Multi-point injection (Audi 100 C4)

The 2.8-liter 6-cylinder engine is equipped with an injection system with the designation MPI. This abbreviation hides the English words Multi Point Injection - in Russian "multipoint injection". (The distinguishing feature of the MPI injection system is the air flow meter in the air intake sleeve at the rear right in the engine compartment.)

The nearly identical injection system of the 2.6-liter engine is called MPFI, in fact, only to distinguish them. This abbreviation in turn stands for Multi Point Fuel Injection. (The distinctive feature of the system is the absence of an air meter.)

The technical distinguishing feature of both systems is the way they measure quantity (or masses) incoming air:

MPI uses a hot-wire anemometer for this purpose.

MPFI uses an exhaust manifold pressure sensor for this purpose (built into the control unit and connected to the exhaust manifold by a connecting hose), as well as an incoming air temperature sensor (in the exhaust manifold).

A link to the original source is available on the website AudiManual