Injection rail

In high-pressure injection rails there are pressure sensors, as well as pressure regulating valves in the diesels. These sensors and valves are prone to wear and failure, and are expensive new. The rails themselves are also prone to clogging and corrosion—though this is less common.

When the sensors and valves go, especially in the late-model diesels—it is often cheaper to replace the entire rail with a second-hand unit than buy the sensors or valves brand new from BMW.

Most late-model BMWs (almost all since 2007) use direct injection fuel systems—which require high-pressure (2,000-3,000 psi) to deliver fuel to the combustion chambers. These systems require high-pressure injection rails to regulate pressure and ensuring even distribution of fuel to each injector.

The best way to determine fitment compatibility of an injection rail is to match the BMW part numbers from the catalogue. This can be done by decoding your vehicle’s VIN in a BMW EPC (electronic part catalogue.)

If you don’t have access to an EPC, provide our team with your vehicle’s 17-digit VIN—and we’ll check our stock for a compatible match.

Injection rails are generally unique to an engine type—with little interchangeability between them.

There is of course some interchangeability between models with the same engine type, but the engines in larger SAV/SAC models will typically have more heavy-duty fuel systems than their passenger vehicle counterparts.