 96, it's part of the fuel pump assembly anyway so changing it means changing the whole ball of wax. JSM84

 

[Ski]

The sending unit itself just measures resistance as it rises or falls with the fuel level. On your 96, it's part of the fuel pump assembly anyway so changing it means changing the whole ball of wax. JSM84

So would you say that it is possible that the sending unit is bad, causing the pump to not actually send fuel? Even with the pump running? I do not want to waste money on a new pump if it is not the problem.

 

[crazyhorse85]

I'D SAY SAY EITHER YOUR PUMP IS GOING BAD OR THE SCREEN ON THE PUMP MAY HAVE SOME TRASH ON IT...MY SON'S 92 EXPLORER WAS DOING PRETTY CLOSE TO THE SAME PROBLEM,HE CHANGED THE FILTER THEN WNT TO CHECKING THE GAUGE THOUGHT IT WAS READING WRONG....ALL IT WAS THE PUMP PRESSURE HAD DROPPED BELOW 40LBS....CHANGED THE PUMP AND ALL IS WELL AGAIN....

 

[Ski]

I'D SAY SAY EITHER YOUR PUMP IS GOING BAD OR THE SCREEN ON THE PUMP MAY HAVE SOME TRASH ON IT...MY SON'S 92 EXPLORER WAS DOING PRETTY CLOSE TO THE SAME PROBLEM,HE CHANGED THE FILTER THEN WNT TO CHECKING THE GAUGE THOUGHT IT WAS READING WRONG....ALL IT WAS THE PUMP PRESSURE HAD DROPPED BELOW 40LBS....CHANGED THE PUMP AND ALL IS WELL AGAIN....

Well I am guessing then the only way to really find out would be to pull the pump. Which of course now I have a full 33 gal of fuel in my tank, good luck getting that down without spilling it!

 

[Justshootme84]

So would you say that it is possible that the sending unit is bad, causing the pump to not actually send fuel? Even with the pump running? I do not want to waste money on a new pump if it is not the problem.

No. the fuel pump can still work, even if the sending unit isn't working. Often, the float on the end of the sending unit will deteriorate and break off, leading to wrong readings on the dash gauge. A more common problem, like CH85 stated, is that the pump is going out due to a hole in the pick-up screen allowing trash to corrupt the pump. Before dropping the tank and spending $250 on a new sending unit/fuel pump assembly, you can check the fuel pressure. Consult a HAynes or Chilton manual for that procedure. JSM84