Manifold Absolute Pressure (Map) Sensor; Fuel Injectors - Kohler Command PRO ECH630 Service Manual

Section 5
EFI Fuel System
Manifold Absolute Pressure Sensor
Figure 5-11. Manifold Absolute Pressure Sensor
and Connector.
General
The manifold absolute pressure (MAP) sensor
provides immediate manifold pressure information
to the ECU. The MAP measures the diff erence in
pressure between the outside atmosphere and the
vacuum level inside the intake manifold and monitors
pressure in the manifold as the primary means of
detecting load. The data is used to calculate air
density and determine the engine's mass air fl ow rate,
which in turn determines the required ideal fueling.
The MAP also stores instant barometric pressure
reading when the key is turned ON.
Service
The manifold absolute pressure sensor is a sealed,
non-serviceable assembly. A faulty sensor must be
replaced. If a blink code indicates a problem with the
manifold absolute pressure sensor, it can be tested as
follows:
1. Make sure all connections are making proper
contact and are free of dirt and debris. Remove
the blower housing. Slide the locking tab out and
pull off the manifold absolute pressure connector.
Turn the key switch to ON and check with a volt
meter by contacting the red lead to pin 1 and the
black lead to pin 2. See Figure 5-11 for pin
location. There should be 5 volts present,
indicating the ECU and wiring harness are
functioning.
2. Check continuity in wire harness. Ohms between
Pin 3 at the sensor connector and Black pin 11
connector at ECU should be near zero ohms. If no
continuity is measured or very high resistance,
replace wire harness.
5.16
Locking
Tab

Fuel Injectors

Pin 1 Pin 3
Pin 2
Figure 5-12. Fuel Injector.
General
The fuel injectors mount into the intake manifold,
and the high pressure fuel line att aches to them at
the top end. Replaceable O-rings on both ends of the
injector prevent external fuel leakage and also insulate
it from heat and vibration. A special clip connects
each injector to the high pressure fuel line and holds
it in place. The O-rings and retaining clip should be
replaced any time the fuel injector is separated from
its normal mounting position. DO NOT reuse existing
O-rings or retaining clips as fuel leakage may result.
When the key switch is on, the fuel pump module will
pressurize the high pressure fuel line to 39 psi, and
voltage is present at the injector. At the proper instant,
the ECU completes the ground circuit, energizing the
injector. The valve needle in the injector is opened
electromagnetically, and the pressure in the high
pressure fuel line forces fuel down through the inside.
The director plate at the tip of the injector contains a
series of calibrated openings which directs the fuel
into the manifold in a cone-shaped spray patt ern.
3. Check to make sure the intake manifold is not
loose and the MAP sensor is not loose. Loose
parts would allow a vacuum leak, making the
MAP sensor report misleading information to the
ECU.
a. Tighten all hardware and perform an ECU
Reset and a TPS Learn Procedure to see if the
MIL will display a fault with the MAP sensor
again. If the MIL fi nds a fault with the MAP
sensor, replace it.