A 6.7 Cummins delete kit removes emissions equipment and requires a tuner to reprogram your engine

A 6.7 Cummins delete kit removes the diesel particulate filter (DPF), selective catalytic reduction (SCR) system, and exhaust gas recirculation (EGR) cooler from your engine. The tuner is the software that tells your engine computer to stop looking for these parts and to run without them. Without the tuner, your truck will throw error codes and go into limp mode. The kit itself is the physical hardware; the tuner is what makes the truck drivable after removal.

This modification is legal to own and install on your own property, but it is illegal to drive on public roads in all 50 states. The EPA prohibits removing or disabling emissions equipment on any vehicle model year 2007 and newer. Selling a delete kit with the intent that it be used on a road vehicle is also illegal. Many shops and tuner manufacturers have faced federal fines and criminal charges for selling these kits.

Key Takeaways

  • A delete kit removes three emissions systems (DPF, SCR, EGR cooler) and a tuner reprograms the engine to run without them.
  • Deleting emissions equipment is illegal on public roads and can result in EPA fines, failed inspections, and liability if your truck causes an accident.
  • The physical kit costs between $800 and $2,500 depending on brand and whether you do the labor yourself or pay a shop.
  • Tuners range from $400 to $1,200 and must be compatible with your specific truck year, engine code, and transmission.
  • Deleted trucks often see better fuel economy and more power, but lose warranty coverage and may have resale complications.

What each part of a delete kit removes and why

The diesel particulate filter (DPF) traps soot from the exhaust. It regenerates by burning off the trapped soot at high temperatures, a process that happens automatically while you drive or during a parked regen cycle. Many owners delete it because regens reduce fuel economy temporarily, DPF clogs can cause limp mode, and cleaning or replacing a DPF costs $1,500 to $3,000.

The selective catalytic reduction (SCR) system injects diesel exhaust fluid (DEF) into the exhaust stream to convert nitrogen oxides into nitrogen and water. It requires you to refill DEF every 5,000 to 15,000 miles depending on driving. Owners delete it to avoid DEF costs, DEF tank failures, and the weight penalty of carrying extra fluid.

The exhaust gas recirculation (EGR) cooler cools exhaust gases before they re-enter the engine to lower combustion temperatures and reduce emissions. 6.7 Cummins EGR coolers are known to fail and leak coolant into the oil, which can destroy the engine. Deleting it removes this failure point, though the engine will run hotter without it.

How a tuner reprograms your engine after deletion

A tuner is a handheld device or software interface that connects to your truck's on-board diagnostic (OBD) port, usually located under the steering wheel. The tuner reads your engine's current programming, modifies the code to remove emissions system references, and writes the new code back to the engine control module (ECM). This process takes 30 minutes to two hours depending on the tuner brand.

Once the tune is loaded, your truck will no longer monitor the DPF for regeneration, will not inject DEF, and will not look for EGR cooler operation. The engine runs on a modified fuel map and timing curve optimized for the deleted configuration. Some tuners allow you to switch between a stock tune and a delete tune, though this is rare on 6.7 Cummins because the hardware is physically removed.

Popular tuner brands for 6.7 Cummins include Edge, Smarty, H&S, and Bully Dog, though availability and legality vary by region. Many tuner companies have stopped selling delete tunes outright and now sell "performance" or "economy" tunes that do not explicitly mention deletion. You will need to research which tuners are still actively supporting 6.7 Cummins and which ones match your truck's year and transmission type.

Cost breakdown for a complete delete kit and tuner setup

A complete delete kit (DPF, SCR, EGR cooler, pipes, and gaskets) costs between $800 and $2,500 depending on brand and whether you buy individual components or a bundled kit. Popular aftermarket brands include MBRP, Flo Pro, and Wicked Diesel. Labor at a diesel shop typically runs $1,500 to $3,000 if you do not do the work yourself, though some shops refuse to perform deletes due to legal liability.

A tuner costs $400 to $1,200 depending on the brand and whether it is a handheld device you own permanently or a one-time mail-in tune. Handheld tuners like Edge and Smarty let you adjust settings yourself; mail-in services like Bully Dog send you a device, you load the tune, and you return it. Some tuners charge extra for multiple tunes or for switching between tunes.

Total out-of-pocket cost ranges from $1,200 to $4,700 if you pay a shop to do the work, or $1,200 to $3,700 if you install the kit yourself and buy a tuner. This does not include potential costs for fixing problems that arise, such as oil cooler failures or turbo issues that some deleted trucks experience.

Performance and fuel economy changes after deletion

Most owners report 3 to 8 miles per gallon improvement in fuel economy after deletion, especially during highway driving. The DPF regeneration cycle, which forces the engine to run rich and hot, is eliminated. DEF injection no longer consumes fuel. The engine also runs cooler overall because it is not fighting emissions equipment, which reduces parasitic load.

Horsepower and torque gains vary widely. A stock 6.7 Cummins makes roughly 370 horsepower and 850 pound-feet of torque. After deletion and a performance tune, owners report 50 to 100 additional horsepower and 100 to 150 additional pound-feet of torque, though these numbers depend heavily on the tuner's calibration and whether other modifications are present. Some tuners prioritize economy over power; others do the opposite.

Deleted trucks also tend to run cooler because the EGR cooler is no longer recirculating hot exhaust into the engine. This can extend engine life in theory, though long-term data on deleted 6.7 engines is limited because the engine is still relatively new. Some owners report increased turbo boost and faster spool-up due to less backpressure in the exhaust.

Legal consequences and warranty loss

Driving a deleted truck on public roads violates the Clean Air Act. The EPA can fine vehicle owners up to $37,500 per violation. States can also impose fines during emissions testing or roadside inspections. Some states have begun cracking down on deleted trucks, particularly in California, Colorado, and the Northeast, where air quality standards are stricter.

Your truck's manufacturer warranty is void the moment the DPF is physically removed. Dodge and Cummins will not cover any engine, transmission, or emissions-related repairs once deletion is detected. If your engine fails for any reason after deletion, you will pay for repairs out of pocket, which can easily exceed $5,000 to $15,000 for major work.

Resale value is complicated. Some buyers specifically seek deleted trucks and will pay a premium. Others will not buy a deleted truck at all due to warranty loss and legal risk. You are required to disclose the deletion to a buyer, and some states require the truck to be re-tuned to stock before sale. If you plan to sell the truck later, deletion may make it harder to move.

Common problems and failure points in deleted trucks

Deleted 6.7 Cummins trucks sometimes develop oil cooler leaks because the engine runs hotter without the EGR cooler. The oil cooler was not designed for sustained high temperatures, and coolant can leak into the oil. This requires replacing the oil cooler, which costs $800 to $1,500 in labor and parts.

Some deleted trucks experience turbo lag or boost creep because the tuner's fuel map was not optimized for the specific truck's configuration. This is usually fixable with a tune adjustment, but it requires going back to the tuner or a diesel shop. A few owners report increased black smoke under hard acceleration, which indicates the tune is running too rich.

Deleted trucks can also fail state emissions testing if your state still requires it. Some states have stopped testing diesel trucks, but others have not. If you live in a state that tests, a deleted truck will fail and you will be unable to register it legally. You would then need to have the truck re-tuned to stock, which some tuners can do but others cannot.

Frequently Asked Questions

Can I switch back to a stock tune after deletion?

Only if your tuner supports it and you still have the original engine code. Some tuners like Smarty allow you to load a stock tune back onto the ECM. However, the physical DPF, SCR, and EGR cooler are still removed from the truck, so the stock tune will throw error codes and put the truck in limp mode. You would need to reinstall the emissions equipment to run stock again, which defeats the purpose of deleting.

Will a deleted truck pass a state emissions test?

No. A deleted truck will fail any state emissions test because the DPF and SCR are physically removed and the tuner disables monitoring for them. Some states no longer test diesel trucks, but if your state does, you cannot legally register a deleted truck. You would need to have the emissions equipment reinstalled and the truck re-tuned to stock before testing.

How long does it take to install a delete kit?

Installation typically takes 8 to 16 hours depending on the kit, your truck's year, and whether you are doing it yourself or paying a shop. The DPF removal is usually the longest part because it is bolted to the exhaust manifold and can be corroded. The tuning process itself takes 30 minutes to two hours once the hardware is installed.

Do I need to change my oil more often after deletion?

Not necessarily. Some deleted trucks run cleaner because there is no DPF ash entering the oil, which can actually extend oil life. However, deleted trucks run hotter, which can degrade oil faster. Many owners stick to their normal oil change interval or shorten it by 1,000 to 2,000 miles as a precaution. Check your tuner's recommendations.

What happens if I get pulled over in a deleted truck?

A police officer cannot tell your truck is deleted just by looking at it. However, if you are pulled over for a traffic violation and the officer runs your vehicle identification number (VIN), some states flag deleted trucks in their system. If caught, you could face fines and be ordered to restore the truck to stock. The risk varies by state and local enforcement.