New Vibration At 1100-1300 RPM?

[bajaben]

Good afternoon, my fellow Cummins gurus!

I have picked up a very notable vibration in the truck at 1100-1300 rpm.

I have eliminated the possibility of the vibration from the drive train, i.e., transmission, driveshaft, diffs, or wheels.

The vibration occurs when the engine is at 1100-1300 RPM, whether in park, neutral, or everyday driving.

The engine's load has not made a difference as well.

I first noticed it after I towed my trailer and parked it.

I came back a few hours later to drive back home with the trailer, and the vibration was there.

Thinking it could be related to the trailer, I unhooked it and drove around, and it was still there.

I let the truck sit overnight and cold soak, and the following day, I started it up, and the same thing happened.

It does not seem to affect drivability or power.

A few notes: I need to replace the CP3; it has a very high fuel return rate (a very good local diesel shop diagnosed this), which is on the list to get replaced very soon.

I will also install a new set of injectors to replace the CP3.

Is it possible that my new vibration is injector-related?

I have inspected the truck to try and find anything loose or missing, but I cannot find anything.

Any guidance on this would be super helpful.

I hope it is a bad injector or something like that since I will be replacing them in 2 weeks.

130,358 miles on the truck.

I either commute on the hwy or tow my 43ft gooseneck trailer.

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[AK Bob]

Since you suspect possible injector problems, I would do an injector Kill test to check for cylinder contribution issues.

Other possibilities include harmonic balancer and motor mounts.

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[bajaben]

I've tried the injector kill test in the past, and I couldn't get the test run for some reason.

I am using AlpaOBD.

I will look at the motor mounts and balancer.

Thank you for the good ideas.

I'll check that in the morning.

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[bajaben]

The motor mounts are good, and I performed the injector kill test.

It went as expected, so there were no dead injectors.

I am still stumped.

I'm still leaning towards my injectors "starting to go bad."

I have an appointment on Monday with my diesel shop.

Hopefully, they can narrow down what is happening.


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[AK Bob]

The motor mounts are good, and I performed the injector kill test.

It went as expected, so there were no dead injectors.

I am still stumped.

I'm still leaning towards my injectors "starting to go bad."

I have an appointment on Monday with my diesel shop.

Hopefully, they can narrow down what is happening.

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Please keep us posted.

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[watersupply189]

Harmonic balancer, maybe?


2016 Ram Laramie 3500, G56, 6.7, CC, 4x4

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[bajaben]

Harmonic balancer, maybe?

2016 Ram Laramie 3500, G56, 6.7, CC, 4x4

How would you test that?

I got under the truck yesterday and looked at it while it was running at 1100 RPM, and it appeared okay.

Not sure how to check it.

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[AK Bob]

How would you test that?

I got under the truck yesterday and looked at it while it was running at 1100 RPM, and it appeared okay.

Not sure how to check it.

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The harmonic balancer on our RAMs is a viscous design with a speed indicator.

Look for any physical damage, cracks, or fluid leaks.

See the attached information.

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[Corkey]

Knock on wood; I am curious if the converter is possibly acting up or starting to show signs.

You noticed it after towing the trailer and parked it.

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[bajaben]

Knock on wood; I am curious if the converter is possibly acting up or starting to show signs.

You noticed it after towing the trailer and parked it.

So I thought that as well.

It is a new transmission.

I had a fully built BD Diesel transmission installed at 105k.

So, I only have 25k on the transmission.

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