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What does an EGR delete do on a Duramax?


The LLY Duramax EGR (Exhaust Gas Recirculation) System is what primarily contributes to the black smoke you see in LLY trucks. The LLY EGR system also causes severe tuning issues with programmers and tuners. It has been proven after several years of research that deleting the LLY EGR system is an easy task; it will cause no harm to your engine, and will actually result in better fuel economy due to lessened load on the motor when tuning is completed for this purpose.

What do I need to De-EGR my LLY?

The LLY requires a complete kit including A high flow water pump, valve cover breathers (moving from PCV style cap to ported valve cover breather), LLY / LB7 High-Pressure Oil Pump, LLY EGR Delete Block off Plates, New head bolts for the LLY, and an LLY EGR Deletion wiring harness.


What are the Benefits of De-EGR’ing my LLY?

– Removes black smoke from LLY trucks

– Increased Towing Capacity due to lessened engine load/tune adjustments being necessary to accommodate this change in performance attributes.

– Decreased Depreciation on your truck because you can now your Tow/Haul feature to haul more weight.

– LLY EGR Delete Kit Installation is a simple task that only requires the truck to be on a lift and access to basic hand tools such as wrenches, a ratchet set, etc.

What other Deletion kits should I consider? (for LLY trucks)

– Aftermarket Intake system: LLY intake elbows and LLY intake snorkels delete also contribute to black smoke production in LLY vehicles; therefore it’s recommended to replace these items with Doug Thorley Headers LLY Intake Elbows or LLY Intakes Snorkel delete (depending upon your model year). The Undamax intake elbow by Doug Theory does not produce any black smoke because there are no internal restrictions with this high flow elbow.

– LLY LB7 EGR Deletion LLY/LB7 Intake Elbow LLY/LB7 Headbolt LLY Exhaust Manifold Gasket LY5 Head gaskets LLY EGR Delete Block off the plate

– Inline Fuel Filter Delete Kit: This inline fuel filter delete kit by Undamax is a beneficial future upgrade that you can perform on your LLY Duramax to ensure your engine stays running at peak performance for the long haul! The construction of the LLY fuel pump and inline fuel filter are less than ideal which causes clogging of the filters over a short amount of time. Simply replacing these items will your truck’s ability to go through LLY EGR Delete Kit. The LLY / LB7 LLY/LB7 Fuel Filter LLY/LB7 LLY Diesel Fuel Pump can be purchased separately or together for added savings.

– Head studs: LLY Duramax head bolts fail over time due to the high cylinder pressure produced by the diesel engine; therefore it’s recommended that you purchase an LLY LLY Head Gasket Set at the same time that you purchase the LLY Duramax EGR Delete kit to ensure your engine stays in one piece!

– Aftermarket DPF Delete Kit: Your stock exhaust manifolds contain restrictive catalytic converters which are required on all vehicles with federal emission standards; however these parts are known to fail at high rates after the LLY EGR Delete Kit is installed. Aftermarket LLY LLY Diesel Catalytic Converter LLY LLY LLY Diesel DPF Delete Kit allows you to remove these items for increased performance; however, you will no longer be able to pass your state’s emissions testing.

– Air Intake / Snorkel Delete: LLY motors are known to ingest water into their motors when driving through deep puddles or crossing rivers, etc; therefore it’s recommended that you delete the LLY Highway Max Intake Elbow and replace it with a Doug Thorley LLY/LB7 LGH Undamax Intake elbow (depending upon your vehicle model year) which has no internal water ingestion restrictions. LLY Undamax Intake Elbow LLY Highway Max Intake elbow LLY

– Air Flow Booster Delete: The post-2010 LBZ and 2011+ LML Duramax motors (like the one in your truck) utilize an Air Flow Booster which forces outside air directly into the intake system upstream of the turbocharger; therefore it’s recommended that you delete this component for increased performance and fuel economy.

– High-Pressure Oil Pump: This upgrade is designed to decrease operating temperatures in your engine and increase horsepower throughout the power band; however, due to these changes, we recommend performing a Cold Weather Pack when installing this part on LBZ/ LML LLY QSV-R Pressure Booster.

– ECM Programmer: The stock LLY Duramax ECM will limit your truck’s performance potential; therefore we suggest checking out an Edge Juice w/ Attitude CTS2. This handheld device reprograms the diesel tuning to extract every bit of horsepower and torque from your engine! LLY LLY Diesel Tuner LLY Fuel Controller Truck

– External Bypass Oil Filter: This is a required upgrade that we highly recommend for all LLY trucks used in high mileage, heavy-duty work applications. The factory oil filter and cooler restrict flow too often and cause premature engine failure; therefore we recommend the Undamax bypass system to ensure your LLY Duramax can perform at peak levels during extreme use.

– EGR Cooler Delete: The stock EGR cooler is very restrictive on LML/LBL/LBZ Duramax engines which causes poor fuel economy and horsepower loss; therefore we suggest deleting the EGR cooler as an important part of your / LB7 / LBZ LLY Diesel EGR Delete kit.

– Aftermarket Turbo’s: The stock LLY Duramax turbochargers have routinely been shown to fail at around 60,000 miles due to excess heat and exhaust gas recirculation caused by the EGR system; therefore we suggest upgrading your turbos to a larger unit with any of our LLY Turbo Upgrades depending upon your horsepower goals.

– Injection Pump Gears: We’ve noticed that most LLY / LBZ / LML injection pump gears fail from heavy-duty use over time; therefore it’s highly recommended that you purchase a spare set of these injection pump gears when performing an LLY EGR Delete kit on any LLY Diesel EGR Delete kit.

– Turbo Studs: These simple studs are designed to replace the factory bolts which hold your turbos in place; therefore we suggest purchasing a set of these when performing an LLY EGR Delete kit on any LLY

– High-Temperature Coating: It’s not uncommon for stock oil cooler lines to fail when performing an upgrade such as the Doug Thorley Undamax Intake Elbow or Cold Weather Pack with an Air Flow Booster. If one of your oil coolant lines is faulty, this will cause damage to your engine! Therefore it’s recommended that you install a high-temperature coating on all LLY Undamax Intake Elbow LLY

What problems do LLY Duramax have?

– EGR Cooler Restriction: The factory EGR cooler is very small and restrictive which causes poor fuel economy, decreased horsepower, and often premature failure.

– Turbo Failure: The stock turbochargers are undersized for the power output of the engine; therefore they do not receive adequate cooling when performing at maximum power levels which causes them to fail prematurely.

– High-Pressure Oil Pump Restriction: This component restricts oil flow to vital components when operating above 4000 RPM’s which reduces horsepower and fuel economy throughout the powerband.

– Fuel Filter Restriction: This part has multiple flow restrictions built into it that cause reduced fuel economy and horsepower.

– Head Stud Stretch: When the engine is new, the factory head bolts are torqued to 75ft/lbs; however after this mileage, they often stretch causing a loss of compression and horsepower.

Which Duramax is better, the LB7 or LLY?

The simple answer would be “both.” The newest version of this engine family offers more power and efficiency with lower emissions. However, you’ll have to decide for yourself which one fits your driving needs most importantly because they both come equipped differently from factory settings depending on what kind of truck it’s in!

How long do Duramax LLY injectors last?

The Duramax LLY injectors are designed for long life. They should last between 150,000 and 200K miles most of the time with regular maintenance care in good condition!


The LLY EGR delete kit is an excellent option if you want to eliminate the possibility of your car engine shutting down due to a faulty sensor. If your vehicle’s check engine light has been on for more than three months, it may be time to consider buying one of these kits and performing the repair yourself.

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