How to Delete a 6.7 Cummins: Complete Step-by-Step Guide 2026

Here's the thing — the 6.7 Cummins is a legitimately outstanding engine. The emissions hardware bolted to it? That's a different story.

• DPF (Diesel Particulate Filter) traps soot and forces active regeneration cycles that burn fuel, spike Exhaust Gas Temperatures (EGTs), and interrupt towing sessions at the worst possible moments.
• EGR recirculates hot exhaust gases back into the intake, depositing carbon on the intake manifold, valves, and cooler — eventually causing coolant leaks and power loss.
• DEF/SCR system adds a Selective Catalytic Reduction (SCR) layer that requires constant DEF fluid top-offs and introduces another failure point with its own sensors, pumps, and injectors.

According to SpeedwayMedia's 2026 guide, owners running a full delete report 2–4 MPG improvement (roughly 10–20% relative to baseline)s and 100–200 HP gains alongside the elimination of regen cycles entirely ^[1]. That's not just a performance upgrade — it's a reliability upgrade. Fewer systems means fewer things to fail on a work truck pulling 20,000 lbs every day.

This is where a lot of DIY builds go sideways. Guys buy a delete pipe, skip the EGR, and wonder why they're pulling P0401 codes two weeks later. A proper full delete needs every piece working together.

The complete parts list:

1. DPF/CAT Delete Pipe — replaces the Diesel Particulate Filter and catalytic converter section; typically 4" diameter
2. EGR Delete Kit — includes block-off plates and cooler bypass hardware to seal the EGR circuit
3. DEF/SCR Bypass Fittings — eliminates the DEF injection system and SCR catalyst requirement
4. CCV Reroute Kit — redirects crankcase vapors away from the intake tract
5. Delete Tuner — either a handheld OBD-II device or bench flash service with VIN-specific tune files

The easiest way to make sure you have everything? A full delete bundle purpose-built for your year range. The Ram Cummins 6.7 Full Delete Bundle from The Diesel Dudes includes all of the above in one box, pre-matched for your truck's ECM ^[1].

Prep work separates a clean install from a frustrating one. Gather everything before the truck goes up on jack stands.

Tool checklist:

• 10-amp battery charger — keeps voltage stable during ECM flashing; low voltage mid-flash can brick a tune
• OBD-II scanner — for clearing DTCs before and after the tune install
• Socket set — 3/8" and 1/2" drive; metric and standard; deep sockets for exhaust studs
• Torque wrench — exhaust flanges and EGR fittings need proper torque
• Coolant drain pan — the EGR cooler holds coolant; it will come out when you disconnect hoses
• Penetrating oil — soak exhaust bolts the night before; seized hardware on high-mileage trucks is the number one time killer
• Zip ties and heat wrap — for routing the CCV lines cleanly away from heat sources

Also verify your truck's VIN and model year before ordering anything. The 2022–2024 Ram 6.7L Cummins uses a different ECM calibration than 2019–2021 trucks — tune files are not interchangeable ^[1].

Let's break it down by year range so there's no confusion at the parts counter.

SpeedwayMedia's 2026 guide confirms that 2026-era ECMs require VIN-specific calibrations — generic tune files pulled from older platforms will not function correctly on the latest trucks ^[1].

This is the bulk of your under-truck time. Budget 2–3 hours for this phase on a first attempt.

1. Lift and support the truck — jack stands under the frame; never trust a floor jack alone
2. Disconnect the negative battery terminal — eliminates any risk to the ECM during sensor disconnects
3. Spray all exhaust flange bolts with penetrating oil 30 minutes before wrenching; seized studs on high-heat hardware are common
4. Unplug all sensors — DPF differential pressure sensor, inlet/outlet temp sensors, and NOx sensor harness connectors before unbolting anything
5. Unbolt the DPF/DOC/SCR assembly from the downpipe flange forward and the tailpipe rearward; have a helper support the weight — these canisters are heavy
6. Remove the DEF injector line from the SCR inlet; cap the DEF pump outlet to prevent fluid spillage
7. Install the delete pipe — bolt the high-flow 4" pipe into the existing flanges, transfer sensors to the new bungs, and torque flange bolts evenly

Per The Diesel Dudes Technical Team's install documentation , a clean DPF removal on a 2022–2024 Ram typically takes 90–120 minutes with the right tools staged ahead of time.

The EGR system on the 6.7 Cummins runs hot exhaust gas through a coolant-fed cooler and back into the intake. Carbon buildup and cooler failures are the inevitable result. Here's how to remove it cleanly.

1. Drain the coolant — the EGR cooler is part of the cooling circuit; you'll lose coolant when you disconnect hoses, so drain first
2. Disconnect EGR cooler hoses — two coolant lines feed the cooler; have rags ready
3. Unbolt the EGR cooler from its mounting bracket and the exhaust crossover pipe; set it aside
4. Remove the EGR valve from the intake manifold — typically 4–6 bolts depending on model year
5. Install block-off plates at both the intake manifold port and the exhaust-side port; use new gaskets for a clean seal
6. Install the coolant bypass pipe — routes coolant through the circuit the EGR cooler previously occupied, maintaining proper coolant flow
7. Cap all vacuum lines that previously actuated the EGR valve

SpeedwayMedia's 2026 guide notes that skipping the EGR delete while only running a DPF delete pipe results in persistent P0401 fault codes and ongoing carbon accumulation ^[1]. Do both together.

The tune is what tells the ECM the emissions hardware is gone. Skip this step and your truck will run in limp mode the moment it detects missing sensors and zero DPF backpressure.

1. Connect battery charger at 10 amps — voltage drop during a flash corrupts tune files; this is non-negotiable
2. Plug tuner into OBD-II port under the driver-side dash; turn key to RUN position but do not start the engine
3. Select ECM Recovery on the tuner menu — this backs up your stock ECM calibration before writing anything new
4. Confirm VIN match on the tuner screen — the device reads your truck's VIN and cross-references it with the loaded tune file
5. Select Program Custom File and confirm; the flash writes in approximately 10–15 minutes
6. Wait for completion signal — green light or confirmation screen; do not disconnect power mid-flash
7. Clear all DTCs using your OBD-II scanner immediately after flashing
8. Start the engine and let it idle 30 seconds; monitor for any new fault codes

The Diesel Dudes Technical Team's video documentation shows this process clearly — the ECM accepts the file, the engine idles cleanly, and emission-related codes clear immediately.

Let's talk real-world numbers. These aren't theoretical — they reflect what owners consistently report after running a full delete bundle with proper ECM tuning.

SpeedwayMedia's 2026 guide corroborates these figures across multiple owner reports ^[1]. The throttle response improvement alone — no more sluggishness from DPF backpressure — is something you notice within the first mile of the test drive.