Federal Models

Fig. 4 CIS-E System Components:

The CIS - E Computerized Engine Control system consists of the basic CIS (Continuous Injection System) fuel injection system and electronic controls which are added for air/fuel mixture correction. 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, A/C compressor, transmission range indicator, and oxygen sensor. The ECU processes these input signals and calculates the appropriate correction value which is sent to the electro-hydraulic actuator, air injection relay, and the purge valve relay. Furthermore, federal models are equipped with "On Board Diagnostic" trouble shooting capabilities. If a fault occurs in the oxygen sensor circuit the "CHECK ENGINE" light will illuminate alerting the driver of an emission related malfunction. Hard failures will cause the light to remain on until the malfunction is repaired. However, since the control unit does not have memory capabilities intermittent failures may cause the light to flicker or go out when the intermittent fault is not present. Failure codes are transmitted via the lambda measuring circuit of the diagnostic socket and are read with the Bosch "On-Off" Ratio Tester (KDJE-P600) or equivalent. 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).
Dwell/ignition angle and idle speed are determined by separate control units. The (EZL) transistorized ignition system controls dwell/ignition angle, and the idle speed stabilization control unit regulates idle speed.

EZL System Diagram:

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.
The idle speed stabilization control unit receives input signals from the coolant temperature sensor, EZL control unit, throttle valve switch, electronic speedometer, transmission selector position, and the A/C compressor switch. The idle speed control unit processes the signals and sends an output voltage to adjust the idle control valve.