B250 3/4 Ton Van V8-318 5.2L VIN T FI (1992)
During wide open throttle conditions, the following occurs:
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Voltage is applied to the fuel injectors with the engine controller. This controls the injection sequence and injector pulse width by turning the
ground circuit to each individual injector on and off. The engine controller ignores the oxygen sensor input signal and provides a
predetermined amount of additional fuel. This is done by adjusting injector pulse width.
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The engine controller adjusts ignition timing by turning the ground path to the coil on and off.
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The engine controller opens the ground circuit to the A/C clutch relay to disengage the A/C compressor clutch. This will be done for
approximately 15 seconds (if the air conditioning system is operating).
Deceleration
When the engine is at operating temperature, this is an Open Loop mode. During hard deceleration, the engine controller receives the following
inputs:
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Air conditioning select signal (if equipped)
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Air conditioning request signal (if equipped)
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Battery voltage
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Coolant temperature sensor
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Crankshaft position sensor
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Charge Air Temperature sensor
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Manifold absolute pressure (MAP) sensor
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Throttle position sensor (TPS)
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Sync signal (in distributor)
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Neutral safety switch (gear indicator signal)
If the vehicle is under hard deceleration with the proper rpm and closed throttle conditions, the engine controller will ignore the oxygen sensor
input signal. The controller will enter a fuel cut-off strategy in which it will not supply battery voltage to the injectors. If a hard deceleration does
not exist, the engine controller will determine the proper injector pulse width and continue injection.
Based on the above inputs, the engine controller will adjust engine idle speed through the automatic idle speed (AIS) motor.
The engine controller adjusts ignition timing by turning the ground path to the coil on and off.
The engine controller opens the ground circuit to the A/C clutch relay to disengage the A/C compressor clutch. This is done until the vehicle is no
longer under deceleration (if the A/C system is operating).
Ignition Switch Off
When ignition switch is turned to OFF position, the controller stops operating the injectors, ignition coil, ASD relay and fuel pump relay.