When tank is below 1/2 full the car is hard to start and when driving it seems to lose power. My check engine light does not come on.

SOURCE: fill up with gas

i had the same problem, you have to change the perge control valve, its on the back of the engine below where the plastic intake pipe meets the metal intake manifold on the back side of the engine between the engine block and the firewall, on the underside of your car hood you will see a vacume system diagram, it will illistrate where the valve is, it should cost about 30 bucks or so at a hyundai dealership

SOURCE: Once I fill up my 2002 Sonata with gas it's hard to start/cut off

check your charcoal canister system, and vauucm line going to it and or solenoid valve in line with it, and even !! a good gas cap !? The canister can purge to the intake manifold as soon as the throddle port opens ,allowing extra fuel during warn up and can cause a rich start condistion!

SOURCE: after i fill up gas tank engine crank but does not start

Purge Control Solenoid Valve stuck 'OPEN" Replace it.

PAUL MC G

• 1280 Answers
• Posted on Oct 19, 2009

SOURCE: 1999 Hyundai Grandeur suddenly stop and couldn't start again

Coolant Temperature Sensor

SOURCE: 2001 hyundai accent, trouble filling gas tank

I have 2002 Hyundai Accent. When fueling, I had to trickle the fuel in to prevent the fuel dispenser from constantly shutting off. Even then I could only get about a quarter gallon at a time between fuel shutoffs. Would take 10-15 minutes to put in 10 gallons. Very frustrating. I found and fixed the problem today. There is a charcoal cannister that is part of the Evaporative Emissions control system. It is located inside the rear fender well on the driver side, behind the driver side rear tire. You cant miss it. Actually looks like a square plastic box and it has hoses coming out of it. I removed the entire charcoal cannister assembly in about 15 minutes. Follow carefully. First, remove the electrical connector to the purge control valve (this valve assemby is mounted to the side of the charoal cannister on a bracket). No big deal. Then disconnect the three hoses that come out from the cannister assembly on the one side that faces the rear tire. Two of these hoses are small diameter about 1/4" and one is larger at about 5/8 inch diameter. Then you remove the 3 bolts that hold the whole cannister to the car frame. Then the whole piece comes out. Once I got the cannister and purge control valve out of the car as a whole assy I found the problem. The larger of the 3 hoses you disconnected as well as the port it connects to on the cannister was packed with the small charcoal pellets and actually formed a solid plug inside that larger hose. I had to stick a screw driver through that hose to knock the plug out that those charcoal pellets had formed. It all makes sense now. When you fill the tank with gas, you also push out air and vapor from the gas tank that is being displaced by the rising fuel in the tank. That vapor is supposed to go through that larger hose to the charcoal cannister where the fumes are removed by the charcoal. If that hose is plugged, like mine was, then the vapor has nowhere to go as you fill the tank and it increases pressure within the tank it causes the fuel dispenser nozzle to shutoff because it keeps detecting a pressure increase within the tank. That's my theory. I don't have the Hyundai design prints to confirm it. I had to tilt the charcoal dispenser so that the pellets came out of that larger hose port on the cannister. Like I said, even the port itself was full of pellets. So I poured out enough to clear the pellets that were in the hose port. I cleaned out the hose. Put everything back and went to go fill with gas. I filled that tank at full bore with no problem. Have the dealer or your mechanic check the ports and the hoses off the cannister. If they are filled with charcoal pellets, that is the problem. That should cost less than some of the fixes I have been reading about here.