Check Fuel Cap Light

Hi all,

for the past year or so I've been wrestling with my "check fuel cap" light. I've replaced the fuel cap around 3-4 times which fixed it for about a month each but the light still returns after then. It's driving me nuts because I hate seeing warning lights on my dash. Please let me know how to correct this problem.

Thanks,
Brandon

maybe fix

I had this same problem, replaced a couple caps. I found that if I tap my fuel cap on the bumper to "unstick" the float or whatever is in the fuel cap, I never had the problem again. It's just habit for me now. Haven't had the issue in a couple years.

I have never replaced mine but every now and then it turns on. I think its because I am not putting it on correctly but it doesn't really bother me. (I actually got a gas cap for my car at the junkyard 2 days ago since mine broke in two, so I am curious to see if the check fuel light will shut off when I replace it)
Another factor that could be turning this light on could be a crack near the filler neck of the fuel cap. My friends 98 sport check fuel light was on for the longest time and he had somebody check it out and it turned out he had a crack near the filler neck. He took it to a mechanic and they used some sort of filler made specifically for cracks in the filler necks and it turned off about a week later.

My filler neck was also rusted out on my 02. 3 other cars of mine had same issue and confirmed fixed by replacing / repairing filler neck. Could find a replacement at a junk yard. To check it, remove the filler neck & plug off all openings and install a cap. Should easily hold pressure as you blow into or suck on an uncapped opening.

I believe it's a closed loop system. So any hole in the vapor containment system allowing air in may be detected as a loose fuel cap.

.

Number4,
How do I check this? Is this something the shop needs to check for? (Holes in the vapor system that is)

mbrando1994 said:

Number4,
How do I check this? Is this something the shop needs to check for? (Holes in the vapor system that is)

Click to expand...

Never had too. I'd start by just inspecting for cracks or holes. The vapor canister is hard to get to, but its plastic. If you can follow all the lines, I'd do that. Check the easy areas first.

Suggestion

Hello, As Number4 said, do as complete a visual check as you can.
A smoke test is next.

I don't know about these Fords as I'm a helper-outer with my friend's '97 F-150 and his son's '04 Explorer but on many GM cars I've seen there's a tagged fitting under the hood for a smoke machine.

If I was seeking a leak I'd round up 3 guys with lights and start the smoke machine. Have the scouts all over the car looking for wisps of smoke.

That the filler neck was mentioned here a couple of times makes it a good place to start. Kira