What’s The Best Tuner for My 6.7L Cummins?

If you’re in the market for a tuner for your 6.7L Cummins - it won’t come as a surprise to you that there are countless different options available for the 6.7L. We decided to try and offer some information to try to help you decide what’s right for you, and why we use what we use at the shop. 

At their core, most of the tuners on the market are essentially the same, the tuner rewrites your ECM to run at different parameters while driving. You can either purchase a box tuner that is preloaded with multiple tuning files (aka Canned Tune), or custom tune files. Every company that produces these tunes is competing to achieve the same thing: Maximum Power, Fuel Mileage, and Drivability. I’m by no means a professional tuner, however, I understand the basics. Typically, to achieve these results, each tuner will adjust the fuel timing, boost levels, and the amount of fuel injection.

This isn’t something they take lightly either - there is a ton of research, development, and testing that every tuning company will spend countless hours perfecting before the tune ever reaches the public market. Even after the tune is perfected and available for purchase there will be constant updates, tweaks, and changes to the tune as technology changes and glitches and bugs are found. As of the last few years, most companies are shooting for smoke-free high-efficiency horsepower without blowing everyone’s engines and transmissions to pieces. 


EZ-Lynk Auto Agent


The big three tuners we use at the shop are EZ-Lynk, MM3, and EFI Live. Each one comes empty and requires you to pair it with a custom tuning company of your choice, we use these because they tend to be much more refined than a canned tune package that comes with a generic tune off the shelf. You’ll find custom tuning offers better driveability, more efficient power, and endless adjustability for when you decide to upgrade your turbo, install bigger injectors or get a built transmission. 


BD Diesel Turbo Upgrade 6.7L Cummins

A Bigger Turbo is Always a Good Idea.

These devices also offer data-logging, if you notice your truck acting weird under certain conditions that are difficult to replicate, data-logging can save you a lot of time and headaches trying to replicate the issue when you get to a shop. These devices allow you to save your ECM’s information when these issues happen and you can then send these to your tuning company so they can see exactly what’s going on and make a tweak in the tuning if need be. If you’ve ever had a sporadic problem with your truck you’ll understand how much of a lifesaver this can be.

Custom Tuning from one company will perform similarly whether you choose to load it through an EZ-Lynk, EFI Live, or an MM3. However, each device will operate differently and offer different features to the end-user.

EFI Live

EFI Live is a fantastic custom tuning platform, however, the Autocal or Flashscan device that you use to load it into the truck with does not give you any type of display to monitor your truck with. It simply allows you to take a stock truck and flash the ECM with new tune files, it’s a great option for those that are just looking for a delete tune, tow tune, or a few different power options to increase the drivability. EFI Live can be combined with a switch to offer 5 different power levels for the 2008-2012 Cummins and 4 power levels for the 13-19+ Cummins. We use EFI Live every day in-house as it’s a very affordable way for us to flash a customers truck with top of the line custom tuning.


EFI Live Auto Cal - 6.7L Cummins


The MM3 Tuner is an incredible interface between you and your ECM and acts as a customizable display to monitor your truck. The MM3 gives you the option of real-time tuning where you can change parameters while the truck is running and shift on the fly power levels are available directly through the display and no additional switch is required. Once you purchase your MM3 you’ll need to plug it into your truck to read to the stock ECM file, that file is then emailed to the tuner of your choice and modified from there. We then send you the tune file back for you to load onto the SD card and you’re ready to flash your truck! The main dashboard of the MM3 is a great monitor for watching your ECM parameters and can be paired with a pyrometer add-on to watch your Exhaust Gas Temps (EGT’s).

Smarty MM3 Tuner


The EZ-Lynk platform is the latest device to hit the market and offers Cloud Based Tuning where you build an account and are linked directly to the tuning company of your choice. You download an app on your phone (iOS or Android), then connect to the EZ-Lynk through Wifi. The EZ-Lynk app will allow you to access your tuners complete library of tune files available for your truck, you simply download the file you want off the cloud and load it into your truck very quickly from your phone. Once your truck is tuned, you can head back to the dashboard in the app and use your device to monitor or datalog. 

The EZ-Lynk will require a secondary switch to use the Driver Selectable Tuning options which allow you to switch between tune files on the go.

One of our favorite features of the EZ-Lynk app is the integrated chat feature. It allows you to hit a button and contact your tuning company or technician right through the app. This allows you to update your tunes, send diagnostics, or share data-logs without having to make a phone call, book an appointment, or send an email. If you’re traveling and your truck starts to act up, your tuner can see the issue, read your data-logs, and send an update to you from anywhere. Similarly, whenever they release an update for your truck, you’ll get a notification on your device and the new tune will be available for download.

Updating an EZ-Lynk Auto Agent with PPEI Tuning

Flashing is easy as pulling out your phone and choosing your new tune.


For you 2010+ guys with the 68RFE automatic transmission, an additional transmission tuning upgrade can be purchased along with your ECM tuning. This involves increasing your line pressure for crisper shifts, better torque converter lockup control, and less gear hunting. This not only significantly increases the driveability, but it also will increase the life of this feared transmission. We always will highly recommend the transmission tuning on the 2010+ Cummins as it is well worth the money to give you the peace of mind knowing your transmission is safe.

Whether you choose and EZ-Lynk, MM3, or EFI Live they all work great and offer what we have found to be the best tuning options for the 6.7L Cummins platform. When combined with amazing companies like CCS, PPEI, and Proven Diesel you get the best device paired with the best tuning on the market.

We know, there are hundreds of tuning companies, tuning platforms, and tuning options for your truck on the market at any given point and I’m sure they’re probably great, however, we tend to stick to EFI Live, EZ-Lynk, and MM3 with either PPEI, Proven Diesel, or CCS tuning. We do this because at Dirty we only sell what we know, what we’ve tried, and what we use on our personal trucks. We have built a relationship and trust these guys so we feel confident standing behind their products. Simple as that. 

I hope this answered some questions about all the options available for tuning your 6.7L Cummins. If not, reach out and ask away. We’re always here to help. 

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Questions? Thoughts? Let us know below!