Turbo Charger Not Boosting

Discussion in 'General Chevy & GM Tech Questions' started by DocEvil, Dec 31, 2008.

  1. DocEvil

    DocEvil New Member

    I have an '04 3500 Siverado with 6.6L Turbo Diesel. The problem is the turbo charger is not showing any boost. The truck is equipped with a boost gauge, so not only can I see no boost pressure, I can certainly feel the truck is down on power. This problem has occurred twice in the last couple of weeks. It has been quite cold (-20C or -4F) lately and this may be the cause.

    But I'm wondering if anyone else has seen this problem?
  2. 95CTburb19

    95CTburb19 Epic Member 5+ Years 1000 Posts

    are you smoking alot? If you weren't boosting you would probably be pouring black smoke. Boost gauges can be installed wrong and can get screwed up by very cold weather. My friend had a similar problem at school with his wrx.
  3. DocEvil

    DocEvil New Member

    Both times it happened at night so I didn't notice if it was smoking. The boost & EGT gauges are both working fine. The engine seems to run okay as well. Just no power. So far, it's been an intermittent issue. I'd sure like to know if this is just something caused by the cold or if I'm about to be staring at a bigger problem...
  4. dwill3015

    dwill3015 Epic Member 5+ Years ROTM Winner 1000 Posts

    Welcome to the site! Are you throwing any codes at all?
  5. DocEvil

    DocEvil New Member

    No Boost

    Nothing. I will hook it up to a diagnostic unit and see what comes up.
  6. phoebeisis

    phoebeisis Epic Member 5+ Years 1000 Posts

    This is a crude guess, but Is it possible for the waste gate or pop off valve to get stuck open by the cold. Maybe it can get iced frozen open??

    Strictly a guess and I'm not even sure how boost is regulated in a modern motor.

    Happening at night-when it is coldest- might favor the frozen open theory? Maybe you could take a propane torch to whatever regulates boost-? If it works after heating??

  7. tbplus10

    tbplus10 Epic Member Staff Member 5+ Years 5000 Posts Platinum Contributor

    I had icing problems with one of my trucks last winter in real cold weather, the pop off was icing up and sticking open, as noted it was accompanied by heavy smoke. Havent had problems yet this year, but the truck hasnt been in real cold weather yet this year.
    The turbo was spinning and making boost but everthing was being dumped, a couple times it got so bad the truck almost died.
  8. ct9a

    ct9a Epic Member 5+ Years 1000 Posts

    Another possibility is that the motor might be going into limp mode (not sure how the ECU is set up on these trucks). I know with my Evo, I would get over boost scenarios in the cold weather and it would throw the ECU into limp mode.

    If that's not the case, than I would look into the dump valve (pop off valve?) and waste gate being stuck opened. Can you hear the turbo spooling up at all?
  9. DocEvil

    DocEvil New Member

    Well thank you all. It does appear to be a freezing problem. The turbo is spooling up but the waste gate is sticking open. Needs to thaw, dry up & a little cleaning.

    Aloha from the Great White North...

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