So you’ve decided you want to tune your 6.7-liter Cummins with EFI Live for more power, but the process of dealing with bypass cables and flashing software looks complicated.

Kyle Redekopp from Dark Iron Diesel just dropped a detailed guide showing how to do the job yourself with a common EFI Live kit, breaking the entire process down step-by-step.

EFI Live: Preparation is Key

Before any tuning can happen, a few preparation steps are required. First, owners need to identify their transmission to ensure they order the correct tune file; a dipstick on the passenger side indicates a 68RFE, while one on the driver’s side means it’s an Aisin.

For this specific 2018 model, Kyle demonstrated the most critical preliminary step: installing a security bypass cable. He explained that “if you have a 2018 truck, you need to install a bypass cable, and like I said, if it’s older than that, you can skip this step entirely.”

The process involves carefully de-pinning two specific wires from the back of the OBD2 port and replacing them with the wires from the new cable.

EFI Live: Flashing the Tune

With the prep work done, the actual tuning process is pretty straightforward. After connecting a battery charger, the EFI Live AutoCal device plugs directly into the OBD2 port.

From the main menu, the user selects “Program Full,” chooses the correct tune file (in this case, a CSP4 switch-on-the-fly file), and begins the flash.

The device uses its single included license to pair with the truck. Kyle notes that patience is important here as it can take 15 to 20 minutes to finish. Once the flash is complete, he highlights another important action: “after you tune these trucks you must unplug the throttle valve.”

Installing the Switch

The final step is installing the CSP4 rotary switch, which allows the driver to change between the four different tune levels. Kyle showed how to modify the common 5-position switch to work as a 4-position unit by simply relocating a small notched washer inside.

He then drilled a 3/8-inch hole in a dash panel for a clean installation. The switch’s wiring harness conveniently uses a pass-through design, plugging into the factory OBD2 port while providing a new port, so the diagnostic access is retained.

Tackling the Job Yourself

Thanks to Kyle Redekopp of Dark Iron Diesel, you now have an idea that tuning a modern diesel truck is actually doable even outside a professional shop.

With a complete kit and a clear guide like this one, owners of 2013-2018 6.7-liter Cummins trucks can still unlock the performance they’re looking for right in their own garage.