2019 - 6.6L Durmax Performance

Fishing Cook · September 17, 2019

I have a 2019 2500hd Silverado with the Duramax. I have a question about the performance of the engine. This dose not happen all the time. But, it seams that every 5 days or so, the engine acts as if it is towing. The rmps are running higher at idle. The fuel mileage goes down from 18-20 mpg down to 12-14 mpg. When I shut the engine off, there is is a noticeable repetitive ticking sound. Tick every second or so. This will last maybe 3 on-off cycle and sometimes during the last cycle, it will revert back to what I call normal operation. Usually, I get 16-18 mpg around town and 20-22 mpg on the interstate, cruising not towing. Is this normal? Is the computer doing something? Any help would be greatly appreciated.

Of course, the person at the service department said I'd have to bring it in when this was happening.

fc

cmysstailights · September 17, 2019

Is it the def cycle, higher rpms could be computer trying to clean system.

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newdude · September 17, 2019

49 minutes ago, Fishing Cook said:

I have a 2019 2500hd Silverado with the Duramax. I have a question about the performance of the engine. This dose not happen all the time. But, it seams that every 5 days or so, the engine acts as if it is towing. The rmps are running higher at idle. The fuel mileage goes down from 18-20 mpg down to 12-14 mpg. When I shut the engine off, there is is a noticeable repetitive ticking sound. Tick every second or so. This will last maybe 3 on-off cycle and sometimes during the last cycle, it will revert back to what I call normal operation. Usually, I get 16-18 mpg around town and 20-22 mpg on the interstate, cruising not towing. Is this normal? Is the computer doing something? Any help would be greatly appreciated.

Of course, the person at the service department said I'd have to bring it in when this was happening.

fc

The every 5 days is the DPF performing a regen. Try as much as you can to complete a regen when you see the MPG drop as it will ensure proper cleaning. Shutting it off during a regen may result in a "Drive vehicle now" message upon a restart.

On the noises. All normal. A few things:

Quote

16-NA-372: Information on Engine Noises Commonly Heard on 6.6L Diesel Engines

This is a rhythmic ticking that can be heard during deceleration. This noise is usually but not limited to being heard from about the passenger side of the vehicle. This noise is the fuel injectors firing (one injector per deceleration and not always the same injector) and is a normal function of the engine and calibration system.

You may hear some noises from under the hood after the vehicle has been turned off. You will notice that they are the same noises most every time the engine is turned off. These noises seem to be coming from the turbocharger and/or the intake air valve. These parts will cycle after the engine is turned off and it is to be considered a normal condition.

Lastly, you may hear a tick noise from under the vehicle and typically heard at low vehicle speed and especially next to a building, like when going through a drive through. This is the DEF Injector and again is normal noise.