fuel cap sensor

[mwood1985]

i have a 2001 4.0 i think my fuel cap is bad it keeps popping the check fuel cap guage and eventually the check engine light i tried taking it off and putting it back on like the manual says but it wont stay off do i need to just replace the cap or what

 

[Ranger44]

Try just buying a replacement cap.

 

[mwood1985]

oki got a new cap and the light stayed off for about 50 miles of driving now its back on anybody got any other ideas on whats wrong and how to fix it?

 

[Wicked_Sludge]

you have an evaporative emissions leak. for one reason or the other,your fuel tank is not completely sealed. the usual cause is a user failing to install the filler cap after fueling up...but this obviously isnt the case here.

finding the leak on your own will be tricky...dealers use special equipment for pressurizing the tank and monitoring leaks.

 

[mwood1985]

ah peachy i guess im not fixing this one. im kinda wondering what would cause this. just so i dont let it happen again the ford dealer quoted me 80 bucks for just the pressure test not cool but got to be fixed be for the danger ranger becomes an exploder lol

 

[Quiksurf]

evap leaks

the first thing you need to do is a good inspection of the fuel system. no not the pump and fuel pressure lines, but the evap lines. check the purge valve vacuum source located in the engine comparment, i believe it is the white vacuum hose the valve it connects to has one electrical connector, one small vacuum line, a large line connected to the intake and a large line connected the the fuel vapor recovery lines going to the tank. the small line can break and trick the pcm into thinking it has a large leak due to not opening the purge valve. next check the vent solenoid/ valve, thats the one in the back i think over the spare tire. the valve should be open with no voltage applied, and blocked with voltage applied. check the pins in the connector for corrosion. if neither of these two help you should take it to the dealer for a "smoke test". they close the vent solenoid, via scan tool and pressurize the tank with smoke, the smoke comes out and voila the leak is found. if it is a large leak p0457 or p0455 you may be able to smell the fuel vapors, but not likely.

 

[Hazmat Ranger]

You may also want to consider checking your fuel filler hose. Mine cracked and began leaking at the top of the line, where it attaches to the filler neck on the bed. It also leaked fuel when the tank topped off and the overflow ran back to the tank. I fixed it with a new hose . . . just a thought if all else is good.