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Thoroughbred Sku #: FPE-LML-CP3-WP
Year/Make/Model: {{year}} {{make.Name}} {{model.Name}} Edit
$2,095.00
2011 - 2016 Chevy Silverado 2500
2011 - 2016 Chevy Silverado 3500
2011 - 2016 GMC Sierra 2500
2011 - 2016 GMC Sierra 3500
Product Name: Fleece CP3 Conversion Kit with CP3 for 2011-2016 LML Duramax Manufacturer: Fleece Manufacturer Part #: FPE-LML-CP3-WP Thoroughbred Diesel Part #: FPE-LML-CP3-WP Fitment Notes: 2011-2016 LML Duramax
Convert your LML's fuel system from a CP4 to a CP3
Improve your LML Duramax's reliability and fueling capability with a CP3 conversion. Since its introduction, the CP4 has proven to be less reliable and less capable than the CP3 used in previous Duramax platforms. Failures of the CP4 are extremely costly and require replacement of the entire fuel system. Avoid a costly failure down the road and convert your CP4 to a CP3 with our complete, no tuning required kit for the 2011-2016 LML Duramax platform. Our kit provides you with OEM fit-and-finish features like a brand new Bosch CP3, Fleece exclusive molded hoses for the fuel feed and return, high flow CP3 fuel fittings, and our valley feed line to support aftermarket lift pump applications.
* Protected under US Patent D1023736 and Patents Pending
CARB EO# D-834-1
SEMA CERT: SC-FLC01-0013
Fleece CP3 Conversion Hardware Kit Features:
Kit Contents:
What LML CP3 Conversion Kit is right for you?
We've got a number of choices when it comes to CP3 conversion kits, let us help you in the proper selection:
FPE-LML-CP3-NP: Our "No Pump" kit for the LML CP3 conversion gives you the option to select your own CP3 pump for your application. Our kit provides you with all of the hardware you need to adapt a LBZ/LMM based Bosch CP3 to your 2011-2016 LML Duramax.
FPE-LML-CP3-WP: Our "With Pump" kit for the LML CP3 conversion gives you a brand new LBZ/LMM Bosch CP3 along with all of the hardware you need to convert your CP4 equipped Duramax to a CP3. This kit is designed for use with or without a low pressure lift pump. For optimal performance, if the truck is equipped with a lift pump, the feed pressure to the CP3 should not exceed 11 psi when utilizing this kit.
FPE-LML-CP3-10: Our Heavy Duty kit for the LML CP3 conversion features a brand new LBZ/LMM Bosch CP3 equipped with a Fleece Performance 10mm stroker cam along with all of the hardware you need to convert your CP4 equipped Duramax to a CP3. This kit is designed for use with or without a low pressure lift pump. For optimal performance, if the truck is equipped with a lift pump, the feed pressure to the CP3 should not exceed 2 psi. Engine surging may be induced by the additional fuel pressure of a lift pump operating at pressures over 2 psi. If you are intending to combine this kit with a Fleece PowerFlo lift pump, contact us for a lower rate spring for your pump to accommodate operation with this kit. For higher lift pump pressures, FCA table values will require adjustment.
No core on this item.
A bad Bosch CP3 fuel pump causes low rail pressure, hard starting, and poor power. You can test it by checking actual versus commanded pressure with a scan tool or by measuring the return flow volume. Common Signs:
Testing Methods:
An LML Fleece CP3 conversion kit replaces the failure-prone factory CP4 fuel injection pump with a more durable, mechanical three-piston CP3 pump. Key benefits include permanent CP4 failure prevention, stable high-pressure fuel delivery, and better contaminant tolerance. Here's what the Fleece kit includes:
No, the Bosch CP3 pump does not fail like the notorious CP4 pump. The CP3 is widely considered one of the most reliable high-pressure fuel injection pumps ever built for diesel engines, whereas the CP4 has a well-documented history of catastrophic, expensive failures. Here's a nice quick video on what the Fleece kit includes:
Whether you need a tune after a CP3 fuel pump conversion depends entirely on the specific conversion kit you buy. Many modern kits feature calibrated regulators or drop-in designs that require no tuning and run safely on factory settings, while standard kits explicitly require a custom ECM recalibration. What the Fleece kit includes:
A Fleece CP3 pump conversion on an LML Duramax typically takes 10 to 16 hours of labor for a professional shop or an experienced DIYer. If you are working at home in your driveway, it often spans a full weekend or 2 to 3 days to account for breaks, stubborn components, and potential coolant or fuel line handling. Here's what comes in the kit:
TOOLS REQUIRED: ½” fuel disconnect, 3/8” fuel disconnect, 3/8” ratchet, metric socket set, metric wrench set, 1 1/16” socket, 27mm socket, 3/8” socket extensions, fan clutch removal tool, 3/8” and ½” torque wrench, ¼” and 5/16” nut driver, pliers, 7/8” wrench, 15/16” wrench, pry bar, hose pick and Dorman 904-484 or CTA 3477 fuel line quick disconnect tool. Watch this step-by-step vidoe and do it yourself!
Fleece, S&S Diesel Motorsport, Industrial Injection, BD Diesel or Thoroughbred Diesel make excellent CP3 Conversion Kits for 2011-2016 LML Duramax.
No, CP3 fuel pumps do not fail like CP4 pumps. The older Bosch CP3 is legendary for its long life and high durability, often lasting over 200,000 miles. In contrast, the newer Bosch CP4 has a high profile for sudden, catastrophic self-destruction.
A CP3 pump conversion on an LML Duramax typically takes 10 to 16 hours of labor for a professional shop or an experienced DIYer. If you are working at home in your driveway, it often spans a full weekend or 2 to 3 days to account for breaks, stubborn components, and potential coolant or fuel line handling.
Yes, you can convert a 2011–2016 LML Duramax fuel system from a CP4 to a more reliable CP3 pump and require no custom tuning or modifications. Do it yourself and save money!
The best CP3 conversion kits for a 2011–2016 LML Duramax engine are offered by Fleece Performance, S&S Diesel Motorsport and Thoroughbred Diesel Fuel System Contamination Kits. These kits replace the failure-prone factory CP4 pump with a reliable Bosch CP3 and feature CARB-compliant options that require no custom tuning.
Yes, the LML CP3 conversion is widely considered worth it because it replaces the failure-prone Bosch CP4.2 high-pressure fuel pump with the much more durable and forgiving CP3 pump. If a CP4 pump fails ("grenades"), it contaminates the entire fuel system with metal shavings, resulting in a catastrophic repair bill.
Yes
Please call in to speak with someone on our Tech Line.
1 Year Limited Parts Warranty
No, it must be a LBZ/LMM.
No bolt and go. Do not exceed 11 psi.
It will operate at the commanded levels.
No other gaskets required
The fuel can be adjusted only through tuning.
It is not required, but a lift pump is always a good upgrade.
No
Not with this kit:
https://www.thoroughbreddiesel.com/2015-gmc-sierra-2500/fleece-cp3-conversion-kit/?HideOptionsEditButton=True
Emissions Compliant CP3 Conversion Kit DOES NOT REQUIRE TUNING.