Used BMW 8 Series Air Flow Meter

Yes, but only on petrol-engined variants — the air flow meter (also called a mass air flow sensor or MAF sensor) measures the air entering the engine and is a standard fitment on the petrol engines used in the 8 Series. The original E31 8 Series (1990–1999) used large-capacity naturally aspirated petrol V8 and V12 engines, all of which used a MAF sensor. The modern G15 8 Series (2018–present, including the G14 Convertible and G16 Gran Coupé) uses turbocharged petrol and, in some markets, diesel engines, and these also use a MAF sensor — so the part does genuinely exist across the range.

The E31 8 Series ran from 1990 to 1999 with no formal facelift, so both cars sit within the same generation — however, fitment of the MAF sensor is determined primarily by the engine code, not the model year alone. Both 840Ci models used the M62 V8, but there were running production changes across the build run, so confirm the exact engine code from your V5 or a VIN check and quote it to the breaker to make sure the sensor matches your specific build.

Trim and badge level do not affect the air flow meter — what matters is the engine code, because the MAF sensor is calibrated to the specific engine. The 850CSi used the S70 V12 engine while the 840Ci used the M62 V8, so these are different engines requiring different sensors, but that difference comes from the engine code, not the trim designation itself. Always match by engine code rather than by the badge on the boot lid.

The G15 8 Series received a facelift in 2022, which brought visual and some specification updates, but the core engine families — including the B58 six-cylinder and S58/N63 V8 units — continued across both pre-facelift and post-facelift cars. Engine code is the key compatibility factor, so if both cars share the same engine code the MAF sensor is likely to correspond, but confirm this with the breaker against your registration before buying, as ancillary and mounting details can change mid-production without a formal facelift.

No — petrol and diesel engines use fundamentally different MAF sensors calibrated to their respective air and fuelling systems, so a sensor from a diesel variant will not be compatible with your petrol 840i. Always specify both your fuel type and your engine code when asking a breaker for a quote, as this rules out mismatches straight away.

The air flow meter on most BMW applications is a straightforward sensor that does not typically require the same level of ECU coding as some other BMW components — however, whether a used unit needs any adaptation or coding to your specific vehicle is something you should confirm with the breaker or your BMW specialist against your registration, as this can vary by engine and model year. It is always worth clearing any fault codes and verifying live sensor data with a diagnostic tool after fitting a used MAF sensor.