Feedback Carburetor System: Description

All Honda models use a feedback carburetor system (except Civic 1300 and 1500HF). The feedback carburetor system maintains the proper air/fuel ratio during engine operation. Air control valves are used to by-pass additional air into the intake manifold to adjust a temporarily rich mixture condition. The system consists of 2 feedback systems, the "X" and "M" systems.

The "X" system consists of an air control valve B, frequency solenoid B, check valves A, B, C and E, surge tanks A and B, and the control unit. Surge tank A is used as a reservoir. Surge tank B is used to dampen vacuum pulses to the air control valve B.

The "M" system consists of a check valve A (Civic 1500 and Prelude), air control valve A, frequency solenoid valve A and the control unit.