2011-2016 GM/CHEVROLET 6.6L DURAMAX LML LGH REGULATED FUEL LINE ASSEMBLY ( BRAND NEW HIGH QUALITY AFTERMARKET)
If your Duramax (LML or LGH model) won't start, one of the first things to check is the fuel injector return line pressure. This pressure must be at least 3 bar (44 PSI) for proper operation. If the pressure is low and there are no visible leaks in the return hose assembly, the most likely culprit is the return line pressure regulator, which is integrated into the hose assembly.
The piezoelectric injectors used in these engines require sufficient backpressure to operate correctly. The return line pressure regulator is designed to maintain pressure between 4 and 11 bar (58–160 PSI). A weak or failing regulator often results in hard starting or no-start conditions.
Ensure precise fuel pressure regulation and reliable return flow with this Regulated Fuel Return Line Assembly for 2011–2016 GM/Chevrolet 6.6L Duramax diesel engines. Designed specifically for LML and LGH applications, this OE-style return line system controls excess fuel from the injectors, helping maintain fuel system balance and performance.
If your truck is experiencing hard starts, excessive fuel rail pressure, or erratic idling, the return line assembly could be compromised. This complete assembly restores factory fuel flow dynamics and eliminates common leaks or restrictions caused by degraded rubber lines or damaged connectors.
What’s Included in the Kit:
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Pre-assembled regulated fuel return line
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Fuel pressure regulator fitting
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Integrated quick-connect fittings
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Return hose sections with proper bends
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Brackets or clips
Features & Benefits:
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Exact Fit for LML & LGH Engines: Precision-designed to OEM specs for plug-and-play installation
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Restores Fuel Pressure Regulation: Maintains proper return flow for injector performance
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Fixes Fuel Rail Pressure Issues: Addresses codes like P0088 and P0090 related to fuel overpressure
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Durable Materials: Heat- and diesel-resistant hose construction with molded connectors
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Improved Cold Start & Idle: Helps resolve poor starting or unstable idle conditions
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Direct Replacement: No cutting, splicing, or retrofitting required
Compatibility:
Fits the following GM/Chevrolet Duramax 6.6L Diesel Models:
• 2011–2016 Silverado & Sierra 2500HD / 3500HD (LML)
• 2011–2016 Savana & Express Vans (LGH)
• 2011–2016 Chassis Cab models equipped with LML or LGH engines
For use on trucks with the factory CP4 high-pressure fuel pump system.
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California Proposition 65 Warning:
This product contains chemicals known to the State of California to cause cancer and birth defects or other reproductive harm. For more information, visit www.P65Warnings.ca.gov.
Diagnostic Trouble Code (DTC) P0090 – Fuel Pressure Regulator Control Circuit
Meaning:
P0090 relates to an electrical issue in the circuit that controls the Fuel Pressure Regulator (FPR), which is responsible for regulating high-pressure fuel into the rail.
Common Causes:
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Faulty Fuel Pressure Regulator (MProp)
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Damaged wiring or connector (short/open)
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Failed ECM or control driver
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Corroded connector pins at FPR
Symptoms:
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Hard start or no start
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Surging idle
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Reduced engine power mode
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Poor acceleration
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CEL illuminated
Application to Duramax Engines:
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P0088 is especially common in LML and LGH models with CP4 pumps when the pressure regulator sticks or fuel return line pressure is excessive.
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P0090 is more of a control/electrical issue and can occur across LLY, LBZ, LMM, LML models when there’s damage to the fuel pressure regulator circuit or the MProp itself fails.
