5 trips to mechanics 3 times to dealer for "check engine light", which means something is wrong with fuel system. I got fed up and called hyundai customer service and after a few weeks of providing information they told me I was topping off my gas tank and causing fuel to run into a black box that is used to trap fuel vapors since the fuel system is now sealed. I was glad to find out after 30 years of driving and owning vehicles and knowing hundreds of others that finally someone told me how to fill a gas tank properly. Which if you did not get my sarcasm is a load of crap! There fuel system is faulty the cut valves and so forth work intermittently and it causes fuel to go into the black box and once that happens the light comes on. I was pleased with the hyundai product but that has come to a crashing ending, I will never buy one again. Especially when some imbecile tells me the reason I have had to bring the vehicle in 5 times in 15 months and spend over $1,000 dollars is because I can't fill a gas tank properly. If you all are having problems with any part of the fuel system don't believe its spiders or any other crap they try and tell you. I can get this type of poor performance from the big three i went with the korean option for a supposed quality car and a sturdy warranty. They told me since I was so stupid to over fill the gas tank repeatedly that the warranty would not cover it. I don't much care for any reply telling me something different. I am just giving you all a warning that there is aproblem with Hyundai and it is an expensive one since the cars will fail emissions with the system as it is.

 

The check engine light means there is a problem but it could be in many places besides the fuel system. You must get the code read first to find out what the problem is. Did you get the code?

Sorry but you are wrong. What the dealer told you is 100% correct. Modern fuel systems are very different than those from 30 years ago. They are setup in such a way thatfuel can get into the charcoal canister. Read your owners manual and it will specifically warn you about that.


Again, sorry but are not filling your tank correctly. Read your owners manual.

Sorry but there is NOT a problem with Hyundai. The problem is you. You need to read the owners manual and follow the directions correctly. Failing to do so will void your warranty. Cars are not the same today as they were year ago.

 

Educate yourself to why you shouldn't "top-off" your tank:
http://www.mercurynews.com/weekenddrive/ci_11272338
http://ask.cars.com/2007/07/gas-top-off.html
http://cartalk.com/content/eco/tips.html#3

 

Thank you for the detailed information regarding my fuel system problem. I understand the complexity of fuel system has changed drastically in the past years. I would ask "if I don't top my tank off" what would your answer be? The last service the vehicle was worked on and released to me and I drove it 8 more miles and did not add any gas and the light came back on. I took it back in the next morning and was told now the "cut valve" was not reading any current, although the day before it did. I don't top off my tank and will wait for any and all other reason why I need 5 services in 15 months all on the fuel system. Could it just be that this particular system is not functioning properly, that is breaking down before it should, that maybe something is wrong and it is a lemon for this particular car? I bought the product from them and expect more ofa response than "I don't know how to pump gas" and if all customers are so aggregiously pumping their hyundai's full of gas and overflowing the tanks into the vapor cannister, then why did everyone in that shop I ask tell me they have never heard of such trouble?

 

What was the code that caused the CEL to go on? You still haven't told us that. The code will tell you what the problem is.

Maybe because most owners actually read the owners manual and pump properly.

 

There are numerous complaints of Hyundai vehicles being hard/slow to fill with fuel. The general indication is that when refueling, the gas pump shuts off repetitively after only adding a minor volume of gas – usually ¼ gallon or less. The fuel seems to back up into the fill tube, causing the automatic shut off on the pump to activate. The fuel gradually subsides in the filler neck, and another ¼ gallon or so can be added before shutting off again.

There are two general possibilities which would cause the issue: (a) a restriction directly preventing fuel from entering the tank, or (b) a restriction preventing vapors from exiting the tank and thus not allow fuel to enter. All cars built from 1999 onward have had included an onboard fueling vapor recovery system. What this means in a nutshell is that fumes from the entire fuel system are no longer vented to the outdoors, but are instead re-cycled through the vehicle air intake system.

(a) Those things that can directly restrict fuel fill include damage to any part of the filler neck or gas tank:
1. Damaged filler neck
2. Pinched or twisted hose between filler neck and tank
3. One-way fill valve in tank (at the filler entrance to the tank) sticking shut
4. Tank damaged under fill entrance to tank.

(b) Things that can prevent proper venting include blockages anywhere in the onboard vapor recovery system:
1. Blocked leak detection pump outlet
2. Restricted charcoal canister filter
3. Restricted charcoal canister itself (usually by liquid fuel in canister)
4. Sticking vent valve (sometimes called rollover valve) in top of fuel tank
5. Any of the vapor hoses from the tank to the canister to the leak detection pump pinched or twisted.

One of the most common causes of blockage in the venting system is from fuel entering the vapor vent lines and directly into the charcoal canister. The liquid gasoline gets absorbed by the charcoal in the canister, causing it to swell and it blocks off the vapor vent lines. So how does a clogged canister filter prevent you from filling up with gas? The gas tank contains both fuel and air. As you fill it up, the gasoline displaces the air, and the air has to escape somehow. BUT the air that is displaced is full of gasoline vapor. Being harmful to the atmosphere, it can't just be vented directly into the air, so the vapor recovery system is set up to capture these vapors through a series of vent lines that lead to a square box full of charcoal, which absorbs the gas vapors. When the gas-soaked charcoal swells and blocks off the vent lines, it is preventing the air from escaping the tank. In order to put gas in, the air has to have some way of getting out, and the only way for it to get out is through the vent lines. The repair here involves replacing one of the components in the fuel vapor recovery system. (one-way valve in the tank, vent valve in the tank, liquid-vapor separator near the tank, carbon canister or canister close valve.) The most common first choice for repair is the canister, but the other components may well be plugged.

1. Canister close valve could be clogged with charcoal or not working
2. Canister filter may need replacement
3. Electrical connection to the close valve may be broken
4. Canister may be damaged
5. Purge valve from the canister may be clogged
6. Vent hoses may be clogged

The only real solution is a thorough step-by-step trouble shooting approach as described below.

General diagnostic procedures: hard-to-fill fuel tank

All 1999 and later Hyundai vehicles incorporate an emission control system known as On-Board Refueling Vapor Recovery (ORVR). A general schematic of the system is provided below. Some owners may experience difficulty filling their vehicle with gasoline and a premature shut off condition. Following are trouble shooting steps to be taken.

Step 1- Isolate which half of the system is blocked: Verify that the 1/2" vapor path from the fill vent valve on the gas tank to the air filter on the charcoal canister (see schematic below) is completely free and clear. Make sure the fuel tank is below 1/4 tank full. Disconnect the hose connected to the canister side of the liquid-vapor separator (see schematic below). Take the vehicle to a known "good" or major brand gas station. If the vehicle readily accepts fuel, the restriction is located between the liquid vapor separator and the air filter. If the vehicle does not easily accept fuel, the restriction is located between the liquid vapor separator and the fuel tank.

On-Board Refueling Vapor Recovery (ORVR) Schematic: The following components are contained in the ORVR system: Fuel Cut Valve, Fuel Fill Vent Valve, (anti-spit back), Liquid-Vapor Separator, Charcoal Canister, Canister Close Valve, Air Filter all connected by various hoses and pipes. 1999 Sonata and Accent have additional components as shown.

Step 2: After the restriction has been isolated to either half of the system, inspect each component to make sure it is free and clear of any restrictions Do this by verifying that no back pressure can be felt anywhere between the fill vent valve and the air filter at the canister.

If the tank filled easily when disconnecting the vapor hose to the canister (meaning the blockage is in the canister or close valve), inspect the canister and replace the filter if needed, and the canister if broken. Replace the canister close valve if clogged Check by blowing with lung pressure. The Charcoal Canister filter is located with the canister at the left rear corner of the vehicle. You'll need to remove one or two 12mm bolts/nuts to lower the canister assembly. You'll then need to separate the canister close valve from the filter and snap it off the canister.

If the tank does not fill easily when the canister is disconnected, the blockage is between the tank and the canister.

First check for obvious problems that would prevent fuel from entering the gas tank:

1. Damaged filler neck
2. Pinched or twisted hose between filler neck and tank
3. Tank damaged under fill entrance to tank.

Then check for kinked hoses in the vent lines, that can cause backpressure.

Then check for restrictions in the liquid vapor separator, by blowing through one end of the pipe using lung power. NO back pressure should be felt.

Then, verify that the Fill Vent Valve is open by carefully removing the valve and confirming that the white plastic shut-off plunger moves freely inside its cage. This valve is accessed from the top of the gas tank.

Then check the Fuel cut valve for restrictions. This is also accessed from the top of the fuel tank. If the fuel cut valve plunger is stuck closed, a hard-to-fill condition may result. Verify that the plunger moves up and down freely allowing fuel to enter the tank, but does not allow fuel to travel up the neck (under pressure). The plunger should be "up" (closed) in its free state.

IMPORTANT When working with the Fill Vent Valve and associated plumbing, be sure to replace the hoses into the proper hose clips to prevent fuel from getting trapped / puddled in the vapor hose. Return fuel from the liquid-vapor separator must have a clear path to drain back to the tank.

Special Notes:

(a) 1999 Sonatas have a Four Way Valve located between the liquid vapor separator and fuel tank.. The Four Way Valve provides an additional vapor path to the canister during refueling.

Proper operation of the valve is as follows: Air flows freely in either direction through the 1/2" ports. Air flows freely in either direction through the 1/4" ports. Air flows from 1/2" port to the 1/4" port when blowing into one of the 1/2" ports while plugging the other 1/2" port. Air does not flow from 1/4" port to the 1/2" port when blowing into one of the 1/4" ports while plugging the other 1/4" port

(b) Also NOTE that 1999 Accents have two (2) liquid vapor separators: one located on top of the fuel tank, the other located alongside the filler neck.

(c) Also note that one owner had a novel, no-cost solution. You can give it a try before investing in the long-term solution. Here is his feedback: “I have the same type of quirkiness on my 01' Elantra. My fix was to fill up when the gas needle is at the half way mark rather then when it's on empty. I was told by an attendant that fumes can build up in the tank and the pressure can cause the gas nozzle to pop out. I was guilty of driving around on near empty then only filling up but since I started filling up it up when the needle is at the half way mark the problem went away. You may have to do this a couple of times before the problem goes away.”