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  1. #1

    Default White Smoke from leaking injectors

    I just purchased a 2005 Suburban with 5.3L. I've noticed on occasion I get white smoke and strong fuel smell at startup at tail pipe. Usually worse after shut off for about 2-4 hrs. Not as bad after sitting overnight or days. Also, after initial puff of smoke, I get a very steady consistent white smoke (looks like vapor) until the engine reaches normal operating temperature. I get lots of water from the tail pipe until it reaches normal temp. No coolant loss or sweet smell of antifreeze. Could this be a leaky fuel injector? I haven't checked fuel pressure yet...I thought I'd ask on the forum to get a feel if anyone else experience this. By the way, fuel economy is okay...about 16 mpg, power is great. I thought the puff of smoke could be leaky valve seals, but the smoke is white (not blueish).

    One final note....when engine starts...I hear a slapping sound for a split second, on occasion. I'm thinking flooded cylinder due to leaking injector. What do you guys think?

    I can afford mechanic...I have to do the repairs myself. I'd like to have a well informed approach rather than replacing this, replacing that! Any feed back is welcome! Thanks!

  2. #2


    I have an 05 yukon xl with the 5.3l. I do notice that there is occasionally white smoke also. I usually notice mine after it is warm and I back into my garage. It dissipates very quickly. I had an 03 yukon xl 5.3l that did the exact same thing. I always chalked it up to moisture in the exhaust system. Both of my yukons and my cousins 04 seam to drip tons of water out of the exhaust. I would think that if your injector was leaking that badly it would not have a good spray pattern and would cause a misfire or a rough idle. While I have seen leaking injectors cause white smoke, it was one time and the vehicle had well over 300,000 miles on it. Multiple times I have seen black smoke from a injector that was leaking severely, causing the truck to run rich.

    1995 Silverado 4x4
    6" BDS Suspension Lift-3" Body Lift-Add A Leaf in rear -Trailmaster SSV Shocks-Duel Steering Stabilizer Kit -AirAid Cold air intake-
    4.56 Gears with Detroit Auburn Locker-Pro-Comp Traction Bars with duel shocks-Aluminum Skid Plate Kit-38.5" x 16.5" Mickey Thompson Baja Claws-Constant Dropping fuel gauge

    2005 Yukon XL Jet Power Programmer, Bilstein Shocks, Bilstein rear springs, Helwig Anti-sway bars, EGR Window Visors, EGR Hood Shield, Denali Headlights, Headlight harness upgrade, GE NightHawk Bulbs, White Night Rear lighting system, Russell Braided SS brake lines, PowerStop Brake pads, PowerStop cross drilled and Slotted Rotors,
    2002 Silverado ext cab 2wd (Sold)
    2003 Yukon XL (Totaled)

  3. #3
    Jr. Mechanic
    Join Date
    Apr 2013
    East Central Iowa


    Check the fuel pressure regulator located in the rail drivers side. Pull the vacuum line off and start the engine. Look for fuel leaking from the port on the regulator,either while running or shortly after shut off. If it is leaking it can flood raw fuel into the intake.

  4. #4


    White smoke is usually water vapour. This is normal when the engine is cold, it is just condensation in the exhaust pipes.

    If the white smoke continues after the exhaust is warm/hot then there is a coolant leak into one, or more, cylinders.

    A leaking injector should cause a hard start followed by a dark gray to black smoke for a few seconds.

    The noise you are hearing is called piston slap. Again, normal. It should go away as the block heats up.

    '09 Avalanche LTZ - Black
    '05 Envoy XL (sold)

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