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Bad mileage and gas smell

edited December 2011 in Repair and Maintenance
Dear Ray and Tom my van is using way too much gas.I can smell gas at tail pipe and can feel the express pressure when it explodes in exhaust pipe.I changed plugs,wires,distributor cap and rotor and still exactly the same thing .It also floods out easy if i dont keep my foot on gas pedal at a stop.I been told by people that it could be one or more sensor but is there a way to tell if one is bad or what .Im a poor working man and cant afford to throw 100 dollar bills at it. If you could narrow down what sensor(s) I should look at where they are located I would greatly appreciate the help


  • First off....This is NOT a forum for Tom and Ray. Just other car enthusiasts..some are mechanics..some just like cars.

    What year is your truck???

    I'm assuming that this is fuel-injected. It sounds like it's flooding. Too much gas and not all of it is getting burned up when existing the exhaust. This is NOT a good situation. First it can destroy the catalytic converter...and second it can dilute the engine oil.

    Knowing the model year will help determine what the cause could be.
  • Is the van getting up to normal operating temperature? (dash temp gauge reading normally? heat ok?)
  • Ditto to Mike's post. The truck's mileage never hurts to know too.

    My wild guess is that you either have a leaky injector or a cylinder not firing. It needs lookin' at.
  • edited December 2011
    The problem might be with a leaking fuel pressure regulator. The fuel pressure regulator is usually located somewhere on one of the fuel rails. It's a small canister with a single vacuum hose attached. Locate the fuel pressure regulator and remove the vacuum hose from the fuel pressure regulator. If gasoline leaks out of this vacuum connection the fuel pressure regulator is defective and requires replacing.

  • Don't forget the O2 sensors....if they are bad....then the vehicle will default to run the engine as RICH as it possibly can by default....since it cannot lean itself out any longer without O2 inputs.....this will make you CHUG-A-LUG will smell raw fuel from the tailpipe also.....BIG BIG fuel waster...

    Also what on earth are you talking about when you said "I can smell gas at tail pipe and can feel the express pressure when it explodes in exhaust pipe"

    For Gods sake I certainly hope that there is no EXPLODING of any sort ANYWHERE near your vehicle.... I think you are trying to describe something else here and are lacking the vocab..... Help me out on that one.

  • Gives whole new meaning to the term "secondary combustion".

    Hey, the cat converter can reach over 800F. A candle flame is, what, only 750F? A bunch of free hydrocarbon molecules surrounded by oxygen hits that and POP!
  • edited December 2011
    the van is a 2002 chevy express .Yes i can smell gas from tailpipe and can feel excess pressure when it pops .The only way to keep it running at a stop is with foot on brake and gas
  • the van does get up to normal temp
  • where do i find these O2 sensors
  • The oxygen sensors are located in the exhaust stream(s), just fore and aft of the primary catalytic converter.

    With respect, allow me to suggest that your lack of knowing where to look for the oxygen sensors, combined with your not recognizing that the suggestion is only one of many possibilities, implys that you may intend to replace parts until the problem disappears. If this is true, you may just save a ton of money and prevent a more serious problem, by just taking the vehicle to a reputable local shop.
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