Troubleshoot gas pump shutting off during tank fill up on Chevy truck 

Awesome. I’m glad it helped!

I have the same truck and same issue

@@chrisricks9583 I’m still dealing w it. Thankfully I only hand yo put gas in ab once a month

@@arfarms5711 did you find the issues for yours? I changed both parts and I’m still dealing it.

I changed my charcoal canister. It worked. Don't over fill you gas tank

Glad you found it helpful!

I changed all of that on my 07 avalanche and still having the same problem

Did you ever figure it out because I replaced both the vent valve and the charcoal canister and it’s still having fill problems

@@emeraldwordcool1023 Yea I was able to fix it. Ended up being the media from the old charcoal canister backing up and getting into the lines and tubes that vent the fumes from the gas tank to the canister and vent tubes. I Found out this was pretty common in these GM’s. We had to drop the tank set it on a bench and blow out all of the lines from all different sides and ports. A lot of the charcoal beads were flying out everywhere. It took about a good 20-30 minutes of blowing air through all the the hoses and lines that were attached to the gas tank. Went ahead and reinstalled everything and put in a new charcoal canister, and finally I was able to pump gas without any problems. Did it just about 1 year ago and still haven’t had any problems. I hope this helps. 👍🏽😎

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Thanks for the comment, Wanda. My canister had a foam barrier inside that keeps the charcoal from backwashing, and the foam had deteriorated, so I needed a new one. The charcoal was floating back up the vent lines toward the tank.

Dude where???

can you explain how to do this? thanks

Replacing the canister fix it for me. If you are still having problems, then it is probably clogged lines from your tank to the canister.

I’m not exactly sure on a second generation avalanche. I think if you find the charcoal canister and work your way backwards and forwards from there, that should give you a search strategy

It’s on top of the motor if it is like our 2007 tahoe.

If you pump the tank to full and the gas pump then cuts off, you will get a little bit of gasoline dribbling out onto the ground. It's normal for a little bit of gasoline to go down the lines into the vapor canister when you top off. This is a good way to see that the lines are clear (seeing some gas on the ground after filling up with the lines disconnected).

Yeah, I believe what happens when you overfill is that gasoline flows out the vent tubing and into the charcoal canister. There is a foam barrier at the canister entrance, but it disintegrates over time. Then the liquid gasoline that flows into the canister washes back into the vent tube, carrying charcoal pellets with it. These pellets clog up the vent tube and have to be blown back out.

the gas vented directly to the air via a air line that ran alongside the down spouts.. from 1920-till 2001 , before they mandated EVAP systems post2000. california made that no longer possible..

Good luck. Try just disconnecting the line to the canister and let it vent freely to the air first and try gassing up. That way you’ll know without throwing parts at it.

Arthur, did it work after all. Fixed it. I have same problem. I already did the first test. This weekend or once I can, I'll be trying the second test with rhe charcoal canister. And then the lines. This way I'll know my lines are not clogged up.

@@treyspetch Hypothetically if one was to leave that connection disconnected, would there be a code thrown or any problems other than the obvious one?

@@kevinspahr6632 Yes, the vehicle periodically goes through a diagnostic test where it closes the valves and tests that the system is sealed. With a vent tube is left open to the air, you will fail that test, and it will throw a code. But this has absolutely no impact on the health or performance of the truck. It only means that your vehicle is venting some gas fumes to theair without running them through a charcoal filter dictated by emissions standards. HOW DARE YOU!!! ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-xVlRompc1yE.html

@@trey5630 Yeah that's what I figured. Mine is actually doing it on an 04 Chevy Venture. I'm hoping I have the same set-up as your truck. I'll wait till the weather gets warmer before I take a look.

If you disconnect all that and it still stops, then your vent lines are clogged and you need to blow them out.

No, I have done this. The worst that will happen if you get a little triple of gas on the ground when the tank is full. That’s the gas that normally with triple into your charcoal container.

The pump will still shut off when the gas work his way back up the filler neck.

treyspetch thanks!

There is a check ball at the top of the tank. Liquid gas should never go into the evap system. If there is, there is another problem, and the charcoal canister will be bad because of the liquid gas.

@@jasonsprouse2803 The check ball is a rollover protection. It only blocks the flow when the gas tank is upside down. If it activated all the time, the rush of air out the vent hose would be blocked, completely invalidating the idea of a vent hose. Liquid gas goes right out the vent and into charcoal canister when you overpump. Give it a try by disconnecting your hose from the charcoal canister and you will get a pool of gas on the ground when you pump the gas beyond full. The charcoal canistetr can take a little bit of liquid gas. This is why they tell you not to pump beyond when the pump shuts off, because it dumps more gas into the canister, where it floods it and it takes longer for it to evaporate.

I'm not sure. The foam insert that keeps the charcoal from going out the inlet nipple was all disintegrated. It was 16 years old. Not sure if it was from overfilling too much.

Trey I’m about to do mine on my 16 yr old Escalade. Same system. Thanks man.

@@joeculpepper2235 could be driving on gravel roads? It's happened to me on 4 different vehicles now in the last 10 years and I've only had 6 vehicles in that time, I drive a lot of gravel roads, do you often travel on gravel or live in a dusty area? I'm in farm country mn tons of dirt kicked up so I'm assuming that dust is the cause of the problem. If anyone is in a city and never drives gravel and still has this issue, let me know. I'd like to figure it out too

Yes it’s very possible that charcoal pellets have floated back up into that hose and clogged it. It happened to me once. I found a very small 1/4 inch line coming out of the back of the tank that think led up toward the filler neck. It had a little disconnect in the line. I disconnected it and blew compressed air through it to inflate the tank. About 1/2 cup of charcoal pellets came blowing out of the vent line that goes to the canister. After that, I Hooked the vent line back up to the canister and everything was cool. Some people say that this is a consequence of overfilling your tank by continuing to click after the pump shuts off. I think the idea is that fuel flows into the charcoal canister and then back washes into the line carrying charcoal pellets with it.

And make sure you keep the filler cap closed, so the tank will hold the pressure when you blow air into it.

treyspetch I suctioned lots of carbon debris out. Still not working. I now recall in the past that when this began, at one point when I was trying to “rapid fire” fill my tank that fuel actual spilled out at one point. At the time I figured that the evap system shutting of the filling caused stoppage of fuel intake, but now I wonder if it’s a problem in the first stage of the fuel line, from the top (the neck) down to the tank. How common is that? Might be time for me to give up and take it into the shop? Appreciate your comments and suggestions. Was fun while it lasted

@@michaelcronin8253 I’m not sure if suctioning out really provides enough force to clean the line out. I think I would take compressed air and blow it out from the other side to ensure that there’s nothing still stuck in there. It just requires a compressor.

treyspetch The issue there is that I think I’d need to drop the tank to get to the other end of the line, correct? That’s a bit beyond my capabilities I think

That’s normal. When the tank is full, it sometimes overflows our through the vent line into the charcoal canister. If you disconnected it to test, it will spill a little out into the ground.

Yeah, my guess would be its the lines that are clogged or the valve will not open.

@@trey5630 okay, my lines is clogged up my mechanic said

@@trey5630 he said my value is good

@@lauradinkins On my 2004, there’s a very small line near the very back of the tank there’s a fitting that you can disconnect in the middle of the line, and you can put a compressed air gun against it to blow air into the tank and blow those vent lines out. If you can do that, it saves you from having to drop the tank down to get those lines out

@@treyspetch I have a Hyundai Elantra 2002

During refueling, the vent valve remains in the normally open state to vent the air from the tank. That’s what allows you to add gas. When the valve gets stuck closed or the vent lines become clogged, the gas backs up in the filler tube because there is nowhere for the air in the tank to go. The purge valve is closed when the car is off.

clogged vent lines

@@trey5630 do you have a part number for that or just say I need the vent lines between the solenoid and the charcoal canister

I don't know the parts numbers. You can get the vent lines between canister and solenoid off yourself pretty easily and blow them out. The lines from the tank to the canister are harder to get to, and most people remove the tank (lots of work, never done it).

@@trey5630 thank you your video and advice has been a great help

Glad to help. Later on I had another problem where the bad charcoal canister sort of burst inside and charcoal particles got sucked back into the vent line toward the tank. I was able to blow out the tank with compressed air while the charcoal canister was disconnected. About 1/4 cup of charcoal pieces cane flying out. After that there was no more curling problems.

That's crazy whoever came up with that system is a real asshole

I just bypassed the whole entire Box altogether

@@chevyvet69 how?

@@chevyvet69 at what point did you disconnect things? and the vapors venting caused no problems with anything?

its always the charcoal filter. that is why they installed tehm after 2000. its a $300 repair every 38-48 months or no gaz4u

You probably have carbon pellets in your lines, and they need to be blown out

That sounds like your computer is malfunctioning and sensing pulse to your solenoid. Or the solenoid is going bad.

If you replaced the solenoid and the charcoal canister, then it is probably a clogged vent line between the tank and the charcoal canister. If your canister went bad, charcoal bits can float back into it and clog it. Disconnect it from the charcoal canister. Keep fuel cap on. Find the little quick disconnect fitting on the little line near the rear of the tank that goes up to the filler tube. Disconnect it and blow compressed air into the tank. In my case, about a quarter cup of charcoal bits came flying out of the line to that goes to the canister. Clog fixed.

Ive done everything minus replace tank same think sometimes makes worse been to mechanic 4 times Friday reblew lines couldn’t put gas

@@tonygg1989 Hmmm. Not sure what else could be causing this. Other components can cause evap system faults, but the vent is pretty much just the tank, vent line, canister and solenoid valve. I would be second guessing the mechanic...What happens if you get under the truck and disconnect the vent line from the charcoal canister? Then drive like that to the gas station and try to fill up. The tank should be freely venting right out that line onto the ground. You'll have a little spill of gas on the ground when the tank gets totally full, but no big deal. If it still won't fill, then I would suspect some sort clog in the vent line or the filler tube.

@@tonygg1989 I've heard ya take an air compressor and then open your gas cap, then blow out that gas vent line but make sure your gas cap is off first. Haven't tried it yet but it's the most common problem from what I understand

Any code ? Like p2422 valve stuck close

Disconnect the lines from your canister & vent and trace that hose from the canister to your fuel tank and disconnect that line, then just blow compressed air thru the lines. You probably have charcoal clogged somewhere. You may have a clogged vapor canister purge valve too. It’s under the hood so check it to be sure. After that, it should definitely work… That covers all bases to the issue.

All of this stuff is required by the federal government for emissions standards. The charcoal canister is required to scrub and capture the gas vapors on every car, where the air in the tank has to vent out when you fill it. The valves are required to then close the system to allow the engine to suck them back out of the canister and to do the emissions test, which the government also mandates.

Then it’s clogged vent lines between your tank and the canister.

@@treyspetch i’m pulling off the filer line right now to check the flapper then i’ll blow out the other lines

@@treyspetch I also took the lines off the canister and the solenoid to try and fill up that way and still same issue. even with the lines detached it won’t fill

@@treyspetch blew out the line from the fuel pump to the canister. Completely filled with charcoal. works fine now

@@cali_misfit1387 Ah, I'm glad you found the problem. When my charcoal canister got really old, the foam barrier that keeps the charcoal pellets inside the canister disintegrated. Then when gas flowed into the canister on overflow, the pellets back-washed into teh lines and clogged them. Sounds like same problem with yours. You might want to check your canister inlet to see if the foam is gone, so it won;t happen again.

This is for full size Chevy and GMC trucks. Do you have one? It’s right above the differential, ahead of the spare tire.

@@treyspetch yeah I can’t find it in the part store they always have a different one

@@robertsestate6421 try Amazon prime

@@treyspetch thank you I’ll try

Yeah, ok. I’ll get right on that. You should definitely get your money’s worth on my video.

I could see just fine if you have any mechanical inclination you know what your looking at not that you can't see in the video.

Always that one asshole lol.