Operation CHARM: Car repair manuals for everyone.

California Models

Component Locations:





CIS-E SYSTEM

The CIS-E Computerized Engine Control system consists of the basic CIS (Continuous Injection) fuel injection system and electronic controls which are added for air/fuel mixture correction, idle stabilization and exhaust emission control. The electronic control unit (ECU) receives input signals from the airflow sensor position indicator (potentiometer), coolant temperature sensor, transistorized ignition system (EZL), throttle valve switch, micro switch, altitude sensor, vehicle speed sensor, engine systems (MAS) control unit, intake air temperature sensor, transmission range indicator, and oxygen sensor. The ECU processes these input signals and calculates the appropriate correction values which are sent to the electro-hydraulic actuator (air/fuel mixture control), electric purge valve, EGR switchover valve and the idle speed control valve.
California models are equipped with "On Board Diagnostic" trouble shooting capabilities. If a fault occurs in the CIS-E fuel injection system the "CHECK ENGINE" light will illuminate alerting the driver of an emission related malfunction and the control unit will record the fault. Hard failures and intermittent failures will cause the light to remain on until the malfunction is repaired. If a CIS-E system sensor fails, the control unit will use a substitute value in its calculations to continue engine operation (limp home mode). An On Board Diagnostic Connector consisting of a light emitting diode (LED) and push button or an impulse counter is used to extract trouble codes. Federal and California control units are not interchangeable.

EZL System Diagram, (Typical):





EZL IGNITION SYSTEM

Dwell and ignition angle are determined by the (EZL) transistorized ignition system. The EZL electronic control unit (ECU) receives input signals from the ignition switch, crankshaft position sensor, intake manifold vacuum signal, coolant temperature sensor, throttle valve switch, and the CIS-E control unit. Like the CIS-E control unit, the EZL control unit processes these signals, calculates the appropriate dwell/ignition angle, and simultaneously switches the ignition coil ground circuit.

Engine Systems (MAS) Control Unit:





ENGINE SYSTEMS (MAS)

The engine systems (MAS) control unit replaces the previous fuel pump relay. The MAS unit controls the function of the fuel pumps, A/C compressor activation, O2 sensor heater, air injection pump, A/T kickdown, and maximum vehicle speed inhibitor. The MAS control unit also has malfunction memory capabilities which may be accessed with an impulse counter at the on-board [1][2]diagnostic connector.