Dakota 4WD V8-318 5.2L (1991)
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Engine speed (distributor signal)
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Idle contact switch
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Manifold Absolute Pressure (MAP) sensor
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Neutral safety switch
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Throttle Position Sensor (TPS)
The fuel injectors are controlled by the engine controller (switching the ground path), and it fires the injectors 4 times per engine revolution. The engine
controller controls the idle speed, ignition timing, and throttle stop angle. For vehicles with a manual transmission, the up-shift indicator lamp is
controlled by the engine controller based on engine load and speed.
CRUISE
This is a CLOSED LOOP mode, when the engine is at normal operating temperature. At cruising speed the engine controller receives inputs from:
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Air conditioning control positions
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Coolant temperature sensor
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Engine speed sensor (distributor pick-up)
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Manifold Absolute Pressure (MAP) sensor
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Neutral safety switch (automatic transmission)
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Oxygen sensor
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Throttle Position Sensor (TPS)
Based on these inputs the following occurs:
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The engine controller controls the ground path to the fuel injectors by applying and removing the ground from their circuit. The length
of time the ground is applied determines the injector pulse width. The engine controller also controls the sequence and times of
injection per revolution. The engine controller also controls the engine idle speed, throttle stop angle, and ignition timing.
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The engine controller monitors the oxygen sensor input and adjusts air/fuel ratio, adjusts engine idle speed, and controls ignition timing.
The engine controller adjusts the air/fuel ratio by controlling the injector pulse width, adjusts the engine idle speed by controlling the
idle speed actuation motor, and adjusts the ignition timing through the ignition control module. For vehicles with a manual transmission,
the up-shift indicator lamp is controlled by the engine controller based on engine load and speed.
ACCELERATION
This is an OPEN LOOP mode. When the engine controller receives a sudden increase in throttle position or MAP pressure, it recognizes it as a demand
for increased engine output. The engine controller responds by increasing injector pulse width to supply the necessary fuel for acceleration.
DECELERATION
This is a CLOSED LOOP mode. During deceleration the engine controller receives inputs from:
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Air conditioning control positions
^
Coolant temperature sensor
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Engine speed (distributor pick-up)
^
Idle contact switch
^
Manifold Absolute Pressure (MAP) sensor
^
Neutral safety switch
^
Oxygen sensor
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Throttle Position Sensor (TPS)
If the engine controller receives a closed throttle input from the TPS and a sudden decrease in manifold pressure from the MAP sensor, it determines that
hard deceleration is occurring. The engine controller may reduce injector firing to once per engine revolution to maintain better control of the air fuel
mixture. The engine controller also ENERGIZES the EGR solenoid and the evaporative purge solenoid to prevent EGR flow and canister purge from
occuring. The engine controller may also ENERGIZE the air switching solenoid for short periods of time in response to a high vacuum signal sent to the
engine controller by the MAP sensor.
WIDE OPEN THROTTLE
This is an OPEN LOOP mode. During wide open throttle operation the engine controller receives the following inputs:
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Coolant temperature sensor
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Manifold Absolute Pressure (MAP) sensor
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Engine speed (distributor pick-up)
^
Throttle Position Sensor (TPS)
During wide open throttle conditions the following occurs:
