Cm870 vibration concerns
07-13-2021, (Subject: Cm870 vibration concerns ) 
Post: #1
Cm870 vibration concerns
My w900 cm870 485 hp with 390k has a heavy vibration at 12-1300 rpm and a high frequency vibration under power 15-1800 rpm. Boost will max at 38 psi, no pyro but installing one ASAP. Absolutely no smoke at all even at max throttle. It’s not a hard pulsing vibration like an injector miss, but more of a buzz that goes away when you let off throttle.

The truck has all new tires, complete new driveline due to replacing a meritor 10 speed with a brand new Eaton 18918b. All that has been eliminated even though I feel the frequency is to fast for anything drivelive related. I just completed a Full egr tune up done and overhead just run.
My local cummins dealer has made sure the factory tune is in truck. (Not sure how much I trust them)

What It feels like is when you advance the pump on a old mechanical diesel injector pump and you start getting power vibration. Is it possible for a factory tune to have too low of crank angle?
I’m a machanical diesel guy so I’m still learning this Isx.

I have spoke to “running rough” some time ago about getting programming checked out but is there something else I should look for first. The motor doesn’t run bad really I just want to KNOW it’s correct.I want to run a leak down test and cutout to rule out a leaking injector but that really should be done anyway.

Should I have programming double checked first ?

Thanks for any input.
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Cm870 vibration concerns - Precisionw900 - 07-13-2021



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