Ford F-100, F-150, F-250, F-350 Pick-up Trucks, Bronco Repair Manual 1976-1986

• 3.8L V6 (232 cid)
• 4.2L V8 (255 cid)
• 4.9L inline 6-cylinder (300 cid)
• 5.0L V8 (302 cid)
• 5.8L V8 (351 cid)
• 5.9L V8 (360 cid)
• 6.5L V8 (390 cid)
• 6.6L V8 (400 cid)
• 6.9L diesel V8
• 7.5L V8 (460 cid)

Ford vehicles, employ the 4th generation Engine Control system, commonly designated EEC-IV, to manage fuel, ignition and emissions on vehicle engines.

The Engine Control Assembly (ECA) is given responsibility for the operation of the emission control devices, cooling devices, cooling fans, ignition and advance and in some cases, automatic transmission functions. Because the EEC-IV oversees both the ignition timing and the fuel injector operation, a precise air/fuel ratio will be maintained under all operating conditions. The ECA is a microprocessor or small computer which receives electrical inputs from several sensors, switches and relays on and around the engine.

Based on combinations of these inputs, the ECA controls outputs to various devices concerned with engine operation and emissions. The engine control assembly relies on the signals to form a correct picture of current vehicle operation. If any of the input signals is incorrect, the ECA reacts to what ever picture is painted for it. For example, if the coolant temperature sensor is inaccurate and reads too low, the ECA may see a picture of the engine never warming up. Consequently, the engine settings will be maintained as if the engine were cold. Because so many inputs can affect one output, correct diagnostic procedures are essential on these systems.

One part of the ECA is devoted to monitoring both input and output functions within the system. This ability forms the core of the self-diagnostic system. If a problem is detected within a circuit, the controller will recognize the fault, assign it an identification code, and store the code in a memory section. Depending on the year and model, the fault code(s) may be represented by two or three digit numbers. The stored code(s) may be retrieved during diagnosis.

While the EEC-IV system is capable of recognizing many internal faults, certain faults will not be recognized. Because the computer system sees only electrical signals, it cannot sense or react to mechanical or vacuum faults affecting engine operation. Some of these faults may affect another component which will set a code. For example, the ECA monitors the output signal to the fuel injectors, but cannot detect a partially clogged injector. As long as the output driver responds correctly, the computer will read the system as functioning correctly. However, the improper flow of fuel may result in a lean mixture. This would, in turn, be detected by the oxygen sensor and noticed as a constantly lean signal by the ECA. Once the signal falls outside the pre-programmed limits, the engine control assembly would notice the fault and set an identification code.

• Tune-up and routine maintenance
• Engine and overhaul procedures
• Cooling, heating and air-conditioning systems
• Fuel and exhaust systems
• Engine electrical systems
• Emissions control systems
• Transmission
• Brakes
• Suspension and steering systems
• Body
• Chassis electrical system
• Wiring diagrams