Slow Fuel Fill Problem Diagnosis
Junior Member
Joined: Jul 2018
Posts: 3
this is my first post on this thread. i have been struggling with an 09 sonata 2.4L slow fuel fill and MIL lamp on/off issue for a number of months and miles. i spent a lot of time reading threads on this and other sites. i took the easy road and have replaced the canister vent valve, the fuel pump assembly [which includes the fuel tank pressure sensor] and now the charcoal canister [which i purchased from autozone for about $100 and has a hyundai logo on it]. unfortunately, the old canister [original as far as i know, with 106KMiles] appeared to be in perfect condition. no bits and pieces in any of the 3 attached lines, and air flows as freely though it as it does with the new replacement canister, with very little back pressure. i also removed the canister inline air vent filter, and while i can blow through it in both directions, there is substantial back pressure, but i have nothing to compare with. i plan to follow the suggestion of an earlier post and temporarily substitute a piece of 1/2" copper pipe and see what happens.
i did check the fuel tank vent line and it appears to be working as expected, allows air to exit the tank and not flow into the tank. likewise, the fuel tank filler port allows air [and hopefully fuel] to flow into the tank and not out of. the tank "recirculation" port allows air to flow into the tank [with some back pressure], but not out. i assume this the normal.
as for exchanging the canister, i was able to remove the two rear fuel tank strap attachments while supporting the tank with a jack [car up on jack stands also], and lower the rear of the tank enough to get the canister assembly out of its location above the cross member. note that i minimized the weight of the tank by using up most of the fuel. lowering the rear of the tank also gave easier access to the two canister assembly frame mounting bolts as well as the fuel fill hose clamp on the tank. the fuel fill hose had to be removed before the tank could be lowered enough for the canister assembly to exit between the tank and the cross member. having not worked with the quick-connect connectors used on various lines, it took me some time to figure out how to get my fingers around them to press the release on both sides simultaneously. another case where having the rear of the fuel tank lowered help for access.
i will put all things back together in two days, make the copper pipe substitution, and report the results here.
i did check the fuel tank vent line and it appears to be working as expected, allows air to exit the tank and not flow into the tank. likewise, the fuel tank filler port allows air [and hopefully fuel] to flow into the tank and not out of. the tank "recirculation" port allows air to flow into the tank [with some back pressure], but not out. i assume this the normal.
as for exchanging the canister, i was able to remove the two rear fuel tank strap attachments while supporting the tank with a jack [car up on jack stands also], and lower the rear of the tank enough to get the canister assembly out of its location above the cross member. note that i minimized the weight of the tank by using up most of the fuel. lowering the rear of the tank also gave easier access to the two canister assembly frame mounting bolts as well as the fuel fill hose clamp on the tank. the fuel fill hose had to be removed before the tank could be lowered enough for the canister assembly to exit between the tank and the cross member. having not worked with the quick-connect connectors used on various lines, it took me some time to figure out how to get my fingers around them to press the release on both sides simultaneously. another case where having the rear of the fuel tank lowered help for access.
i will put all things back together in two days, make the copper pipe substitution, and report the results here.
Junior Member
Joined: Aug 2014
Posts: 13
Well thank you for explaining how to lower the tank. I never figured that out. Remember, if you jack up your rear left side, take off the tire, and remove the well cover, you get to one solenoid. This is in case you have to move past the copper pipe thing (you still have trouble with filling gas). I changed mine just because of because, and the one under the hood on the slightly to the right center of the engine front. The air filter for the gas tank...you really can't blow it out and make it work for very long. So if your canister is fine, and you remove the air filter...and you are successful, great. If not, change the two solenoids to make life easier on yourself. I think Advance or Autozone has the solenoids...modestly priced. Once you reach the point of where it is easy to fill the tank, you are done. I think the solenoid(s) give(s) up the ghost too and when I did mine, I just wanted to get it working and be done. The front solenoid is easy enough to do. The one under the left wheel well cover is easy enough but a bit more of a nuisance. I have changed mine 2x is 242,000 miles. However, the dealer did two under warranty. If you have 106,000 miles on yours, count yourself lucky you did not have to change anything 50,000 miles ago.. It seems every 45-50 k the fuel fill problem comes back.
Last edited by dkodgis; Nov 22, 2018 at 09:27 AM.
Member
Joined: Jun 2013
Posts: 30
Motretu: With back pressure in the air filter I would replace it anyway, and if I were betting on it, I'd say that it is the problem. I cut mine open with a reciprocating saw and found 2 problems. The first problem is that the filter is just 4 pieces of filter paper, and the part of the filter that is exposed to the atmosphere was clogged with dust. Makes sense that it would be clogged, since it is just behind the rear tire on my 2002 Accent, and San Diego can be a dusty area. The other problem is that the filter paper exposed to the atmosphere is much smaller than the piece that is behind it, so it clogs up quickly- Stupid design!! MacGyver would be proud of my solution. Dacron fill for upholstery does not dissolve in gasoline (I tried it). It looks like raw cotton before it is spun into thread. I put some in the filter housing, glued the housing back together, and reinstalled it. We have not had any problems filling the tank for about 4 years now. If you look at much earlier posts, in Great Britain I think that it was BP that changed all of their fill nozzles on their pumps to a smaller size so that people could fill their Hyundais. Hyundais have a small diameter tube to the tank, so that when the tank is being filled, there is very little room for vapor to escape. That creates back pressure which trips the fill nozzle shut off. Sometimes there has been a problem of the incoming gasoline completely blocks off the fill tube in the car, pressure builds up in the tank, and when the fill nozzle shuts off, a lot of gasoline will blow back out of the fill pipe.
Junior Member
Joined: Jul 2018
Posts: 3
update on my post, this thread, of 11/21/2018 re 09sonata 2.4L slow fuel fill and MIL indicator.
put all parts back [did not have any left over
] with the canister air vent filter replaced by a tube. took car to local fuel station [which had issues filling in the past] and tank filled 15gals without issue, with nozzle inserted normally. so i'm inclined to believe that the canister air vent filter being partially plugged was the issue [given that the original canister, which was replaced cause i had a new one, showed no signs of failure]. have not gone the next step to replace or modify the canister vent filter. according to my partner of the last 2 yrs, who owns the car and has driven it since new, the slow fill issue has been around for at least 20k miles, but has been manageable until recently. the car has been to several repair shops for the slow fill and MIL issues, including a smog test. each time, the car has been returned with the MIL lamp off, and a pass on the smog test. but in all cases, the MIL came on with in 1k miles or so, and the slow fill issue was not corrected. the jury is still out on the MIL issue, as the indicator had gone off by itself [common behavior] before i started the current project.
clearly it would have been much easier to have done the canister air filter trick first, but i did not find this thread till recently, and i had already purchased a new canister [and did not realize the level of difficulty replacing the canister], and had already replaced the fuel cap and canister vent close valve.
put all parts back [did not have any left over
] with the canister air vent filter replaced by a tube. took car to local fuel station [which had issues filling in the past] and tank filled 15gals without issue, with nozzle inserted normally. so i'm inclined to believe that the canister air vent filter being partially plugged was the issue [given that the original canister, which was replaced cause i had a new one, showed no signs of failure]. have not gone the next step to replace or modify the canister vent filter. according to my partner of the last 2 yrs, who owns the car and has driven it since new, the slow fill issue has been around for at least 20k miles, but has been manageable until recently. the car has been to several repair shops for the slow fill and MIL issues, including a smog test. each time, the car has been returned with the MIL lamp off, and a pass on the smog test. but in all cases, the MIL came on with in 1k miles or so, and the slow fill issue was not corrected. the jury is still out on the MIL issue, as the indicator had gone off by itself [common behavior] before i started the current project.clearly it would have been much easier to have done the canister air filter trick first, but i did not find this thread till recently, and i had already purchased a new canister [and did not realize the level of difficulty replacing the canister], and had already replaced the fuel cap and canister vent close valve.
Junior Member
Joined: Jul 2018
Posts: 3
update 2 on my post, this thread, of 11/21/2018 re 09sonata 2.4L slow fuel fill and MIL indicator
hyndai calls the unit we've been referring to as a "canister filter" by a different name, "auxiliary vapor canister" pn 314210A000. a local san diego dealer sells it for $201, but i found it on amazon for $161 and ebay for $121. according to the SD dealer, the real canister vent "air filter" is integrated with the canister vent close valve and that's consistent with my searches. so it is not clear what the "auxiliary vapor canister" is intended to do. i did find a claim the the unit contains additional charcoal, but that is not consistent with what was reported in this thread..
i have not taken my unit apart yet, but one poster in this thread reported an interior series of elements that look like filters rather than charcoal elements. so i'm confused and will need to take mine apart to clarify.
hyndai calls the unit we've been referring to as a "canister filter" by a different name, "auxiliary vapor canister" pn 314210A000. a local san diego dealer sells it for $201, but i found it on amazon for $161 and ebay for $121. according to the SD dealer, the real canister vent "air filter" is integrated with the canister vent close valve and that's consistent with my searches. so it is not clear what the "auxiliary vapor canister" is intended to do. i did find a claim the the unit contains additional charcoal, but that is not consistent with what was reported in this thread..
i have not taken my unit apart yet, but one poster in this thread reported an interior series of elements that look like filters rather than charcoal elements. so i'm confused and will need to take mine apart to clarify.
Junior Member
Joined: Aug 2014
Posts: 13
Between one of the fuel fill neck hoses and the charcoal canister is a cylinder air filter. That is what I removed and used the copper pipe for. When I got under the car and removed one hose off of the cylinder air filter, and the other end of a hose also connected to the charcoal canister, the result was there were two rubber hoses coming off of the charcoal canister...so I could see a) if there were charcoal pellets showing up out of the hoses when I freed up the hose ends , and b) if air was flowing through one hose end it when I blew on the other end of the hose. In my case, I saw no pellets and I saw none exit the charcoal canister when blowing through either hose so I thought my charcoal canister was fine. I did not want to drop it and change it and until a few posts ago when someone said to lower the tank, I did not even know how to change it.
I concentrated on changing the fuel tank fill neck solenoid. If memory serves, that was about $24. The other solenoid under the hood was a bit more but I did both in case the back pressure had somehow damaged them. I was not going to test them with a meter to see if voltage was there and I could not find specs. So for me, the two solenoids and the substitution of the 1/2 inch size and six inches in length copper pipe worked in place of the gas tank air filter in the form of a cylinder. Everything was fairly easy.
Of course if you suspect your charcoal canister and/or if you see charcoal pellets, then change it. The only air filter for the gas tank is the cylinder-shaped one in-line between one of the hoses coming off the filler neck and going to the air filter cylinder, and coming out of the air filter and over to one of the ports on the charcoal canister. Everything is easy enough to do except the charcoal canister.
As an aside, when I had the car from new until 46,000 miles, the fuel thing kicked in. I took it to the dealer, and they fixed it (changed the two solenoids, and air filter cylinder). However, in a week the light came back on. I took it back to the dealer and they changed the charcoal canister. I have to think they thought it was OK because of no loose pellets but in that case, I guess it was not. I still have the same charcoal canister 200,000 miles later. What drove me to simple? The last two times, I never knew how to change the charcoal canister and the dealer would not tell me. However, the two times I changed the solenoids and the second time I took out the air filter cylinder after 190,000 miles, all worked. One other tip, if you are not in a hurry, is to leave the two hoses connected to the charcoal canister and loose/not connected on the other end for a day or two so vapor escapes (obviously, do not drive the car unless everything is back, connected). If you really need to change the charcoal canister, and the solenoids, and the air filter, it turns into a pretty penny. So I kept my charcoal canister which all indications pointed to its working, and ditched the air filter cylinder for the gas tank, and did the easy, less expensive solenoids. The charcoal canister would have been the only thing left. So I did not have to bite the bullet and go for the canister.
At each step, but with everything reconnected, have a small gas can ready to try to fill the tank. If the gas goes in easy, you are done. If not, you have to continue and decide what steps you want to tackle or need to tackle where there is obvious physical damage. I tried to blow out the air cylinder filter for five days with a monster compressor. It worked for a day or two and the light came on. In other words, the air filter needs to be replaced or removed. It saves money and my car has passed inspection every time. In all, I have had the fuel thing four times. Dealer=one fix. Me=three fixes. If I had to swap out the air and charcoal things, it would be a hit on the wallet. First I work simple until I have to open my wallet. Hyundai knows this fuel thing happens. I guess it is a money maker for them
I concentrated on changing the fuel tank fill neck solenoid. If memory serves, that was about $24. The other solenoid under the hood was a bit more but I did both in case the back pressure had somehow damaged them. I was not going to test them with a meter to see if voltage was there and I could not find specs. So for me, the two solenoids and the substitution of the 1/2 inch size and six inches in length copper pipe worked in place of the gas tank air filter in the form of a cylinder. Everything was fairly easy.
Of course if you suspect your charcoal canister and/or if you see charcoal pellets, then change it. The only air filter for the gas tank is the cylinder-shaped one in-line between one of the hoses coming off the filler neck and going to the air filter cylinder, and coming out of the air filter and over to one of the ports on the charcoal canister. Everything is easy enough to do except the charcoal canister.
As an aside, when I had the car from new until 46,000 miles, the fuel thing kicked in. I took it to the dealer, and they fixed it (changed the two solenoids, and air filter cylinder). However, in a week the light came back on. I took it back to the dealer and they changed the charcoal canister. I have to think they thought it was OK because of no loose pellets but in that case, I guess it was not. I still have the same charcoal canister 200,000 miles later. What drove me to simple? The last two times, I never knew how to change the charcoal canister and the dealer would not tell me. However, the two times I changed the solenoids and the second time I took out the air filter cylinder after 190,000 miles, all worked. One other tip, if you are not in a hurry, is to leave the two hoses connected to the charcoal canister and loose/not connected on the other end for a day or two so vapor escapes (obviously, do not drive the car unless everything is back, connected). If you really need to change the charcoal canister, and the solenoids, and the air filter, it turns into a pretty penny. So I kept my charcoal canister which all indications pointed to its working, and ditched the air filter cylinder for the gas tank, and did the easy, less expensive solenoids. The charcoal canister would have been the only thing left. So I did not have to bite the bullet and go for the canister.
At each step, but with everything reconnected, have a small gas can ready to try to fill the tank. If the gas goes in easy, you are done. If not, you have to continue and decide what steps you want to tackle or need to tackle where there is obvious physical damage. I tried to blow out the air cylinder filter for five days with a monster compressor. It worked for a day or two and the light came on. In other words, the air filter needs to be replaced or removed. It saves money and my car has passed inspection every time. In all, I have had the fuel thing four times. Dealer=one fix. Me=three fixes. If I had to swap out the air and charcoal things, it would be a hit on the wallet. First I work simple until I have to open my wallet. Hyundai knows this fuel thing happens. I guess it is a money maker for them
Last edited by dkodgis; Nov 24, 2018 at 07:39 AM.
Junior Member
Joined: Nov 2019
Posts: 1
Thanks!
Not sure if you're still on here as this was clearly from a while ago - but gotta say thanks for the great write-up and diagrams/pics! Went ahead and fixed this on my daughters "new to her" 2004 sonata this weekend. She's only had the car for about 2.5 months, but failed to inform me that the gas fill has always been 'difficult' or slow...until I took it to repair 2 other issues - cam & crankshaft position sensors - and put some gas in it and what like WTH?? LOL
Did the cut the access hole deal, but did it with a dremel & cutting wheel ;-) I'm a racer so I have tons of tools...
I'm replacing the canister with supposedly a "better/new" aftermarket part instead of modifying the original though, time better spent doing other things imo, although if I ever have to do this again I have the old one to hack on! :-)
Did the cut the access hole deal, but did it with a dremel & cutting wheel ;-) I'm a racer so I have tons of tools...
I'm replacing the canister with supposedly a "better/new" aftermarket part instead of modifying the original though, time better spent doing other things imo, although if I ever have to do this again I have the old one to hack on! :-)
Fixing the “hard to fill gas tank” problem, without removing the gas tank. Sonata 2004, 2.4L 4cyl. Like so many others I too had the slow fill problem. I fixed the carbon canister and then the air-filter and still no joy. I removed the gas tank, pulled the “Fill Vent Valve (ORVR )” and shook out the carbon pellets and that was the problem. Back together and all is well. I will tell you that pulling the gas tank is a pain and was unnecessary. I came up with a way to avoid pulling the tank. First a review of what others have done and my own work. Note my info about the carbon canister is specific to the Sonata. It seems there are different canisters for different models and my info on the canister is Sonata specific.
Diagnosis: Slow fill. If when you first begin filling gas, you can get 1 or 2 tenths gal in before the cutoff it is UN-likely to be a stuck “Fuel Shutoff Valve” or the head of a Barbie doll stuck down the filler pipe. Also if the slow fill problem has been getting progressively worse over time this is a clear indication that the foam filters in the carbon canister have failed and now little carbon pellets are floating through the hoses where they ought not be. And the chances are near 100% they have clogged up the “Fill Vent Valve (ORVR )” and that is the primary issue as to why you can't fill the car with fuel.
1. Pull the Carbon canister. I marked the ˝ inch ID hose going to the Canister Close Valve with a white marker so as to make reassembly easier. Same for the small hose going to the fuel tank pressure sensor. And a corresponding mark on the canister. If carbon pellets fall out when you pull the hoses off or when you shake the canister with the tubes down, then you know for sure the canister is defective. Get a new one. In my opinion all of them made from 96-05 are defective so buying one at a junk yard is begging for more trouble. Or if you want to repair yours I suggest cutting off the rear end without the 4 ports about an inch from the end. I emptied mine out and replaced the foam goo with green scrub pads that I had on hand. Would have used the white if I had it. Local supermarket item. Two 6x9 inch pads will work fine. By cutting an inch from the end you can use some thin strips of metal (I used Aluminum) 1x5 and pop riveted it back together. Then sealed it with a hot glue gun. It must be air tight. Any air leaks and the check engine light will come on. Just buy a canister unless you always wanted to know what was in there. Don't put it back on yet.
2. The “Fill Vent Valve (ORVR )” has carbon pellets in it and that is what is keeping you from filling the tank. While this is called a “Fill Vent Valve” it also has a float that sticks down in the tank about 6 inches and in normal operation when the tank fills, the float pushes up and cuts off the outgoing air. There is a large (1 cm) ball bearing in the top of the valve that pushes down and holds the air vent open. But when the float pushes up from the bottom and carbon pellets are present they hold the ball bearing up and that keeps the valve closed all the time. So you start fueling with the “Fill Vent Valve” already closed and of course it shuts you down. When I pulled my “Fill Vent Valve” out and shook it the ball rattled and a bunch of pellets fell out. Then when I disassembled it it was clean and had no problems. I mention this because it shows that it is easy to clean without dis-assembly. BTW there is no reason to buy one of these. They are easy to clean and have no parts other than the gasket that can go bad. My gasket was in excellent condition and was reused.
Update: There is also a small spring in the valve that holds the valve up (closed) if tilted on it's side or upside down. The weight (force) of the ball bearing is greater than the spring and opens the valve when the tank is not full. See the Fig 4 below to see how the carbon pellets fall under the ball bearing and keep it from pushing down and opening the valve.
Attachment 1209
3. I had considered using a vacuum to try and suck the carbon out but after thinking on it a bit I decided the ball bearing resting on the carbon would not allow the pellets to come out. That leaves two solutions. Remove the tank or make an access panel to get at the “Fill Vent Valve”. Please understand that there is already a plastic access panel to get to the fuel pump. It is in the center of the car at the back of the trunk. Open that up and you'll see the fuel tank is about 1.5 inches below the access panel.
The “Fill Vent Valve” is 7 inches to the left side of the fuel pump on the Sonata. Measure from the left side of the fuel pump 5 and 9 inches to the left and mark (Sharpie). You now have two marks 4 inches apart left of the fuel pump and on center line of the fuel pump. Drill 1/4 inch holes at those marks. Warning. Just drill through the trunk and not the gas tank
SPECIAL TOOL NEEDED. Harbor Freight Tools sheet metal nibbler. They sell 2. One is up to 22 gauge and the other is up to 18 gauge. The smaller number is thicker so get it. SKU 60507 under ten dollars.
With the nibbler cut between the holes and then cut forward 3 inches on each side and bend it up. Warning, sharp edges. Cover all edges with Duct-tape. The valve will be right there and you can remove it with a Phillips screwdriver (3 screws) pliers for the hose. Pull the valve out and shake it and see the pellets come out. Get an air blower and blow air through the hose in case any pesky pellets are sitting in the lines.. Put it all together and place a six inch square of sheet metal over your new access panel. Glue and screw or what ever makes you happy.
See the photos
Miscellaneous: The diagrams show an “air filter” after the canister-close-valve but don't show where it is located. It is on the side of the fuel filler tube and the liquid vapor separator just below the fuel inlet. To get to it remove the left rear wheel and then remove the plastic cover in the wheel well. The air filter is cheap and hard to cut open and repair. I'll include some pictures. Newer cars call for replacing it every 60k miles. Probably a good idea to replace it if you are doing everything else. Mine was very dirty and had a little resistance to air flow. Once you get to it there are three bolts holding it in (10mm heads).
“Fill Vent Valve” can be disassembled by prying the two tabs (under the gasket). If the tabs break it is not a problem as the three screws hold every thing in place. Don't leave the ball bearing out or you cant fill the tank.
Attachment 1202
Attachment 1203
Attachment 1204
Attachment 1205
Diagnosis: Slow fill. If when you first begin filling gas, you can get 1 or 2 tenths gal in before the cutoff it is UN-likely to be a stuck “Fuel Shutoff Valve” or the head of a Barbie doll stuck down the filler pipe. Also if the slow fill problem has been getting progressively worse over time this is a clear indication that the foam filters in the carbon canister have failed and now little carbon pellets are floating through the hoses where they ought not be. And the chances are near 100% they have clogged up the “Fill Vent Valve (ORVR )” and that is the primary issue as to why you can't fill the car with fuel.
1. Pull the Carbon canister. I marked the ˝ inch ID hose going to the Canister Close Valve with a white marker so as to make reassembly easier. Same for the small hose going to the fuel tank pressure sensor. And a corresponding mark on the canister. If carbon pellets fall out when you pull the hoses off or when you shake the canister with the tubes down, then you know for sure the canister is defective. Get a new one. In my opinion all of them made from 96-05 are defective so buying one at a junk yard is begging for more trouble. Or if you want to repair yours I suggest cutting off the rear end without the 4 ports about an inch from the end. I emptied mine out and replaced the foam goo with green scrub pads that I had on hand. Would have used the white if I had it. Local supermarket item. Two 6x9 inch pads will work fine. By cutting an inch from the end you can use some thin strips of metal (I used Aluminum) 1x5 and pop riveted it back together. Then sealed it with a hot glue gun. It must be air tight. Any air leaks and the check engine light will come on. Just buy a canister unless you always wanted to know what was in there. Don't put it back on yet.
2. The “Fill Vent Valve (ORVR )” has carbon pellets in it and that is what is keeping you from filling the tank. While this is called a “Fill Vent Valve” it also has a float that sticks down in the tank about 6 inches and in normal operation when the tank fills, the float pushes up and cuts off the outgoing air. There is a large (1 cm) ball bearing in the top of the valve that pushes down and holds the air vent open. But when the float pushes up from the bottom and carbon pellets are present they hold the ball bearing up and that keeps the valve closed all the time. So you start fueling with the “Fill Vent Valve” already closed and of course it shuts you down. When I pulled my “Fill Vent Valve” out and shook it the ball rattled and a bunch of pellets fell out. Then when I disassembled it it was clean and had no problems. I mention this because it shows that it is easy to clean without dis-assembly. BTW there is no reason to buy one of these. They are easy to clean and have no parts other than the gasket that can go bad. My gasket was in excellent condition and was reused.
Update: There is also a small spring in the valve that holds the valve up (closed) if tilted on it's side or upside down. The weight (force) of the ball bearing is greater than the spring and opens the valve when the tank is not full. See the Fig 4 below to see how the carbon pellets fall under the ball bearing and keep it from pushing down and opening the valve.
Attachment 1209
3. I had considered using a vacuum to try and suck the carbon out but after thinking on it a bit I decided the ball bearing resting on the carbon would not allow the pellets to come out. That leaves two solutions. Remove the tank or make an access panel to get at the “Fill Vent Valve”. Please understand that there is already a plastic access panel to get to the fuel pump. It is in the center of the car at the back of the trunk. Open that up and you'll see the fuel tank is about 1.5 inches below the access panel.
The “Fill Vent Valve” is 7 inches to the left side of the fuel pump on the Sonata. Measure from the left side of the fuel pump 5 and 9 inches to the left and mark (Sharpie). You now have two marks 4 inches apart left of the fuel pump and on center line of the fuel pump. Drill 1/4 inch holes at those marks. Warning. Just drill through the trunk and not the gas tank
SPECIAL TOOL NEEDED. Harbor Freight Tools sheet metal nibbler. They sell 2. One is up to 22 gauge and the other is up to 18 gauge. The smaller number is thicker so get it. SKU 60507 under ten dollars.
With the nibbler cut between the holes and then cut forward 3 inches on each side and bend it up. Warning, sharp edges. Cover all edges with Duct-tape. The valve will be right there and you can remove it with a Phillips screwdriver (3 screws) pliers for the hose. Pull the valve out and shake it and see the pellets come out. Get an air blower and blow air through the hose in case any pesky pellets are sitting in the lines.. Put it all together and place a six inch square of sheet metal over your new access panel. Glue and screw or what ever makes you happy.
See the photos
Miscellaneous: The diagrams show an “air filter” after the canister-close-valve but don't show where it is located. It is on the side of the fuel filler tube and the liquid vapor separator just below the fuel inlet. To get to it remove the left rear wheel and then remove the plastic cover in the wheel well. The air filter is cheap and hard to cut open and repair. I'll include some pictures. Newer cars call for replacing it every 60k miles. Probably a good idea to replace it if you are doing everything else. Mine was very dirty and had a little resistance to air flow. Once you get to it there are three bolts holding it in (10mm heads).
“Fill Vent Valve” can be disassembled by prying the two tabs (under the gasket). If the tabs break it is not a problem as the three screws hold every thing in place. Don't leave the ball bearing out or you cant fill the tank.
Attachment 1202
Attachment 1203
Attachment 1204
Attachment 1205
Junior Member
Joined: Sep 2020
Posts: 1
Thank you!
Fixing the “hard to fill gas tank” problem, without removing the gas tank. Sonata 2004, 2.4L 4cyl. Like so many others I too had the slow fill problem. I fixed the carbon canister and then the air-filter and still no joy. I removed the gas tank, pulled the “Fill Vent Valve (ORVR )” and shook out the carbon pellets and that was the problem. Back together and all is well. I will tell you that pulling the gas tank is a pain and was unnecessary. I came up with a way to avoid pulling the tank. First a review of what others have done and my own work. Note my info about the carbon canister is specific to the Sonata. It seems there are different canisters for different models and my info on the canister is Sonata specific.
Diagnosis: Slow fill. If when you first begin filling gas, you can get 1 or 2 tenths gal in before the cutoff it is UN-likely to be a stuck “Fuel Shutoff Valve” or the head of a Barbie doll stuck down the filler pipe. Also if the slow fill problem has been getting progressively worse over time this is a clear indication that the foam filters in the carbon canister have failed and now little carbon pellets are floating through the hoses where they ought not be. And the chances are near 100% they have clogged up the “Fill Vent Valve (ORVR )” and that is the primary issue as to why you can't fill the car with fuel.
1. Pull the Carbon canister. I marked the ˝ inch ID hose going to the Canister Close Valve with a white marker so as to make reassembly easier. Same for the small hose going to the fuel tank pressure sensor. And a corresponding mark on the canister. If carbon pellets fall out when you pull the hoses off or when you shake the canister with the tubes down, then you know for sure the canister is defective. Get a new one. In my opinion all of them made from 96-05 are defective so buying one at a junk yard is begging for more trouble. Or if you want to repair yours I suggest cutting off the rear end without the 4 ports about an inch from the end. I emptied mine out and replaced the foam goo with green scrub pads that I had on hand. Would have used the white if I had it. Local supermarket item. Two 6x9 inch pads will work fine. By cutting an inch from the end you can use some thin strips of metal (I used Aluminum) 1x5 and pop riveted it back together. Then sealed it with a hot glue gun. It must be air tight. Any air leaks and the check engine light will come on. Just buy a canister unless you always wanted to know what was in there. Don't put it back on yet.
2. The “Fill Vent Valve (ORVR )” has carbon pellets in it and that is what is keeping you from filling the tank. While this is called a “Fill Vent Valve” it also has a float that sticks down in the tank about 6 inches and in normal operation when the tank fills, the float pushes up and cuts off the outgoing air. There is a large (1 cm) ball bearing in the top of the valve that pushes down and holds the air vent open. But when the float pushes up from the bottom and carbon pellets are present they hold the ball bearing up and that keeps the valve closed all the time. So you start fueling with the “Fill Vent Valve” already closed and of course it shuts you down. When I pulled my “Fill Vent Valve” out and shook it the ball rattled and a bunch of pellets fell out. Then when I disassembled it it was clean and had no problems. I mention this because it shows that it is easy to clean without dis-assembly. BTW there is no reason to buy one of these. They are easy to clean and have no parts other than the gasket that can go bad. My gasket was in excellent condition and was reused.
Update: There is also a small spring in the valve that holds the valve up (closed) if tilted on it's side or upside down. The weight (force) of the ball bearing is greater than the spring and opens the valve when the tank is not full. See the Fig 4 below to see how the carbon pellets fall under the ball bearing and keep it from pushing down and opening the valve.
Attachment 1209
3. I had considered using a vacuum to try and suck the carbon out but after thinking on it a bit I decided the ball bearing resting on the carbon would not allow the pellets to come out. That leaves two solutions. Remove the tank or make an access panel to get at the “Fill Vent Valve”. Please understand that there is already a plastic access panel to get to the fuel pump. It is in the center of the car at the back of the trunk. Open that up and you'll see the fuel tank is about 1.5 inches below the access panel.
The “Fill Vent Valve” is 7 inches to the left side of the fuel pump on the Sonata. Measure from the left side of the fuel pump 5 and 9 inches to the left and mark (Sharpie). You now have two marks 4 inches apart left of the fuel pump and on center line of the fuel pump. Drill 1/4 inch holes at those marks. Warning. Just drill through the trunk and not the gas tank
SPECIAL TOOL NEEDED. Harbor Freight Tools sheet metal nibbler. They sell 2. One is up to 22 gauge and the other is up to 18 gauge. The smaller number is thicker so get it. SKU 60507 under ten dollars.
With the nibbler cut between the holes and then cut forward 3 inches on each side and bend it up. Warning, sharp edges. Cover all edges with Duct-tape. The valve will be right there and you can remove it with a Phillips screwdriver (3 screws) pliers for the hose. Pull the valve out and shake it and see the pellets come out. Get an air blower and blow air through the hose in case any pesky pellets are sitting in the lines.. Put it all together and place a six inch square of sheet metal over your new access panel. Glue and screw or what ever makes you happy.
See the photos
Miscellaneous: The diagrams show an “air filter” after the canister-close-valve but don't show where it is located. It is on the side of the fuel filler tube and the liquid vapor separator just below the fuel inlet. To get to it remove the left rear wheel and then remove the plastic cover in the wheel well. The air filter is cheap and hard to cut open and repair. I'll include some pictures. Newer cars call for replacing it every 60k miles. Probably a good idea to replace it if you are doing everything else. Mine was very dirty and had a little resistance to air flow. Once you get to it there are three bolts holding it in (10mm heads).
“Fill Vent Valve” can be disassembled by prying the two tabs (under the gasket). If the tabs break it is not a problem as the three screws hold every thing in place. Don't leave the ball bearing out or you cant fill the tank.
Attachment 1202
Attachment 1203
Attachment 1204
Attachment 1205
Diagnosis: Slow fill. If when you first begin filling gas, you can get 1 or 2 tenths gal in before the cutoff it is UN-likely to be a stuck “Fuel Shutoff Valve” or the head of a Barbie doll stuck down the filler pipe. Also if the slow fill problem has been getting progressively worse over time this is a clear indication that the foam filters in the carbon canister have failed and now little carbon pellets are floating through the hoses where they ought not be. And the chances are near 100% they have clogged up the “Fill Vent Valve (ORVR )” and that is the primary issue as to why you can't fill the car with fuel.
1. Pull the Carbon canister. I marked the ˝ inch ID hose going to the Canister Close Valve with a white marker so as to make reassembly easier. Same for the small hose going to the fuel tank pressure sensor. And a corresponding mark on the canister. If carbon pellets fall out when you pull the hoses off or when you shake the canister with the tubes down, then you know for sure the canister is defective. Get a new one. In my opinion all of them made from 96-05 are defective so buying one at a junk yard is begging for more trouble. Or if you want to repair yours I suggest cutting off the rear end without the 4 ports about an inch from the end. I emptied mine out and replaced the foam goo with green scrub pads that I had on hand. Would have used the white if I had it. Local supermarket item. Two 6x9 inch pads will work fine. By cutting an inch from the end you can use some thin strips of metal (I used Aluminum) 1x5 and pop riveted it back together. Then sealed it with a hot glue gun. It must be air tight. Any air leaks and the check engine light will come on. Just buy a canister unless you always wanted to know what was in there. Don't put it back on yet.
2. The “Fill Vent Valve (ORVR )” has carbon pellets in it and that is what is keeping you from filling the tank. While this is called a “Fill Vent Valve” it also has a float that sticks down in the tank about 6 inches and in normal operation when the tank fills, the float pushes up and cuts off the outgoing air. There is a large (1 cm) ball bearing in the top of the valve that pushes down and holds the air vent open. But when the float pushes up from the bottom and carbon pellets are present they hold the ball bearing up and that keeps the valve closed all the time. So you start fueling with the “Fill Vent Valve” already closed and of course it shuts you down. When I pulled my “Fill Vent Valve” out and shook it the ball rattled and a bunch of pellets fell out. Then when I disassembled it it was clean and had no problems. I mention this because it shows that it is easy to clean without dis-assembly. BTW there is no reason to buy one of these. They are easy to clean and have no parts other than the gasket that can go bad. My gasket was in excellent condition and was reused.
Update: There is also a small spring in the valve that holds the valve up (closed) if tilted on it's side or upside down. The weight (force) of the ball bearing is greater than the spring and opens the valve when the tank is not full. See the Fig 4 below to see how the carbon pellets fall under the ball bearing and keep it from pushing down and opening the valve.
Attachment 1209
3. I had considered using a vacuum to try and suck the carbon out but after thinking on it a bit I decided the ball bearing resting on the carbon would not allow the pellets to come out. That leaves two solutions. Remove the tank or make an access panel to get at the “Fill Vent Valve”. Please understand that there is already a plastic access panel to get to the fuel pump. It is in the center of the car at the back of the trunk. Open that up and you'll see the fuel tank is about 1.5 inches below the access panel.
The “Fill Vent Valve” is 7 inches to the left side of the fuel pump on the Sonata. Measure from the left side of the fuel pump 5 and 9 inches to the left and mark (Sharpie). You now have two marks 4 inches apart left of the fuel pump and on center line of the fuel pump. Drill 1/4 inch holes at those marks. Warning. Just drill through the trunk and not the gas tank
SPECIAL TOOL NEEDED. Harbor Freight Tools sheet metal nibbler. They sell 2. One is up to 22 gauge and the other is up to 18 gauge. The smaller number is thicker so get it. SKU 60507 under ten dollars.
With the nibbler cut between the holes and then cut forward 3 inches on each side and bend it up. Warning, sharp edges. Cover all edges with Duct-tape. The valve will be right there and you can remove it with a Phillips screwdriver (3 screws) pliers for the hose. Pull the valve out and shake it and see the pellets come out. Get an air blower and blow air through the hose in case any pesky pellets are sitting in the lines.. Put it all together and place a six inch square of sheet metal over your new access panel. Glue and screw or what ever makes you happy.
See the photos
Miscellaneous: The diagrams show an “air filter” after the canister-close-valve but don't show where it is located. It is on the side of the fuel filler tube and the liquid vapor separator just below the fuel inlet. To get to it remove the left rear wheel and then remove the plastic cover in the wheel well. The air filter is cheap and hard to cut open and repair. I'll include some pictures. Newer cars call for replacing it every 60k miles. Probably a good idea to replace it if you are doing everything else. Mine was very dirty and had a little resistance to air flow. Once you get to it there are three bolts holding it in (10mm heads).
“Fill Vent Valve” can be disassembled by prying the two tabs (under the gasket). If the tabs break it is not a problem as the three screws hold every thing in place. Don't leave the ball bearing out or you cant fill the tank.
Attachment 1202
Attachment 1203
Attachment 1204
Attachment 1205
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Joined: Dec 2017
Posts: 2
Evaporator canister
Hello, I have a 2011 Hyundai Santa Fe six-cylinder I'm having a problem finding a reasonably priced evaporator canister. Part number 31420-U000 the prices I'm getting are anywhere from 500 to 875 I would like to know if anybody out there I can get a reasonable price..