The vane ( flap ) type air flow meters ( Bosch L-Jetronic and early Motronic EFI systems or Hitachi ) actually measure air volume, whereas the later " hot wire " and " hot film " air mass meters measure speed of air flow.
12.
The use of a vane-type air flow meter ( AFM ), which restricted air flow slightly but produced cleaner emissions that conformed to the U . S . regulations, limited the power considerably-the Japanese model, which uses a manifold absolute pressure ( MAP ) sensor, was originally rated at.
13.
In many cars ( with the exception of some turbocharged models ), inputs from the air flow meter are also ignored, as they might otherwise lower engine performance due to the mixture being too rich or too lean, and increase the risk of engine damage due to detonation if the mixture is too lean.
14.
The fuel distributor is mounted atop a control vane through which all intake air must pass, and the system works by varying fuel volume supplied to the injectors based on the angle of the air vane in the air flow meter, which in turn is determined by the volume of air passing the vane, and by the control pressure.
