I have a 2001 Ranger off road 4.0 and the fuel cap light on dash keeps coming on. I have replaced the fuel cap and it stayed off for about a month now it keeps coming on unless I pull the battery cables, when I do this it will stay off for about three or four days then it comes back on. Is there a sensor that could be bad, if so where would it be located. You have to fill very slowly, I know the filler pipes have to be changed would this cause the light to keep coming on?
Any help in this matter would be greatly appreciated.
Thank you,
Looper2001

 

Yes, most likely an issue with filler pipes

Vehicles have an EVAP system on the gas tank, this system seals the gas tank when engine is running and applies some engine vacuum to the gas tank, a slight negative pressure so when gasoline sloshes around in the tank when driving any fumes are sucked thru a charcoal filter and then into the engine to be burned, instead of polluting the air

Gas cap light means EVAP system can not hold negative pressure in the gas tank, so first thing to check is the gas cap, was it left off or is it tight
If gas cap is OK then there is a leak somewhere else
Filler tube maybe or one of the EVAP system hoses

While its a pain to do, pulling off the bed of the truck may be a good idea in this case, to replace the filler but also to check the EVAP system and hoses, its behind the gas tank under the bed, hard to get at from underneath

 

Thanks for the response, I will check evaporate system for leaks.

 

You can do this if you have a helper

Get a short hose and damp towel
Engine and key off
Remove gas cap
wrap hose with damp towel and put end of hose in the gas tank and seal it with damp towel
Blow into the hose
Tank should hold a bit of pressure...............if there are no leaks
If there are leaks you should HEAR the air escaping from those leaks

DO NOT use an air compressor for this, you WILL blow off EVAP hoses
Human lungs can only generate maybe 2psi pressure so won't blow off any hoses or fittings


If you have had this Ranger for awhile you will probably remember stopping for gas and when you removed the gas cap you would hear a "WHOOSH" of air being sucked into the gas tank, that is from a working EVAP system holding a slight negative pressure in the gas tank, so no leaks
You probably haven't heard that noise since the "gas cap" light has come on

 

Thanks for the advice, I haven't had a chance to try it yet.
Looper2001