Mercedes-Benz E-Class OM651 Injectors

Mercedes-Benz E-Class OM651 Overview

The Mercedes-Benz E-Class with the OM651 2.1L CDI engine was produced between 2009 and 2016. This vehicle uses Delphi common rail diesel injectors (primary part number A6510704987) operating at fuel pressures up to 2000 bar. The OM651 engine in the Mercedes-Benz E-Class produces 100–150 kW (136–204 PS) and 300–500 Nm of torque. When replacing injectors on the Mercedes-Benz E-Class OM651, always use new copper sealing washers and torque to manufacturer specifications. Each injector should be coded to the ECU after fitting.

Compatible Injectors

Common Injector Problems in Mercedes-Benz E-Class

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  Rough idle and engine vibration — Worn injector nozzles cause uneven fuel spray, leading to rough idle at low RPM. Most noticeable when the engine is cold.
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  Excessive exhaust smoke — Black or blue-grey smoke on acceleration indicates poor fuel atomisation. This is often caused by carbon buildup on the injector nozzle tip.
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  Poor fuel economy — A worn or leaking injector delivers incorrect fuel quantities, reducing efficiency by 10–20% in severe cases.
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  Engine misfire under load — Intermittent misfires during acceleration suggest one or more injectors are failing to deliver the correct fuel pressure.
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  Difficult cold starting — Degraded injector nozzles struggle to atomise fuel at lower cranking pressures, causing extended crank times in cold weather.

Other OM651 Vehicles

Related Pages

Delphi 2.1L CDI — browse compatible engines, vehicles, and injectors