Sometimes car only starts when I hit the gas

Discussion in 'The Garage' started by Bulldog13, Mar 1, 2008.

  1. Bulldog13

    Bulldog13 Golden Member

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    Once every month or so, I will attempt to start my car (2006 Scion xB automatic) and it will turn, but it won't start. If I turn the ignition and hit the gas, the car will start. It seems to happen about once a month (has happened twice now). Any idea what causes this? I am due for a 45,000 mile service, so I would like to mention it to the mechanic.

    Ideas ?
     
  2. Skunkwourk

    Skunkwourk Diamond Member

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    might be the starter, I had a similar issue in my ES300 before.
     
  3. Zenmervolt

    Zenmervolt Supermoderator<br>The Garage<br>Elite member
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    Sounds similar to flooding. Have the fuel pressure regulator checked out. Also check for leaking injectors. Hard to say with the problem being that intermittent though.

    ZV
     
  4. bctbct

    bctbct Diamond Member

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    map sensor?
     
  5. cardiac

    cardiac Platinum Member

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    OP says it turns over, just doesn't start. The starter is doing its job.

    Just mention to your mechanic just as you did here. He can check the fuel pressure.
    Are you getting a check engine light when this happens?
     
  6. Ronstang

    Ronstang Lifer

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    This one is actually pretty easy if you think about it. On a fuel injected car the air passing into the engine at idle is controlled by a valve. Some call it an Idle Air Bypass or an Idle Speed Control....either way they all do the same thing and that is regulate the amount of air that can enter the engine when the throttle butterfly is closed. When you shut the car off it closes. Sometimes they get a little carbon buildup on the pintle or seat and when it is hot and the car is shut off they can stick together. So basically you have no air going into the engine on start up and by hitting the gas pedal (misnomer on fuel injected cars as all you are controlling is the throttle butterfly angle) you let enough air into the engine to allow it to start. Once started the valve operates as normal.

    I have had this problem when the car would just die at a stop sign and sometimes was hard to start.....it was always the IAB solenoid/valve. Sometimes you can get by with a cleaning. I had this problem intermittently on my Taurus SHO for over 50K miles and never fixed it because it only happened every once in a while and the solution was to hold the accelerator pedal down to start.
     
  7. dug777

    dug777 Lifer

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    My carbied car needs throttle to start all the time ;)
     
  8. M2008S

    M2008S Senior member

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    first, its not the starter. if you turn the engine over, its working. the starter might be weak or etc from all the cranking though. but its not an issue

    as for hitting the gas there is SO MUCH to check out. it can be a fuel pressure regulator. if its stuck open (too much) then when the vehicle runs the exhaust will smell quite gassy.. if its not getting enough pressure obviously it stumbles when you get on it. also your injectors might be stuck or clogged, could be a computer failure or a mass air flow sensor failure. could be a type of sensor like a coolant temp sensor that tells the cpu that the car is cold therefore needs more gas to warm up. could be an iac (idle air control valve.. i dont even know if theres something like that on your car, if so it may be something else).

    i wouldnt recommend ripping into that stuff since its pretty technical and theres many many parts that rely on everything else. i say drive it and see if it gets real bad, if it only happens once a month or so i wouldnt worry about it - CHECK YOUR FUEL FILTER IT MAY NEED CHANGED(few $). if it gets worse take it to a scion dealer!