General Description - Fuel Metering; Acceleration Mode; Accelerator Controls; Battery Voltage Correction Mode - Isuzu 1999 RODEO Workshop Manual

6E1–432 RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION
engine. The air duct assembly routes filtered air to the
throttle body. Air enters the engine by the following steps:
1. Through the throttle body.
2. Into the intake manifold.
3. Through the cylinder head intake ports.
4. Into the cylinders.
GENERAL DESCRIPTION — FUEL
METERING

Acceleration Mode

The PCM provides extra fuel when it detects a rapid
increase in the throttle position and the air flow.

Accelerator Controls

The accelerator control system is a cable–type system
with specific linkage adjustments.
Refer to Cable Adjustment.

Battery Voltage Correction Mode

When battery voltage is low, the PCM will compensate for
the weak spark by increasing the following:
f The amount of fuel delivered.
f The idle RPM.

CMP Signal

The PCM uses the camshaft position (CMP) sensor
signal to determine the position of the number 1 piston
during its power stroke, allowing the PCM to calculate
true sequential multiport fuel injection (SFI). Loss of this
signal will set a DTC P0341 or DTC P0342. If the CMP
signal is lost while the engine is running, the fuel injection
system will shift to a calculated sequential fuel injection
based on the last fuel injection pulse, and the engine will
continue to run. The engine can be restarted and will run
in the calculated sequential mode with the fault is present,
with a 1–in–4 chance of being correct.

Clear Flood Mode

Clear a flooded engine by pushing the accelerator pedal
down all the way. The PCM then de–energizes the fuel
injectors. The PCM holds the fuel injectors de–energized
as long as the throttle remains above 80% and the engine
speed is below 800 RPM. If the throttle position becomes
less than 80%, the PCM again begins to pulse the
injectors ON and OFF, allowing fuel into the cylinders.

Deceleration Fuel Cutoff (DFCO) Mode

The PCM reduces the amount of fuel injected when it
detects a decrease in the throttle position and the air flow.
When deceleration is very fast, the PCM may cut off fuel
completely for short periods.
Engine Speed/Vehicle Speed/ Fuel Disable
Mode
The PCM monitors engine speed. It turns off the fuel
injectors when the engine speed increases above 6000
RPM. The fuel injectors are turned back on when engine
speed decreases below 5750 RPM.

Fuel Cutoff Mode

No fuel is delivered by the fuel injectors when the ignition
is OFF. This prevents engine run–on. In addition, the
PCM suspends fuel delivery if no reference pulses are
028RX002
detected (engine not running) to prevent engine flooding.

Fuel Injector

The sequential multiport fuel injection (SFI) fuel injector is
a solenoid–operated device controlled by the PCM. The
PCM energizes the solenoid, which opens a valve to allow
fuel delivery.
The fuel is injected under pressure in a conical spray
pattern at the opening of the intake valve. Excess fuel not
used by the injectors passes through the fuel pressure
regulator before being returned to the fuel tank.
A fuel injector which is stuck partly open will cause a loss
of fuel pressure after engine shut down, causing long
crank times.
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