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Thread: bad starting

  1. #1
    Join Date
    Feb 2009
    Posts
    25

    bad starting

    Hi All,

    i have a Proplem with my 2002,6.0 when it is cold and hot he starts very bad no idle,he start only when i push the throttle pedal a little bit what can i do to fix it??? I have 50 psi fuel pressure at idle. What the best idle rpm i have 580 rpm with aTh 700r4 behind i think it is a little to low?
    Scanner reads Code P0134 and P0154
    New ones will comming next week...


    Greetings from Germany

    Hardy

  2. #2
    Join Date
    Nov 2003
    Location
    Denton Texas
    Posts
    20,540
    Get some MAF sensor spray cleaner and wash that thing down. Also check that the IAC solenoid is funtioning. If you have a PCM scanner, see where you IAC counts are running. You might also check the reading on the MAP sensor. Check these sensors for broken wires or shorts while you're at it.

    bad 02s make for a bad idle but the system doesn't really read them until they get up to temp and it goes into closed loop.
    See my truck data in the "My Garage" section here... http://www.ls1truck.com/forums/my-ga...tml#post191709

  3. #3
    Join Date
    Aug 2008
    Location
    North Texas
    Posts
    12,078
    Codes say the front O2 sensors are not responding to the exhaust stream and fuel adjustments provided by the tune. Could be bad O2's causing the code but as mentioned about this would not be the case on a cold start. You did mention hot start too. What is the difference between hot and cold?

    580 sounds a little low for idle setting.

    50 running is barely low at all...what pressure does it make on key on while the pump is running without starting the engine.

    Also make sure the O2 heater fuses in the underhood fuse block are not blown and all the connections are good.

  4. #4
    Join Date
    Feb 2009
    Posts
    25
    When i disconnect the Battery for a while lost the PCM his information stored in its memory and will be re-programmed?
    When Yes how to do this???
    Fuel pressure without idle about 56 psi.
    All fuses are good.
    How can i increase the idle setting a little bit ?

  5. #5
    Join Date
    Aug 2008
    Location
    North Texas
    Posts
    12,078
    The idle speed is determined by the settings in the computer. To raise the idle speed (assuming there are no other problems causing low idle) a tuner needs to change some parameters in the computer. While at it, the tuner should be able to scan the O2 sensor data and do some simple tests to determine the cause of the codes you have. 56 is OK.

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