fuel issues game plan.. need to brainstorm.

[Dano!]

Hello everyone.
well it always seems like you fix ten things before another important system goes down. i drove home from work went upstairs to change out of uniform and went down to the Navajo and it wouldn't start..

Identified my problem. no fuel getting to the engine. the only fixes at all ive touched to the fuel system within a week of this failure is replacing the fuel hose from where you pump gas to the gas tank. it had a huge tear in it. this is the first time that my Navajo has run on a full tank of gas since i bought it in January.
so like usual i had my brother in law tow it from base to the mom in laws and jumped right into it trying to figure stuff out.

luckily i already had a new fuel pump and strainer on hand. (part of my paranoid theory that everything will go wrong with this truck until i am the one fixing it.
unhooked fuel lines starting from the engine and tested for pressure, worked my way back to the fuel pump. dropped the tank and replaced the super old nasty fuel pump/strainer put a clean "new" used tank on (because i didn't know what kind of stuff made its way into my fuel tank with the huge hole i had in the line.)
put it all together and i had pressure to the engine.. when i got the truck running it would run ok while idling, as soon as i drove it though it would sputter out. i suspected a clog or obstruction somewhere so i replaced the fuel filter and the fuel regulator (the metal screen in the regulator was raddeling inside of it.)
if i give it some TLC i can get it running.. but i cant drive it without it dying. because i can get it running i assume that everything in the system is ok mechanically.

either i have an electrical issue. or the strainer on the fuel pump isnt sitting in the groove on the bottom of the fuel tank and folding up against the fuel pump. causing the strainer to collapse and restrict fuel flow..

does my reasoning sound right? the truck is in another state and ill have to wait to have a free weekend to get back over there to work on it. i just want to have a game plan to use my time effectively.

if anyone can help me build this game plan or offer advice or more information. it would be awesome. thank you guys.

-Dano

 

[MrShorty]

Fuel issues could certainly cause the problem you are seeing. First thing I do when I suspect a fuel system issue is to put a fuel pressure gauge on it and see if there's a problem with the fuel system.

 

[huntman58]

When testing the fuel pressure make sure your testing it at the fuel rail test port with every thing still hooked up. Test idle, high RPM, and static/ holding pressures
Also check for fuel in the FPR vacuum line at the Vacuum tee on the intake manifold or at the FR it’s self.
Check /clean the pump relay contact blades and make sure the relay is good you can do this by swapping the AC relay for and with the fuel pump one.


Now results and what to do
Bad relay = replace
Gas in Vacuum line = Change FPR (Fuel pressure regulator)
Low pressure at idle = Check fuel filter, FPR
Higher then normal pressure at idle = Check vacuum line to FPR
Low at high RPM = check Vac line, filter, FPR, Pump
Static/ holding pressure = if it will not hold pressure = check FPR, Fuel pump check valve.

The system is kind of simple when broken down in to parts.

If you’re getting power at all times then it’s a flow issue so work from the motor back being the FPR can and normally dose cause the most problems from not holding pressure to not allowing enough pressure to leaking fuel in the vacuum line. The next one would be a dirty filter but you said you changed that already so the next step would be a possible bad pump.

This is just MPO and what you do or do not do with it is your call but no matter what

 

[Dano!]

Fixed my fuel issues and it will be found on this thread. VV

http://www.explorerforum.com/forums/showthread.php?t=298272