Fuel Injectors A2780700687 0261500065 for 2012-2022 Mercedes Benz A2760704095 1X

Mercedes-Benz · Fuel System · Direct Injection · M278 Engine · In stock

What Is the Mercedes-Benz A2780700687 Fuel Injector?

The A2780700687 (also referenced as Bosch 0261500065 or Mercedes A2760704095) is a high-pressure direct fuel injector for the Mercedes-Benz M278 4.7L twin-turbo V8 gasoline engine, fitted to numerous models from 2012 through 2022. In a direct injection (DI) system, the injector sprays fuel directly into the combustion chamber at pressures exceeding 100 bar, rather than into the intake port. This requires a precision-machined nozzle, a fast-acting piezoelectric or solenoid valve, and seals capable of withstanding combustion chamber temperatures and pressures. This listing is for a single injector — one unit, not a set of eight.

In short: A single OEM-spec direct injection fuel injector for the Mercedes M278 V8 engine — the part you replace when one cylinder is misfiring, the spark plug shows lean or rich conditions on just one hole, or a diagnostic scan points to a specific injector fault code.

What You Must Know Before Replacing a DI Injector

1. Coding/Programming Is Required After Installation

Mercedes direct injectors carry a calibration code (sometimes called an IMA code or injector flow code) laser-etched on the injector body. This code represents the individual flow characteristics of that specific injector, measured at the factory. After installing a new injector, the engine control unit (ECU) must be programmed with this code using a compatible diagnostic tool (XENTRY/DAS, Autel, or equivalent professional-grade scanner). Skipping this step causes rough running, misfires, and increased emissions because the ECU is using fuel trim values for the old injector. This is not a DIY-with-basic-tools job — plan for a shop visit or have the proper diagnostic equipment on hand.

2. Always Replace the Teflon Seal and the Combustion Chamber Seal

The injector tip seals against the cylinder head with a Teflon (PTFE) combustion seal ring. This seal is a one-time-use crush component — reusing an old seal guarantees a combustion gas leak that will carbon-pack the injector bore, making future removal extremely difficult and potentially damaging the cylinder head. Use the correct seal installation tool (a conical seating tool) to compress the new Teflon seal onto the injector tip without damaging it. Never lubricate the Teflon seal — install it dry, as lubricant prevents proper seating and will burn off, leaving a leak path.

3. Why Replacing Just One Injector Can Be Problematic

On a high-mileage M278 engine, the remaining seven injectors have wear and deposits that affect their spray pattern and flow rate. A new injector flows differently from a 100,000-mile injector, even with calibration coding. This can cause cylinder-to-cylinder imbalance that the ECU's fuel trim struggles to compensate for. Many shops recommend replacing injectors in complete bank sets (four at a time) or all eight together on higher-mileage engines. If you are replacing just one injector due to a confirmed electrical or mechanical failure on a single cylinder, be aware that fuel trim adaptation may take several drive cycles to settle, and the engine may still exhibit slight roughness at idle for the first few hours of operation.

Key Specifications

Frequently Asked Questions

How do I confirm this injector fits my specific Mercedes model and year?

Do not rely on year/model alone — the same model year can have different engine variants. Look up your VIN in a Mercedes EPC (Electronic Parts Catalog) or use an online VIN decoder to confirm your engine is the M278 4.7L twin-turbo V8. Then verify the injector part number from the EPC matches A2780700687 or A2760704095. Cross-check with the Bosch number 0261500065. If all three match, the injector is correct for your engine. Contact us with your VIN if you need help confirming.

Do I need to replace the high-pressure fuel line when I replace the injector?

The high-pressure line between the fuel rail and the injector uses a metal-to-metal sealing interface. Mercedes specifies these lines as single-use — once the sealing surface has been torqued and then loosened, it may not seal properly when re-tightened. Many experienced technicians re-use lines if the sealing surfaces are clean and undamaged, but the official procedure calls for replacement. A leaking high-pressure fuel line at 100+ bar creates a fire hazard. The Teflon combustion seal on the injector tip must also be replaced — it is included with some injectors and sold separately with others. Verify what is included in the box before beginning the job.

What are the symptoms that tell me an injector has failed rather than an ignition coil or spark plug?

Start with a diagnostic scan for cylinder-specific misfire codes (P0300-P0308). Swap the suspect cylinder's ignition coil with an adjacent cylinder and clear the codes. If the misfire follows the coil, the coil is bad — not the injector. If the misfire stays on the original cylinder, swap the spark plug next. If the misfire still stays on the same cylinder after confirming good coil and plug, the injector is the prime suspect. A borescope inspection showing a washed-clean piston crown (from excess fuel) or an unusually dry/white spark plug (from a lean condition) on just one cylinder further points to an injector issue.

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