06 lly knock at 1300-1700 rpm

Kansas2500hd

Kansas2500hd

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Dec 15, 2013
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Kansas
I have a 2006 duramax that has a knock at 1300-1700 rpm only when warm. No white smoke and only mods are a k&n filter, and turbo back exhaust. Also have a bullydog programmer on Eco tune. It runs and drives fine. Started about a week ago when I was going up an incline. Been doing it ever since. I have never towed anything with it since I've owned it. Any advice or ideas would be appreciated. thanks!
 
J

jkholder09

New member
Jan 8, 2012
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Maryland
I just had 2 medium duty engines come in large chunks missing from cam.
I had another 2500 engine last week. Piston pin bushing in rod spun.
All 3 lly all 3 sounded like your description.

A broken rocker or valve might pop bsck through the intake.

Injector and fuel knock are also possible.
Keep your fingers crossed.
Try and isolate the cylibder then swap injectors hopefully its a quick fix.
If not find a good shop to take it to.

from mobile
 
J

jkholder09

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Jan 8, 2012
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Wow that sure does sound like its in the engine. That hard of a knock and no white smoke really starts to rule out an injector.
Can you kill cylinders and see which one is knocking?

from mobile
 
PureHybrid

PureHybrid

Isuzu Shakes IT
Feb 15, 2012
3,439
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Central OH
Generally a spun bearing or bushing won't be a constant knock like that unless it's completely gone IMO. A bearing will spin, then stop, and start spinning more. I would say do a cylinder cut out if possible, then pull valve covers to check the overhead.

It is possible to have a harsh fuel knock like that with little to no smoke.
 
Kansas2500hd

Kansas2500hd

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Dec 15, 2013
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Yeah there is no white smoke at all. The motor only has 90k on it is the crazy thing to me. I just bought it and the knock started about a week after I bought it. Haven't even made the first payment. Hopefully I can find a good mechanic to take it to.


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J

jwrkansas

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Mar 3, 2012
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There's a guy over in downs, ks Austin Thomas AT performance diesel . He's pretty good and should be somewhat close iirc
 
Kansas2500hd

Kansas2500hd

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Dec 15, 2013
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Kansas
Another question- is it terrible for me to drive it around town? It's the only vehicle I own and have to get to school everyday.


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P

poberly

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Mar 14, 2013
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Is the sound there every time you accelerate in those rpms? Like if you are easier or harder on the peddle does it go away or sound different?
 
not quick

not quick

Jay
Nov 3, 2013
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Middletown, Ohio
Mine does kind of what your talking about from 1700-3000 with no load on the motor. Give it some pedal and it goes away. Just figured it was normal, maybe not.
 
Kansas2500hd

Kansas2500hd

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Dec 15, 2013
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Kansas
This is probably a stupid question, but how do I test to see if and which injector is bad? I've also read that sometimes the connectors just go bad. How would I know if this was the case? I have the day off tomorrow and really would love to get the problem diagnosed and parts ordered.


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