Electronic Engine Control 2.3L Engine

ELECTRONIC ENGINE CONTROL (2.3L, 49 STATES AND CANADA) 23-2





23-3 ELECTRONIC ENGINE CONTROL(2.3L, 49 STATES AND CANADA)





ELECTRONIC ENGINE CONTROL (2.3L, CALIFORNIA) 23-6





1990 ELECTRONIC ENGINE CONTROL (2.3L) 23-7





1990 ELECTRONIC ENGINE CONTROL (2.3L) 23-8


23-9 ELECTRONIC ENGINE CONTROL (2.3L) 1990

Exhaust Gas Recirculation (EGR)

The EGR System cools down the combustion chambers in the engine to reduce the oxides of nitrogen emitted to the atmosphere. The EEC Module controls the EGR Vacuum Regulator Solenoid, which is normally closed. When the Solenoid is energized, vacuum flows through the solenoid valve to the EGR valve. With vacuum applied to the EGR valve, the pintle opens and exhaust gas recirculates from the exhaust system back into the intake manifold.

The EGR Valve Position Sensor indicates valve position to the EEC Module by providing a voltage signal proportional to the EGR Valve position. The EEC Module determines correct EGR position depending on engine operating conditions.


Canister Purge

The carbon canister collects fuel vapors from the fuel tank and other components to be burned later in the engine. The EEC Module controls the Canister Purge solenoid, grounds the solenoid, and releases fuel vapors to be burned in the engine.

Inputs

Various input devices determine engine operating conditions. The following inputs signal the EEC Module with specific information:

The Throttle Position Sensor is a potentiometer. The sensor output is a DC voltage that varies with throttle plate angle. By monitoring the Throttle Position Sensor output, the EEC Module calculates fuel delivery requirements based on driver demand.


The BAP Sensor signals barometric pressure conditions (changes in altitude) with ignition key on and engine off, and updates this information during wide-open throttle conditions.

The Heated Exhaust Oxygen (HEGO) Sensor signals the amount of oxygen in the exhaust system. The HEGO Sensor also contains a heating element to bring the sensor up to operating temperature at a faster rate.

The Air Charge Temperature Sensor is a thermistor in which resistance decreases as manifold air temperature increases (Negative Temperature Coeffiecient or NTC).

The EEC Module detects the voltage drop across the Air Charge Temperature Sensor and uses this information to help calculate fuel delivery.

The Knock Sensor signals engine knock so that timing can be changed accordingly.

The Mass Air Flow Sensor (California emissions only) measures the amount of air flowing into the intake manifold. The Mass Air Flow Sensor uses a thermistor to measure air temperature. The EEC Module detects the voltage drop across the thermistor as air passes around it and uses this information to calculate fuel delivery, spark timing and EGR control.


The Engine Coolant Temperature Sensor is a thermistor in which resistance decreases as engine coolant temperature decreases. The EEC Module detects the voltage drop across the Engine Coolant Temperature Sensor and uses this information to help calculate fuel delivery, spark timing and EGR control.


For further diagnostic information, refer to Engine and Emissions Diagnosis Manual (volume H).