Mazda Trucks 1972-1986 Repair Guide

Fast Idle Control Device


TESTING With Air Conditioning Only

When the air conditioning compressor cycles on, the vacuum pump signals the three-way solenoid valve, which in turn applies vacuum to a vacuum diaphragm unit connected to a control lever on the injection pump. Engine speed should be held at 700 rpm or increase to no more than 750 rpm. If engine speed drops below 700 rpm with the air conditioning compressor on, there is a leak in the vacuum circuit.