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Thread: 2003 Duramax Tuning Knock?

  1. #1
    New Member 03twinduramax's Avatar
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    Arrow 2003 Duramax Tuning Knock?

    I have just recently replaced the motor in my 2003 chev duramax with a 2002 lb7. It got brand new Bosch injectors along with head studs put in it back in December 2013 when the engine went in. The truck has EFI live tuning from Nick at duramaxtuner.com in Illinois . After driving the truck about 600kms after all this was done it started to knock on higher rpms but go away with low rpms with No smoke. Took the truck to Smoke Em' Diesel Performance in Sask. to get the injector rates tested as they did the work. All checked out good for the new injectors balance rates, BUT the timing did show it was running 38* when it was tuned with the EFI to be 27*. After coming to the conclusion it was the tuning off, they sent the ECM down to duramaxtuner and after they had a look at the ECM it is saying that its giving the proper tunes and degrees in timing as was loaded on before. Bob said he's never really come across this and same with the guys at smokem diesel. Truck has run with the original 03 engine for 2 years with this tune and now acting up within 600kms of a different 02 engine. Has anyone heard of this happening before like timing changes as you drive? Its got all us stumped here not knowing what to look at next why this would happen. Any and all help is needed and appreciated!

  2. #2
    Lifetime Member vortecfcar's Avatar
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    We've discussed the issue with Smoke 'em diesel. The only possibility we can see is a defective fuel temp sensor or inaccurate data from the tech's scan tool.

    Nick

  3. #3
    Lifetime Member Dmaxink's Avatar
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    Quote Originally Posted by 03twinduramax View Post
    I have just recently replaced the motor in my 2003 chev duramax with a 2002 lb7. It got brand new Bosch injectors along with head studs put in it back in December 2013 when the engine went in. The truck has EFI live tuning from Nick at duramaxtuner.com in Illinois . After driving the truck about 600kms after all this was done it started to knock on higher rpms but go away with low rpms with No smoke. Took the truck to Smoke Em' Diesel Performance in Sask. to get the injector rates tested as they did the work. All checked out good for the new injectors balance rates, BUT the timing did show it was running 38* when it was tuned with the EFI to be 27*. After coming to the conclusion it was the tuning off, they sent the ECM down to duramaxtuner and after they had a look at the ECM it is saying that its giving the proper tunes and degrees in timing as was loaded on before. Bob said he's never really come across this and same with the guys at smokem diesel. Truck has run with the original 03 engine for 2 years with this tune and now acting up within 600kms of a different 02 engine. Has anyone heard of this happening before like timing changes as you drive? Its got all us stumped here not knowing what to look at next why this would happen. Any and all help is needed and appreciated!
    I have had this happen before... Not a "fix" but a band aid is to use the maximum timing table(s) as the max you want to hit for x mm3 and x rpm. Sucks, but works.
    -Kory

    I'm out of ideas? Nah trick... When in doubt, 0xFFFF it out!

    http://www.PPEI.com/

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  5. #5
    Lifetime Member Dmaxink's Avatar
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    Quote Originally Posted by vortecfcar View Post
    It was already set well below 38 in the original tune. If it's truly 38 degrees, it's coming post max limiter somehow.

    Nick
    Ah... It's being a ash hole.
    -Kory

    I'm out of ideas? Nah trick... When in doubt, 0xFFFF it out!

    http://www.PPEI.com/

  6. #6
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    The main plausibility we can see is an imperfect fuel temp sensor or mistaken information from the tech's sweep device.

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