Thanks to everyone for useful information! Please help with some advice.

I have a 2004 Hyundai Sonata Base 2.4, 90k. Some time ago the gas pump started to shut off when refueling, the problem got progressively worse over the next several refuelings, and now shuts off almost immediately, can't get any fuel in.

I brought the car to a mechanic, and meanwhile researched the problem online and found this thread. The mechanic called and said that they couldn't identify the problem and need to drop the tank to establish the cause, which would cost $300. I refused (I didn't want to spent that much at that point). When I picked up the car, I asked what they were able to find out. The mechanic said that they "smoked" the system, and all the filters and hoses were working fine. I then specifically asked if the charcoal canister and the fuel vent valve are ok (because the mechanic didn't mention any parts by himself), and he said that yes, everything is fine, because the system passed this "smoking" test.

My questions are: could they really check everything by this "smoking" the system without carefully checking everything as outlined in the first post? Without even removing the charcoal canister? Does it seem like they know what they are doing? Is it really possible that my problem is something else and they will find it after they drop the fuel tank?

My suspicion is that the answer is "no" to all those questions. So what should I do? Take to another mechanic? Do you think it might work if I show them the instructions in this thread and just ask to examine and possibly replace the charcoal canister? Maybe even ask them to do the custom job and clean the Fuel Vent Valve without removing the tank, as described earlier? Would the mechanics react favorable to such a request?

Would appreciate any comments and suggestions. I really don't want to spend several hundred $ for a repair on this car, which has many other problems and doesn't cost much. But I would even consider that - but when they tell me they still don't know what the problem is, I am afraid that removing the tank would not be the end of the story, and they will do a lot of work on the car, charge even more and still won't solve the problem.

 

The "smoke" test will only find a leak. The smoke test was totally pointless for this slow-fill problem because this issue is caused by a clogging. The smoke test won't find a clog.


So, no, they could not have properly (or even remotely) diagnosed this slow-fill issue via a smoke test. I hope they didn't charge you much for a totally useless test.


Unfortunately, if you are unable or unwilling to do this yourself, you are basically stuck paying outrageous prices from a shop. I don't think you'll find a shop willing to cut your interior paneling up to access the vent valve like somebody described doing earlier in this thread. Perhaps you could, but I would bet they'd charge you just as much as they would to drop the tank. $300 to drop the tank seems very, very high. It's not that much work, especially if the shop has a lift. Although for all I know that could be the going rate. A few weekends ago, I charged a guy to do a total AC install into his Honda, including the vacuum/charge, replacing all o-rings, replacing every single part of the system except for the hard lines (evaporator, expansion valve, new condenser, new compressor, new drier), AND even my building custom discharge and suction hoses for him and I only charged him $500 total. Granted, I'm only a "weekend mechanic" but if $300 is fair to drop a tank then I vastly undercharged for that AC work.


Same thing for cutting open and fixing the charcoal canister. If you are unable or unwilling to do it yourself, I'd doubt you could find a shop willing to do that for you. I'm sure they'll just prefer to stick a new OEM one on there for you. If they were willing to cut open and fix your existing charcoal canister then it almost surely would cost you as much in labor charges as a new OEM one anyway.


I really think you almost might be better off finding a mechanically inclined buddy with some tools and pay him a little bit of money to do these fixes described in this thread. I never ever take my cars to shops, but I've learned over the years that a lot of shops/mechanics are either unwilling or unable (from a creativity/skill aspect) to do "custom" fixes.

 

My quick guess is that $300 to R&R a gas tank is too high. Independent shops around San Diego charge about $105/hr, and with a hoist, I can't see it taking much more than an hour. James: I'm surprised that you could buy the A/C parts for $500. Tovstyj, I doubt if you will find a mechanic to do the custom repairs you want because of legal liability. If anything happens, even if it is not the fault of the repairs, often courts will find the mechanic at least partially liable. If the mechanic follows approved methods by the manufacturer, then he's off the hook. I have found that "mobil mechanics" will do things of a custom nature, and charge less. A lot are listed on craig's list, and some are a strictly cash business. Even if you are not mechanically minded, it is fairly easy to remove the black plastic cover to the rear of the rear wheel that covers the carbon tank. Try the test at the beginning of the thread. The clamps come off with pliers. When you take a hose end off, shake it and see if any charcoal granules come out. That will help you determine if the canister is defective. Just doing small things like that is a good way to learn about cars.

 

I just checked the prices of Honda Civic A/C parts on Rock Auto and it seems that they are quite reasonable, about $460 for everything you mentioned. For my daughter's '02 Accent, it was about $500. Good Luck

 

I should clarify I didn't supply/buy the parts for that AC job, he bought all the parts. My $500 was for just my labor (it was an all day job with the custom hoses being a few hours of that), but even at that he had an entirely 100% brand new (actually upgraded) system for about $800 total. Here in Texas, you'll almost certainly get charged about $800-$1000 at a shop for JUST a compressor change with evacuation/recharge.

 

Thank you for the responses.
The previous shop charged $100 for diagnostics (including the useless "smoke" test), and wanted to drop the tank - they said it is 3 hours of work at $95/hour. Based on your replies, I think I made the right decision to decline.
Probably checking the charcoal canister myself would be a good idea, but I thought it was much more difficult (I don't know a lot about cars).
Anyway, took the car to a different, cheaper shop, explained the situation, gave the print-outs of this thread, explaining what I would like to have checked they were not too excited but took the car, worked all day today on it and said they are still checking something, hopefully there will be some news tomorrow.
When this problem appeared I really thought it was something simple (and cheap). Now I am really hoping I will lose only several hundred.

 

I hope that I didn't speak too hastily, but I have removed the gas tank from my daughter's '02 Accent, and it didn't take me very long. I was working on my back with the car on ramps, and I'm a shade-tree mechanic who is 61 and slower now. I didn't know about removing the hoses through the access hole, and I broke a fitting off of the fuel pump. That being said, there was extra time involved with learning how to fix it as I went, plus replacing the fuel pump assembly, I don't think that I spent over 5 hours on it. Pulling off the vent hoses, there was carbon everywhere. I went to a self-service wrecking yard, and pulled 6 canisters off before I found one that did not have carbon falling out of it. I installed it, and a year later, it is showing problems with venting. A new one at the dealer was $187. Looking under my other daughter's Sonata, it doesn't look all that different.

 

Seeing if charcoal is in the lines or loose anywhere is important. On some models, like my 2009 Sonata, dropping the tank is necessary to see why extreme conditions exist like not being able to fill tank with gas, constant clickoffs, etc. Let us not forget the air filter between the charcoal canister and the fill neck. Take it off, and substitute a 1/2 inch copper pipe and go see if you can fill up. If so, the air filter is dead (and expensive to replace). If it keeps clicking off, beyond the two solenoids, dropping the tank when you have little to no gas in it is going to be necessary. Others have posted here how to cut open the canister, fix it up with a gas-proof material that lets air in and keeps pellets out, and is silicon-sealed. That seems like a permanent solution. I would never change out for a new canister as they fail after so many years. I would cut, fix up, and seal, fix up with bungie cords to keep pressure on it for three days, then reinstall and blow out lines. The fuel assembly is yours to open and inspect but should be removed. A small tractor or motorcycle jack, about $99 from tool stores, will be a big help in lowering the tank and lifting it back up.

 

Stinks about it failing again a year later, but if you look back at my pics of the inner material and how I fixed it found earlier in this thread, it's very obvious why all of these fail. Hyundai just uses a very crummy foam material on them, which was a very poor decision on their part IMO. They should have used steel mesh like I did on my repair.

 

Just wanted to give an update on my problem. In the end, the second shop fixed the issue: replaced the charcoal canister ($230) and "canister close valve" ($75), cleaned lines, didn't have to take the gas tank down, 2 h labor at $96/h. Total+tax+fees=$550. So far I refueled once, everything seems to be working well.