Gas Cap issue / Fuel Filler issue

I have two issues that popped up in the last couple of months and I wonder if they could be related:

1) CEL came on about 3 months ago. Ran diagnostics at AutoZone, came back "loose gas cap." This seems to be a common theme. Regardless, gas cap was on fine, and CEL remains on.

2) Before all this, I've noticed my fuel filler is less likely to hold a gas nozzle without turning it off: i.e. when I engage the hold open clip on the nozzle, it will pump gas and then click off like it's finished almost immediately. This has happened at multiple locations and again, has become more and more an issue. I can typically only fill up if I click the hold open clip and told the nozzle, usually up at an angle.

I'm wondering if the two might be related. My first instinct is to replace the gas cap and see if that handles the first issues, but probably not the second issue. So, ultimately I might have to focus on the second issue, but I'm unsure where to start. I will add, the previous owner (brother) had a small fender bender but that was very small and ages ago, and they did not have the same issues with fueling.

Thanks for any and all help.
Sean

 

Fuel filler neck has a vent to it...

they can get clogged.........or more likely get kinked...

If so it will take you forever to fill up...

that attaches using rubber hoses at its bottom.


The not so easy fix is if something is wrong with tank vent, or your vapor canister is acting up, like one of its valves is stuck/bad....

 

Thanks for the reply MD.

I'm open to replacing the unit, but maybe not immediately. First question is, is it unsafe to drive?

 

No, problem is getting gas in...not out..

This a good reminder......DO NOT OVER FILL YOUR TANKS.....never past 7/8 mark..

especially 02's and later.....that can flood your charcoal canister ruining it...

those start around $400 now....and a pia to troubleshoot



And gas caps can go bad and start throwing codes......nothing lasts forever...


It is rare the filler neck goes bad .....sometimes cracks near the top....
more likely its the rubber hoses at the bottom...


I've replace everything rubber on my truck......cept those two hoses....
which I will acquire thanks to you poking the subject...

 

It could be an issue with the Vacuum Switching Valve under the hood between the brake booster and the battery.
Can you tell us what code or codes you have?

It should be safe to drive.

Have you noticed a fuel smell?

 

@ 8:00 min.....

https://www.youtube.com/watch?v=QZZdqQRKH6M

 

All good points.

Hadn't heard this before. To clarify, you're saying don't fill up completely, or be cautious in filling beyond capacity (i.e. don't top off when it's full)?

 

Didn't get the codes when done at Autozone but will stop by and re-do. I've been meaning to do that in case something new is triggering CEL. Will report back.

And no, no fuel smell thankfully.

 

With a 2003, look at your evaporator system, this isn’t a cap issue

 

I always stay 1/8 tank from the top...
and consider 1/4 tank empty...

these parts are old, expensive, and pia to diagnose


dropping a tank.......is like a day in hell....


everything's stuffed up against the frame rail with no room...

 

yep OS is spot on

if gas pump stops…..don’t add more
Over a Period of Time……that top off of fuel will allow small amounts to overflow into emissions hose leading to charcoal canister. Tablespoons add up over the years

 

Codes:
P0456 EVAP System Leak Detected (very small leak)

and

Secondary DTCs:
P0442 Evaporative Emission System Leak Detected (small leak)

Initial online search says that these codes are as general as they get, so any experience/advice is appreciated. I'll probably just start with a new gas cap and go from there.

Good news: no new codes popped up.

 

Evap codes are generally 2 trip codes.

This is a better explanation than I can give.

https://trade.mechanic.com.au/news/trips-vs-drive-cycles-what-s-the-difference