Gas Pump Keeps Stopping When You Fill Up? Diagnosing Fuel Tank and EVAP Blockages!

Does the gas pump keep stopping over and over while you're trying to fill up? You know it's not full, so what else could it be? In this video, Andy diagnoses this very problem, and explains how the charcoal filter canister that is part of your car or truck's EVAP system could actually be responsible. Since the fuel tank is a sealed container, when you add more gas, air is pushed out. If the air has nowhere to go, the increase in pressure triggers the safety stop on the fuel pump! Watch this video to see Andy demonstrate how a blocked charcoal canister can cause this problem!

For more great diagnostic videos, check out this playlist:

⚠ DISCLAIMER:
While 1A Auto strives to make the information provided in this video as accurate as possible, it makes no claims, promises, or guarantees about the accuracy, completeness or applicability of the content. No information contained in this video shall create any expressed or implied warranty or guarantee of any particular result. All do-it-yourself projects entail some risk. It is the sole responsibility of the viewer to assume this risk. 1A Auto is not responsible or liable for any loss damage (including, but not limited to, actual, consequential, or punitive), liability, claim, or any other injury or cause related to or resulting from any information posted in this video.

[AAuto]

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[nickcoppolino]

THIS IS MY TRUCK!! I bought this off you guys and it still has a check engine light on for my evap system

[sethdover]

Navy mechanic here. It's rare for it to actually be the charcoal cannister, usually it's the vent line needing blowing out. But when it is actually the charcoal cannister as the problem...it's because you keep clicking the gas at the end trying to get every drop you can in the vehicle! That causes fuel to reach the vent line and trickle back into the charcoal cannister and stop it up over time. When you're fueling up, stop continuously clicking the fuel trying to get every drop possible! Maybe do it a couple times and stop, and you'll never have charcoal cannister problems.

[ntgrace]

God I love you guys! Thanks so much Andy, I have a small (MOM & POP) car lot and have to do 99% of repairs myself as well as be the salesman. Your videos has helped / saved me so many times as well as saved time and money. I have become a 1A auto customer, most my local parts store no longer deliver nor do they seem to carry many parts. they tell me they can order parts needed, so I came to realize that I can order parts ( FROM 1A AUTO ) )as easy as they can for a much cheaper price from 1A. THANK YOU AGAIN AND I REALY APPERICATE THE HOW TO VIDEOS

[beehappycoleman]

May I ask how much the average cost is for this kind of repair at a auto shop? Thank you for the very well detailed video.

[TheHouseofChameleons]

Gas prices have prevented me from filling up my tank.

[dwightdeguzman]

I had this issue with my 2017 Silverado recently. Thanks for the informative video.

[ChristopherHenneman]

Nice video. This was by far the clearest explanation of the evap system that I've come across. Thank you.

[ussir]

Excellent detailed show and tell! Thank you. Will be using it as a guide for my truck's gas filling issue.

[RCCustoms]

Watched this video and one thing not mentioned is that this is and remains a common issue for Chevy trucks which is what he's working on. Another design flaw by Chevy was and is the short run of the filler tube and the bend in it. I've seen brand new Chevy trucks do this and obviously there was no blockage in the canister.

[OliviaSST]

Very well presented video of a common problem in a wide range of vehicles. I also have that problem with an Avalanche and a Hummer H2 including the check engine (MIL) light and a P4520 error code (Evap Code).

[MyLifeThai]

My 2005 Ford Mustang has always kicked out the pump and I have had to trickle gas into it, since I bought it when it was only 4 years old with 36, 000 original miles.

[roccotaco]

Love the video!!! Perfect presentation and made swapping my 2005 Sierra parts as easy as it gets. Keep up the great work.

[oxwtvnl]

Thank you so much for this excellent video.i have the same issue happening so I filled up gas container and then i poured the gas into the car.

[mikenorman]

I don't know if that's the problem but you gave me a few ideas I'm having a similar problem on my 5 series BMW

[mckoylach]

Thanks for the video. I have this problem with my 05 murano

[deankay]

The activated carbon in the canister is sized to the fuel tank. The Marine is correct that pumping the last drop can cause the filter media inside the canister to tear as it’s under spring pressure. This leads to black carbon chunks in the purge line up to the valve & engine.
The A1 Auto tech diagnosed the symptom but not the root cause. The fuel tank solenoid is open all of the time until the PCM runs an EVAP test after 4-6 hours of drive time at temp. Since it’s open, allowing air in, it has a foam filter in it or separate like this one. East to open with pocket screwdriver and dump a pound of dust out. This plugs canister way more often than anything. If the tank solenoid can’t close durning an EVAP test, a code for small or large leak will set. A loose gas cap is common. The filter could be cleaned, but replace it if you can afford it. Two wires, one or two hose and if you see thru it, spray WD-40 and quickly blow compressed air thru it. Installing rubber hoses is easy if WD-40 is sprayed, all hoses. That’s all I use it for! Ever. OBD-2 codes are in 4 categories but concern yourself with “B”. Codes in “A” turn light on now, type “B” detected problem like small leak, if refueling and 2 gallons or more added, time to run test, it shows “Check Gas Cap” this is how & type “B”. If Crooked or loose, drive, park, coolant & air temp within 10F of each, drive to temp, runs test, passes! Now repeat 40 more warm-up cycles, type “B” code disappears, congrats! OBD-2 is complex computer software and once engine is started, it takes 3-6 minutes to check everything. Complete understanding is hard but I learned it in shop, then taught it for almost 7 years in 7 or 8 states for up to 100+ techs!
Best of luck! ASE Master 78 + L1

[raka]

Hi, thanks for the video.
Does it make any difference with drive or consuming more fuel?

[aa-lggo]

Thank you for your time and effort you put into making this video.

[Tony-ijzx]

I had a half tank gas when I decided to top off prior to entering the Gettysburg battle field for a tour. I only Got about a dollars gas in when the nozzle started shutting off and spilling out gas. I couldn’t get any more gas in. (2019 Jeep Cherokee). Called a Jeep dealership and they recommended bring in the car. Decided Toft to our destination and see what goes. Tank should 3 quarters empty when I pulled into a gas station. Holding my breath, I had no problem topping off the tank. Car ran fine rest of trip. Gonna try again when at half a tank just to see what happens before i take to the shop. 🤞🤞🤞