See Figures 1, 2 and 3
The main computers, which controls the fuel injection system on all vehicles covered by this information, are referred to as the Powertrain Control Module (PCM) on all non-Premier and Monaco vehicles. On 1988-90 and early 1991 Premier and Monaco vehicles, it is called the Engine Control Unit (ECU), whereas on the late 1991 and all 1992 Premier and Monaco models (with the Direct Ignition System), it is known as the Single-Board Engine Controller (SBEC). The engine computer (PCM, ECU or SBEC) is a digital computer containing a microprocessor. The engine computer receives input signals from various switches and sensors that are referred to as engine computer inputs. Based on these inputs, the engine computer adjusts various engine and vehicle operations through devices referred to as engine computer outputs.
The engine computer inputs are as follows:
The engine computer outputs:
Based on inputs it receives, the engine computer adjusts fuel injector pulse width, idle speed, ignition spark advance, ignition coil dwell and canister purge operation. The engine computer regulates the cooling fan, air conditioning and speed control systems. The engine computer changes the alternator charge rate by adjusting the generator field.
The distributor pick-up signal is sent to the engine computer. If the engine computer does not receive a distributor signal within approximately one second of engine cranking, the ASD relay and fuel pump relay are deactivated. When these relays are deactivated, power is shut off to the fuel injector, ignition coil, oxygen sensor heating element and fuel pump.
The engine computer contains a voltage converter that changes battery voltage to a regulated 8.0 volts. The 8.0 volts power the distributor pick-up and vehicle speed sensor. The engine computer also provides a 5.0 volt supply for the coolant temperature sensor, manifold absolute pressure sensor and throttle position sensor.
REMOVAL & INSTALLATION
See Figures 4 through 10
- Remove the air cleaner duct or air cleaner assembly from the engine.
- Remove the battery from the vehicle as described in Engine Electrical .
- Remove the engine computer mounting screws.
- Remove the 60-way connector from the engine computer. Remove the engine computer from the vehicle.
- Plug the 60-way connector into the engine computer.
- Install the PCM on the inside left front fender. Install and tighten the mounting screws.
- Install the battery into the vehicle.
- Install the air cleaner duct or air cleaner assembly.