Bosch 66825 Direct Injection High Pressure Fuel Pump
Updated June 19, 2026
The Bosch 66825 is a gasoline direct injection (GDI) high pressure fuel pump designed for select BMW M performance models. It is responsible for compressing fuel from the low-pressure electric pump to the extremely high pressures required for direct injection—up to 200 bar (approximately 2,900 psi). This pump is a critical component of the fuel delivery system, ensuring precise fuel metering and atomization for optimal combustion, power, and efficiency.
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How It Works & Design
The Bosch 66825 is an in-line, cam-driven high-pressure pump. It uses a turbine-style pumping mechanism that delivers near-silent operation and reduced wear compared to older roller-cell designs. The pump draws fuel from the low-pressure electric pump in the tank and pressurizes it to the level required by the direct injection system—up to 200 bar. This high pressure allows for precise fuel atomization directly into the combustion chamber, improving fuel economy, power output, and emissions control.
Vehicle Compatibility
This pump is engineered for BMW M models equipped with the 3.0L turbocharged inline-6 engine. Specifically, it fits the 2015–2018 BMW M3 (F80), 2015–2020 BMW M4 (F82/F83), and 2019–2021 BMW M2 (F87) with the S55 or N55 engine variants. It is a direct replacement for the original equipment pump and carries the OEM part number 13517847204. Always verify your vehicle's year, model, and engine before installation.
Common Failure Symptoms & Diagnosis
A failing high-pressure fuel pump often presents with extended cranking times, hard starting, rough idle, hesitation under acceleration, or a loss of power. The check engine light may illuminate with diagnostic trouble codes such as P0087 (fuel rail pressure too low) or P0089 (fuel pressure regulator performance). Fuel odor or visible leaks near the pump area are also signs of failure. Diagnosis typically involves monitoring fuel rail pressure with a scan tool and comparing it to specifications during cranking and running conditions.
Installation Notes
The Bosch 66825 is mounted on the cylinder head and driven by the camshaft. Installation requires relieving fuel system pressure, disconnecting high-pressure fuel lines, and carefully removing the old pump to avoid contamination. Note that gaskets are not included with this pump, so new seals or O-rings should be sourced separately. It is also advisable to inspect the low-pressure fuel pump and fuel filter, as a failing low-pressure pump can damage the high-pressure pump. After installation, the system must be primed and checked for leaks.
