Isuzu D-Max (RT50) 4JK1 Injectors

Isuzu D-Max (RT50) 4JK1 Overview

The Isuzu D-Max (RT50) with the 4JK1 2.5L TD engine was produced between 2012 and 2017. This vehicle uses DENSO common rail diesel injectors (primary part number DCRI301900) operating at fuel pressures up to 2000 bar. The 4JK1 engine in the Isuzu D-Max (RT50) produces and of torque. When replacing injectors on the Isuzu D-Max (RT50) 4JK1, 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 Isuzu D-Max (RT50)

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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 Engine Codes for Isuzu D-Max (RT50)

Related Pages

DENSO 2.5L TD — browse compatible engines, vehicles, and injectors