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engine knock on a 07 6.6 duramax

Discussion in 'Chevy Trucks' started by Chevy 2500 hd, Mar 1, 2008.

  1. Chevy 2500 hd

    Chevy 2500 hd Member
    Messages: 50

    I just got my first diesel in june its the 07 classic 2500hd with the 6.6 duramax has 10,200miles on it and 600hr on the engine I guess the best way to discribe the sound is a knock from about 700 rpm(idle) to 1200rpm the oil pressure is at 40 coolant temp is just below 210, once it goes above 1200rpm and oil pressure goes to 60 it sounds fine and it just started to do it today when I went to plow I guess to me the sound wasn't normal. Didn't know if I should be getting it looked at by the dealership or not?
     
    Last edited: Mar 1, 2008
  2. exmark1

    exmark1 PlowSite.com Addict
    Messages: 1,321

    Well you have a warranty, I would get it looked over before something completely fails!
     
  3. ABES

    ABES PlowSite.com Addict
    from MN
    Messages: 1,322

    Keep bringing it to the dealer until its fixed right eventually they will get sick of seeing it in the shop and they will fix it right. I would be pissed if i gave up 40k for a new truck and the motor started making noise.
     
  4. tuney443

    tuney443 PlowSite.com Addict
    Messages: 1,847

    Why wouldn't you get it looked at---you have a great 5 yr./100K mile warranty? I've had 3 Dmax's----all great trucks-very rare that one gets an engine knock but hey,it's man made--nothing's perfect.Let us know how it goes.
     
  5. lilweeds

    lilweeds PlowSite.com Addict
    Messages: 1,178

    Are you sure it's a knock, diesels do make more know, and a low RPM noise is fairly normal!
     
  6. Chevy 2500 hd

    Chevy 2500 hd Member
    Messages: 50

    Ok I was going to have it looked at no matter what I stated my question the wrong way I want to know if anyone else had this. rsvees I know its norm for them to be loud at low rpm but this noise just started all winter long the truck has perd like a kitten at low rpm but now it makes a loud knock til it hits 1200 and then goes back to a nice smooth sound. I love this truck all the power I could ask for a better truck
     
  7. farmboy52787

    farmboy52787 Senior Member
    Messages: 114

    junk it! go back to a gas job lol, then you dont have to worry about water in the fuel and getting stranded!
     
  8. Spitz

    Spitz Senior Member
    Messages: 192

    I was going to tell you the pilot injection is turning off but that only happens at around 2300rpm+, not at idle through 1700. Definatly would take it in and have it looked over if its happening when its fully warmed up like you stated.. At least if you take it in and have it documented and it blows up later on down the road they have that record of you showing concern..
     
  9. tuney443

    tuney443 PlowSite.com Addict
    Messages: 1,847

    Are you possibly talking about your elevated idle engaging?I mention this because 1150-1200RPM is exactly the point where that feature will take the Dmax.If your engine is real cold{1 of the parameters for engagement},you will get the ''concrete mixer or marbles growling'' type noise or in your mind a ''knocking''.This is completely normal and is a great tool for faster warmups.And just for the record,the Dmax is the quietest diesel at ANY RPM of the 3 diesels out there in any form,from the LB7 to the LMM version.
     
  10. Chevy 2500 hd

    Chevy 2500 hd Member
    Messages: 50

    no I dont have the elevated idle option I only have the LT1 so there are no steering wheel controls and anyways its already up to temp and plus I keep it plugged in
     
  11. OhioPlower

    OhioPlower Senior Member
    Messages: 440

    Your truck has elevated Idle. My 07 dump has elevated idle and its the base trim level. I cant remember how to turn it on though, its in your manual
     
  12. tuney443

    tuney443 PlowSite.com Addict
    Messages: 1,847

    Yes,you do have the elevated idle.Take out your supplement and do a read.I don't have the programmable wheel either.And even with what you do,another parameter of the elevated idle to engage is the outside air temperature.If you have it engaged and it's colder than 32*,it will come on.
     
  13. Chevy 2500 hd

    Chevy 2500 hd Member
    Messages: 50

    ok but why would it be on the trucks up to temp when it first started idk im still going to take it in rather then ignore it and have everything go to hell. Thanks for the info thow I'll have to go read and see how to turn it on
     
  14. Chevy 2500 hd

    Chevy 2500 hd Member
    Messages: 50

    Ohio plower you turn the ign to run hold the throttle all the way down press the brake 3 times in 8 sec it will flash on the screen elevated idle on or off. Tuney443 it says it will turn off by its self which idk maybe theres a bad sensor but I could tell the dif with it on so I really don't think its that. this is what a gm tech said on another site thats all about the duramax gmtech4 possible fuel knock,they should check your balance rates and find the injector that is the culprit,take it in
     
    Last edited: Mar 2, 2008
  15. tuney443

    tuney443 PlowSite.com Addict
    Messages: 1,847

    Having trouble understanding you some. What does idk stand for? If you got your info from a GM tech at the DP,your in good hands. The elevated idle will turn off by itself,but only when certain parameters aren't met.Once you hit your brake or clutch,it would also disengage.Keep us posted.
     
  16. OhioPlower

    OhioPlower Senior Member
    Messages: 440

    idk= I dont know
     
  17. Philbilly2

    Philbilly2 2000 Club Member
    Messages: 2,634

    If you know someone who has a Preadator Box (programer) you can check your own balance rates.

    The knock that you sound like you are having has nothing to do with the fact that your high idle is on or off. To me it sounds like the high idle will just cover up the problem. It will stil knock until the high idle engauges.

    Your oil pressure sounds right by the gauge.

    I would get your balance rates checked. If one injector is not firing properly, that could cause a knock from lack of fuel at the correct time.
     
  18. tuney443

    tuney443 PlowSite.com Addict
    Messages: 1,847

    I thought this as a possibility Philbilly because I;ve seen some Dmax owners get spooked when they hear the engine spool up for the first time in elevated idle,especially if it's real cold.Now that we know more about what's going on,your hunch is probably right.He doesn't need a Predator or any other programmer right now though because he's still under warranty. If it is an injector problem,the dealer will fix it.
     
  19. Philbilly2

    Philbilly2 2000 Club Member
    Messages: 2,634

    No, I was just saying to use the Preadator box to check the balance rates. The Preadator box has a function on it where you can plug it into any truck even if the tune is installed in another truck. You start the truck and check the balance rates of all eight injectors. If all of the numbers are the same, your fine. If one number differs, then you know when you got into the dealer that you have an injector problem and they can't give you the normal run around.
     
  20. Yaz

    Yaz PlowSite.com Addict
    from NH
    Messages: 1,061

    Just take it to good dealer that services diesels, not just any one. Most dealers don't have a good Diesel mechanic so it's important to find one that does. Hopefully it's just a injector sticking. If it wasn't under warranty I would try this.. Guys that have had this problem say to run some diesel additive in large dose or 2cycle in fuel to clean the injector.