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Drove the truck home yeaterday and when I get to 4th high the predetonation knock starts. Can this be the injectors to tight giving me advanced timming.
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M816 predetonation
- Thread starter Floridianson
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- Monrovia, Ca.
No. Does it smoke when this happens?
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No smoke Will and seems to be running ok. When it starts I just go easy on the peddel till the next up shift and easy on 5th high till she gets to 2100. Would this be something because of the GVW of the 816?
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They rattle and bang a bit especially in the colder weather. If the fuel rate has been increased, it will tend to make more noise. A diesel won't "ping". There is no pre ignition on an oil fired compression engine, it is actually a pretty precise deal. Injection timing can be affected by a loose injector setting or air, that's the white/grey smoke. A tight injector will cause a mechanical failure, then it'll smoke,make noise and be rough.
AMGeneral
Well-known member
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From what I can remember my M816 sounded exactly as you describe during the 3/4 upshift and especially noticeable when loaded.
That massive drop in rpms (2100 to 1200) really taxes the power curve of the 250,especially toteing around 36,000 lbs.
Even with new injectors,fully rebuilt injection pump, minimal (if any) air leaks in the fuel system and a clean fuel filter,it still sounded "noisy" while pulling hard.
I eventually took it as "normal" for a heavily laden NHC 250 to sound like that.
I actually had several people in the know to drive my 816,I actually thought it was weak for that size engine, all of them thought it ran great for what it was.
If Clinto still had the video stored somewhere of my M816 towing a M123 tractor,it captured the sound almost perfectly.
That massive drop in rpms (2100 to 1200) really taxes the power curve of the 250,especially toteing around 36,000 lbs.
Even with new injectors,fully rebuilt injection pump, minimal (if any) air leaks in the fuel system and a clean fuel filter,it still sounded "noisy" while pulling hard.
I eventually took it as "normal" for a heavily laden NHC 250 to sound like that.
I actually had several people in the know to drive my 816,I actually thought it was weak for that size engine, all of them thought it ran great for what it was.
If Clinto still had the video stored somewhere of my M816 towing a M123 tractor,it captured the sound almost perfectly.
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Was reading about the Cummins Flush and Adjust to clean the injector tips so I might give that a try. The post I was reading also said they felt that the Flush and Adjust should be used before running the injector clearances. The outher thought would be to put the transmission I have out of a 5 ton miltifuel. Owell Thanks
- 7,408
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- Location
- Interlachen Fl.
Ok been reading and they are calling it fuel knock so whatever. Think like I said, try the Cummins Flush and Adjust you run the motor on for and hour then check the injector clearances for being to tight causing to much advance. Thanks all.