2008 Tahoe Fuel Delivery Issue?

Discussion in 'Engine & Drivetrain' started by NarcolepticNugget, Jan 11, 2018.

  1. iamdub

    iamdub I'm 'onna hafta spank youuuuu!

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    This changes things. Hook up a mechanical fuel gauge with a long enough hose to locate the gauge on the cowl and watch it while test driving? Maybe the fuel pump is losing power when the driveline torques? Kinda farfetched, though. Either way, I'm leaning toward an electrical circuit failure.

    When he says "command fuel", does he mean the PCM raises the injector duty cycle?
     
  2. NarcolepticNugget

    NarcolepticNugget TYF Newbie

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    I'd have to ask him for clarification on that but this is becoming quite the nightmare vehicle.
     
  3. swathdiver

    swathdiver Full Access Member

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    The fuel system components can be tested individually with the Tech2. This will quickly expose the offending part.
     
  4. kbuskill

    kbuskill ***CAUTION*** I do my own stunts!

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    Which engine do you have?

    Is it Flexfuel equipped?
     
  5. NarcolepticNugget

    NarcolepticNugget TYF Newbie

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    5.3L & yes it is flex fuel equipped.
     
  6. swathdiver

    swathdiver Full Access Member

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    Should be an LMG iron block motor. Don't think they got the LC9 until 2010.
     
  7. kbuskill

    kbuskill ***CAUTION*** I do my own stunts!

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    I know the older Flex fuel trucks had an alcohol sensor to detect the alcohol content in the fuel. I'm not sure about the newer trucks. If it were giving an incorrect reading perhaps the ECM would be using the wrong fuel tables.... although I would assume the O2 sensors would try to correct it.
     
  8. swathdiver

    swathdiver Full Access Member

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    Not the GMT900s. But if the Fuel Trims get out of whack as they did on another truck here recently, they can be reset by the Tech2.
     
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  9. NarcolepticNugget

    NarcolepticNugget TYF Newbie

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    I'll have to look into getting it scanned w/ a Tech2 but, as far as O2 sensors go - I only have Bank 1/2 Sensor 1 for each side as the rest were deleted/removed when I put my exhaust on. The downstream sensors were disabled via the tune.
     
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  10. swathdiver

    swathdiver Full Access Member

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    You didn't by chance use any downstream sensors to replace an upstream sensor? They are different part numbers.
     

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