lean codes

[steve wilson]

i have a 1999 explorer sport 4.0 soch auto.hve two fault codes p0171 and p0174..i have replaced upper and lower intake gaskets, injector o rings,fuel psi is at 35 at idle... ran soke test and no leaks.... any help would be thankful

 

[Mebob2001]

i know my 2001 SOHC explorer had alot high fuel pressure then that, check driving fuel rpessure see if ti drops off, could be a weak fuel pump, but before going there make sure the fuel filter is clean or bin replaced recently, no collapsed lines... ive replaced alot of fuel pumps from people running the car's low on fuel and or never changing the fuel filter... remember the fuel pump uses gas to keep it cool and lubracated, but 35PSI seems was to low if you ask me

 

[2000StreetRod]

replace filter then pump

i have a 1999 explorer sport 4.0 soch auto.hve two fault codes p0171 and p0174..i have replaced upper and lower intake gaskets, injector o rings,fuel psi is at 35 at idle... ran soke test and no leaks.... any help would be thankful

In 1999 Ford switched to the returnless fuel system. Your fuel pressure should be about 65 psi at all engine speeds. I suggest that you replace the fuel filter (it may be blocked) if not done in the last 50K miles. Then check your fuel pressure again. If still low, remove your fuel pump and check to see if the internal hose is split. If not, replace the pump.

I am convinced that lack of filter replacement at the suggested interval shortens the life of the pump.

 

[jimbalaya]

In 1999 Ford switched to the returnless fuel system. Your fuel pressure should be about 65 psi at all engine speeds. I suggest that you replace the fuel filter (it may be blocked) if not done in the last 50K miles. Then check your fuel pressure again. If still low, remove your fuel pump and check to see if the internal hose is split. If not, replace the pump.

I am convinced that lack of filter replacement at the suggested interval shortens the life of the pump.

I agree with The Rod; i had those two codes a few months back and after several other attempted fixes via replacing other parts, it turned-out to be the fuel filter which was partially blocked with crud.

 

[steve wilson]

i checked fuel psi today and before fuel filter replacement was a constant 37 psi
changed filter and jumped to only 39 psi. ordering a factory fuel pump and will update after installation of fuel pump...
thanks

 

[joe doe]

did you replace the intake plenum orings??

look at this photo ..

the pieces on the bottom .....when these go soft thats when those codes are thrown .if you did not do these those codes will not go away .these are between the upper plenum where it attaches to the lower intake .

 

[steve wilson]

i replaced upper and lower with ford gaskets then resmoked.. no leakes
thats when i checked fuel psi b4 and after i changed fuel filter
ordered ford fuel pump.

 

[JusTheUsual]

I replaced all those gaskets before on 2 of my explorers, people here and ford dealership kept sayin its those gaskets, nope, it ended up on both of them being fuel pump AND HEADS/head gaskets, good luck on it just being fuel pump

 

[steve wilson]

installed new ford fuel pump today. after installing fuel psi went to 64 psi cleared codes
and road tested no fault codes returned.
thanks to all who helped

 

[2000StreetRod]

congratulations!

You can extend the life of the new pump by changing the fuel filter again after another 50K miles and not running out of gas. The fuel cools the pump and it should not be run dry. Congratulations and I hope you have many years of dependable service.