Cummins 605/2050 immediate RPM drop issue

[WICT800]

Hello I’m new here and my company recently let me spec a new T800 with a Cummins 605/2050 CM2450 engine 18 speed, now the issue I am having is in between shifts or even just revving the truck at a stand still the rpms will immediately drop off and the air throttle actuator will close, my local Cummins dealer seems to think this is “normal” but after speaking with many others it’s in fact not normal at all which is pretty obvious to me. I was recently told there is a perameter that can be changed on Cummins insight that will solve this issue but I was not told what exactly to look for, any help is greatly appreciated

[tree98]

I don't know how familiar you are with new emissions engines but they drop rpm very fast because of back pressure that the old engines didn't have. I have a 9 liter cummins that you have to rev out the max and shift quickly or you'll miss the gear because it's dropping rpm so quickly. Not saying this is your problem just throwing it out there.

[WICT800]

(10-21-2021 )tree98 Wrote:  I don't know how familiar you are with new emissions engines but they drop rpm very fast because of back pressure that the old engines didn't have. I have a 9 liter cummins that you have to rev out the max and shift quickly or you'll miss the gear because it's dropping rpm so quickly. Not saying this is your problem just throwing it out there.

I’ve driven a few and mine is certainly a step above anything I’ve seen, a few of my buddies have also sent me videos of there CM2450 trucks and theres will rev up and down at a similar rate, my air throttle will slam shut dropping the RPM as if the Jake brake was on, we’ve also connected to it with Cummins insight and it shows air throttle valve position changing while it does it.

[tree98]

Take it back to the dealer and have them reflash it.

[WICT800]

(10-21-2021 )tree98 Wrote:  Take it back to the dealer and have them reflash it.

The truck has been updated several times, unfortunately I have little to no support from my local dealer. I have a meeting at Cummins tomorrow to hopefully begin the process of getting this issue settled, to my knowledge this adjustable within the ECM, just gotta figure out where

[tree98]

If it's been flashed several times it's not gonna be a changeable parameter in insite, It must be something else.

[marek4792]

It seems to be normal for the rpms to drop like a brick on these x15's. I have to hold the accelerator slightly on mine so the transmission (13speed manual) will catch the next gear and not fall into the "black hole".

[WICT800]

(10-21-2021 )marek4792 Wrote:  It seems to be normal for the rpms to drop like a brick on these x15's. I have to hold the accelerator slightly on mine so the transmission (13speed manual) will catch the next gear and not fall into the "black hole".

But to my knowledge it is adjustable, I’ve witnessed several others who have smooth running motors both accelerating and decelerating.

[tree98]

So are you having trouble shifting because of this or what's the issue?? What's your rear end ratio?