Zexel Injectors

Zexel originated as Diesel Kiki Corporation, a Japanese automotive components manufacturer founded in 1939 under a Bosch licence to produce high-pressure diesel injection pumps. The company was renamed Zexel in 1990, and subsequently acquired by Bosch and reorganised as Bosch Automotive Systems Corporation in 2000. The Zexel name now operates as a Bosch brand.

Throughout that history, Zexel developed a strong reputation as a genuine brand for precision diesel fuel injection components supplied to Nissan, Isuzu, Mitsubishi, and other manufacturers across commercial vehicles, 4WDs, trucks, and buses. The injectors Bailey's stocks carry that engineering lineage.

The Zexel products Bailey's stocks cover several key applications: the Nissan Patrol TD42 and TD42 Turbo across GQ and GU models produced between 1988 and 2003, the Nissan Patrol RD28ETI 2.8L, the Nissan Navara and Patrol ZD30 3.0L, the Holden Rodeo and Isuzu 4JH1-TC, and the Mitsubishi Pajero 4M41. Beyond passenger and 4WD applications, Zexel injectors are widely used in commercial trucks and buses from Nissan and Isuzu across industrial and commercial sectors. Compatibility depends on the specific engine code and variant, and matching the Zexel part number to your engine's exact specification is essential before ordering.

ZD30 injectors in the Nissan Patrol and Navara carry identifying letters stamped on the injector body, most commonly V or Z. These letters indicate the specific variant and should be cross-referenced against the Zexel part number to confirm correct fitment. Installing an incorrect ZD30 variant will result in fuelling and performance issues, so checking the stamped letter on the original injector before purchasing is the most reliable method of identification. If you're unsure, contact the Bailey's team with your VIN or engine details and we'll verify compatibility before anything is ordered.

The standard TD42 and TD42T use conventional Zexel mechanical injectors, and the Zexel 0050B unit is compatible with both the QD32 and TD42 engines. However, this unit is not suitable for the factory TD42Ti, which incorporates a needle lift sensor on the No.1 injector that isn't present on the standard unit. The RD28ETI also uses a Zexel injector that includes a needle lift sensor as part of the complete assembly, and this must be specified correctly when ordering. Getting the right variant for your Patrol is particularly important on the Ti and ETI models, as an incorrect injector will cause timing faults and engine management problems.

Yes. The Zexel injectors Bailey's stocks for the TD42, ZD30, 4JH1-TC, and Pajero 4M41 applications are sold as complete injector assemblies and are not designed to be field-serviced.

They are precision-built components manufactured with micron-tolerance nozzle orifices for optimal fuel atomisation, and the tight internal tolerances mean that disassembly outside of a controlled workshop environment risks damage to the precision components.

When fitting a new set, always replace the washers and seals with genuine parts rather than reusing old components. Where an injector has deteriorated, replacement with a new genuine unit is the correct approach.

On mechanical injection engines like the TD42 and 4JH1-TC, failing injectors typically show up as black or blue smoke at idle or under load, loss of pulling power particularly when towing or climbing, a rough or uneven idle, increased fuel consumption, and difficulty starting in cold conditions. Zexel injectors are manufactured to resist wear, carbon buildup, and thermal stress, but over time the nozzle tip wears and the spray pattern deteriorates.

When the spray pattern breaks down, incomplete combustion follows, which is what produces the smoke and power loss. Deteriorated washers or seals around the injector body can also allow air into the fuel system, contributing to startup smoke and fuelling inconsistency. On turbocharged applications like the TD42T and RD28ETI, worn injectors also drive exhaust gas temperatures higher by causing inconsistent fuelling across cylinders.

Genuine Zexel injectors are genuine parts, original equipment components built to the same specifications as those fitted at the factory. The spray pattern, flow rate, and nozzle geometry match what the engine was designed around.

As a genuine brand, Zexel produces components where the precision micron-tolerance orifices are difficult to replicate at the price points where aftermarket alternatives are typically sold.

The added durability from the hardened steel alloys and nickel alloys used in Zexel units is a further consideration that cheaper alternatives consistently fall short on. Units that don't match the factory spray geometry lead to incomplete combustion, carbon buildup on the pre-combustion chamber, and reduced engine life over time.

For Patrol, Pajero, and Rodeo applications, a genuine Zexel injector offers proven reliability and a longer service life than what most cheaper alternatives can deliver.

For mechanical injection engines where injectors wear at a broadly similar rate, replacing the full set when one has deteriorated is the better approach in most cases.

By the time one Zexel injector has reached the point of causing noticeable symptoms, the remaining units are typically operating at a similar wear level. Replacing a single injector on an otherwise worn set restores combustion in that one cylinder but leaves the rest contributing to imbalance, rough running, and continued smoke.

Doing the full set in one job eliminates the imbalance and avoids returning to the same labour within a short period. When replacing the full set, renew all washers and seals at the same time rather than reusing those from the original injectors.

Yes. Zexel is a genuine brand with OEM roots stretching back to the Diesel Kiki Corporation in 1939, and is now part of the Bosch Group. The brand has supplied precision diesel injection components to Nissan, Isuzu, and Mitsubishi as an original equipment manufacturer, which means the products Bailey's stocks are the same engineering that went into these vehicles at the factory, not pattern copies or rebranded alternatives.

Zexel injectors were developed for diesel fuel systems in Japanese commercial vehicles and have since been used across a wide range of diesel-powered applications. The Bailey's range focuses on 4WD, passenger, and light commercial diesel fuel applications, including the Nissan Patrol, Navara, Holden Rodeo, Isuzu, and Mitsubishi Pajero. If you're ready to order, add the relevant injector to your cart and buy with confidence knowing the part has been sourced and verified by the Bailey's team. If you'd prefer an exchange arrangement for your old core, contact the Bailey's team before completing your purchase and we'll walk you through the process. All injectors are clearly listed with price on the product page.