Tuners intercept the signal that the ECU or engine control unit shoots out to the injection system, allowing precisely the correct amount of fuel to be squirted into the injectors. This is will create noticeable gains in torque and power. The modern diesel engine is packed to the brim with sensors that are manipulated and told what to do by the Engine Control Unit of a vehicle, so tuners are a great way to help the engine to run efficiently. Fuel consumption will even show gains as the vehicle will be using less throttle than it used to.
These tuners even allow for changes as minute as injector open time, allowing the perfect amount of fuel to enter the system, increasing torque and horsepower output. Some add as much as 100 horsepower and 200 lb/ft of torque! Pyrometers are a common addition to tuner packages, as the monitoring of EGT levels is very important after a tuner is installed. Transmission shifting patterns are another common change made by a tuner, which will assist in matching the rest of the truck’s increased level of performance.