Exhaust problems with cat conv and glowing red hot

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My son has a 1999 Hyundai elantra that started acting really sluggish about a month ago. I noticed it had an exhaust leak and we looked at the front cat ( they have 2) and it was glowing red hot. The flexible exhaust pipe connected to it was glowing red hot and torn in half, hence the leak. First thought was back pressure from lower cat. Had to replace upper car and flex. Did that and started car. Car started fine and sounded great for about 5 minutes. Noticed lots of white exhaust and fuel smell. Looked at new cat and of course it was glowing red hot. Looked at spark plugs. Two of them looked fouled with strong gas smell. Changed those and fired car up. Again sounded great for 5 minutes. Again cat starts to get hot. Thinking upstream o2 sensor or fuel pressure regulator. Everything I read leads me to believe there is too much fuel being burned in catalytic converter. Please help. Have good mechanic skills but diagnosing this is testing my limits.

Cjboring in Kettle Falls WA

Jan 20, 2015

2 Replies

Popular Answer

HyundaiUpThePipeon Apr 4, 2016

That is sexy as hell... Nothing like watching a blonde drive a Hyundai and pour gasoline into her catalytic converter and waste fuel like that... They should rip off all the catalytic converters and fill the air with exhaust - it smells soooooooo good and sexy and nothing like a hot chick flooring exhaust into the air - fuck yea. Stick your dick right up the Hyundai and feel the pressure - nothing sexier!!!!!!!

CharlesAutomotiveon Jan 20, 2015

Something is dumping too much fuel. Could be a injector stuck open. Could be a misfire from a coil not firing, or the fuel pressure regulator. Usually a pretty reliable car.

Cjboringon Jan 26, 2015

After going through the plugs and wires we checked the coil and it seemed to be bad. Just put new coil and wires in today. Fired car up and strong fuel smell from exhaust for about a minute and then it was gone. Drove it around a bit and looked at upper cat and it was fine. Exhaust then seemed to be full of water or steam. Had son open it up on road and everything looks good now. Might have just had to blow out crap sitting in exhaust and cat. Was definitely coil or wires cause that did the trick. Thanks for reply.

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