Fuel Pump Questions

[foss40z]

I took a trip last week down to Tucson for work, and drove down 140 miles and truck ran fine but i did notice a little bit of power loss going up small hills. I did my job then went to gas station and filled the tank and took 9 gallons of gas. I started on my way back home and 40 miles later while on the freeway the truck started to sputter and start to die until i gave it more gas. It did this for about 5 more miles so i pulled off the freeway and the truck died. I tried to fire her up and nothing.

A guy pulled off to help and we started going threw things. We unplugged the MAF sensor and it fired right up. So I continued trying to make it home, with engine lite on and it not locking up in OD, and in 5-7 miles later it started sputtering and dieing again. I tried to make it to the next exit and she just died and did not start back up so i had to get a tow back home. I was noticing a slight whine from the rear of truck and was not sure if it was the fuel pump or the rear end.

The truck did use more gas then normal going down to this location because last i drove down there i only used 6 gallons and now i used 9 gallons. Would this be a in tank fuel pump or the high pressure mounted on the chassis? I will check the fuel pump on the chassis in a bit. IF the in tank pump goes out will the high pressure pump have enough pumping pressure to suck the gas out of tank threw bad in tank pump or no??

Also what else would cause the truck to suddenly sputter and die? I changed fuel filter the day before and a few other things, so there is no restrictions in the fuel line. I did pull off the fuel line from the in part of the new filter on the chassis and fuel was leaking out like crazy from the high pressure pump side and would not stop, with the truck off. perhaps the high pressure pump seized up in an open position and is allowing to leak? Any thoughts i would greatly appreciate.

Mr.Foss

 

[IMenriched]

I took a trip last week down to Tucson for work, and drove down 140 miles and truck ran fine but i did notice a little bit of power loss going up small hills. I did my job then went to gas station and filled the tank and took 9 gallons of gas. I started on my way back home and 40 miles later while on the freeway the truck started to sputter and start to die until i gave it more gas. It did this for about 5 more miles so i pulled off the freeway and the truck died. I tried to fire her up and nothing.

A guy pulled off to help and we started going threw things. We unplugged the MAF sensor and it fired right up. So I continued trying to make it home, with engine lite on and it not locking up in OD, and in 5-7 miles later it started sputtering and dieing again. I tried to make it to the next exit and she just died and did not start back up so i had to get a tow back home. I was noticing a slight whine from the rear of truck and was not sure if it was the fuel pump or the rear end.

The truck did use more gas then normal going down to this location because last i drove down there i only used 6 gallons and now i used 9 gallons. Would this be a in tank fuel pump or the high pressure mounted on the chassis? I will check the fuel pump on the chassis in a bit. IF the in tank pump goes out will the high pressure pump have enough pumping pressure to suck the gas out of tank threw bad in tank pump or no??

Also what else would cause the truck to suddenly sputter and die? I changed fuel filter the day before and a few other things, so there is no restrictions in the fuel line. I did pull off the fuel line from the in part of the new filter on the chassis and fuel was leaking out like crazy from the high pressure pump side and would not stop, with the truck off. perhaps the high pressure pump seized up in an open position and is allowing to leak? Any thoughts i would greatly appreciate.

Mr.Foss

Mr. Foss

getting that much of a decline in MPG's is pretty significant, do you normally get 23mpgs??

it can be the fuel pump (FP) or it could be the fuel pressure regulator (FPR).

it could be that your ignition module (aka TFI), is on it way out too.

or combination of things .

best to start with getting fuel pressure readings, it should be somewhere between 30-40psi . Also a quick check on the FPR is to pull the little vacuum line off the rear of the FPR....if it dribbles gas out of the line...it is done, the interior diaphragm has a leak. If fuel is present in this vacuum line, make sure your oil level is normal or the oil doesn't smell like gas.

as for the TFI it can be removed and tested as well at most parts stores.
& couldn't hurt to get the codes either.

Fuel pumps
As you cycle the key ON, (not all the way over to starting position)...can you hear the FP prime up breifly, 1-3sec. you should get this with every cycle of the key to the on position.
if you can not hear it...then your frame rail pump is suspect...either it isn't getting power or just non functional.

the intank pump is a bit tougher to determine if it is working and needs the aid of a buddy. One needs to get under the truck and place a hand on the tank or a rod or tube on the tank and the other end to your ear. Again, cycle the key just to the on position and off, you should be able to feel the tank vibrate a bit or hear it turn on with rod/screw driver/tube. Unfortunately this only determines if it is turning on and off. to see if it actually moves gas requires removal of the hose before the main pump on the frame.

now if the fuel line is leaking... this very likely accounts for the increase in consumption...I suspect that you did not travel with the line leaking as you described earlier....it maybe because it wasn't fully seated to it locked position?

 

[fordman4488]

I know that when my pump went out on my F150, i did get about 20 miles less to the tank right before it went, but check your fuel lines, all connections, and FPR first like IMenriched said. Also, if you changed your fuel filter the day before, it could be your fuel pump, in past expirience, if your pump is weak and you change your filter, it can cause it to fail, don't know why, but have seen it happen a couple of times.

 

[foss40z]

Got er Done... It was the Fuel pump on the chassis.. I turned key over and i heard it at first, but i did it a few more times and nothing. So i pulled it out and hooked it straight to a battery and nothing. So I tapped on it and it started to work, then stop, then work then stop. So replaced with a Airtex pump and walla. Truck is running, Power is back. W00t .. Thanks for the Input guys, Much appreciated..

 

[fordman4488]

Glad you got it figured out, and quick. Props

 

[AllanD]

FILTER FIRST.

Don't even TRY to diagnose a fuel system "problem"
(unless the pump does NOTHING when powered)
until you've replaced the filter.

Your symptoms sould to me like classic colgged filter symptoms.

The crap gets blown up against the element when you are running
wand when you shut it off and the pressure bleeds down (typically leaky fuel pump non-reverse valves)
and the crap falls off the bottom of the element to the bottom of the filter.


AD

 

[jaymegriffiths]

I changed fuel filter the day before

Mr.Foss

FILTER FIRST.

Don't even TRY to diagnose a fuel system "problem"
(unless the pump does NOTHING when powered)
until you've replaced the filter.

Your symptoms sould to me like classic colgged filter symptoms.

The crap gets blown up against the element when you are running
wand when you shut it off and the pressure bleeds down (typically leaky fuel pump non-reverse valves)
and the crap falls off the bottom of the element to the bottom of the filter.


AD

... confirmed to be the pump. also, i changed my filter and i believe my pump is goin. difficult to diagnose until i get the tank switch fixed...