How to Improve Fuel Mileage With Cummins Diesel

by Arthur Barnhouse
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The dirty automobile image by Hunta from

Cummins first began to manufacture diesel engines specifically for Dodge pickups in 1989. This would set the standard for other diesel-powered pickups in both horsepower and torque. Throughout the years, the Cummins diesel evolved to include a turbo diesel in 2004 that was rated highest in its class in terms of power and reliability. Of course, with more available power, fuel efficiency must eventually become a concern. If you're driving a Dodge pickup with a Cummins under the hood, there are things you can do to actively improve your fuel mileage.

Step 1

Drive your Cummins-powered truck with optimum fuel mileage in mind. Remember, diesels run most efficiently, and even produce the most torque, when the engine is steadily operating at a lower RPM. Therefore, when driving on the highway, use cruise control to limit the speed of your truck to less than 65 mph. This will keep your tachometer on the low end of the scale and increase your fuel mileage.

Step 2

Shift early if your truck has a manual transmission. This is referred to as short-shifting. Unlike gasoline-powered engines, a diesel engine prefers to be shifted into the next highest gear long before it reaches its peak power. Again, this keeps the truck running at a lower RPM and helps you save money at the pump. If you have a truck with an automatic transmission, just keep in mind that you shouldn't gun the engine more than you absolutely must and use overdrive, if equipped.

Step 3

Buy quality fuel for your Cummins. While it sounds like common sense, cheap, low-grade fuel can be tempting, especially when diesel prices skyrocket. Ultimately, you will increase your fuel mileage by using top-grade diesel fuel and save your engine from future damage caused by watery or dirty fuel.

Step 4

Replace your standard engine oil with a good synthetic. A premium synthetic will permit your Cummins engine to run at optimum performance, as it decreases the level of friction and increases the efficiency of the engine. With the added benefits of cleaner emissions and more horsepower, you'll also experience greater fuel economy. Furthermore, you will notice fuel mileage improvements if you change to higher-grade oils in your differential and transfer case.

Step 5

Purchase a power module designed for your Cummins diesel. There are a variety of brands on the market, so you should look around before deciding which to buy. Once you have a power module, it is simple to install. Usually, all that is required is plugging it in to the proper outlet. After it's installed, the module makes electronic adjustments to your engine, which makes it run more smoothly and increase fuel mileage. It will also give you additional horsepower.

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