Dodge ram truck 3500 1996 Service Manual page 1269

mm
FUEL SYSTEM 14 - 35
DESCRIPTION AND OPERATION (Continued)
control module (PCM) indicating intake manifold air
temperature. The input is used along with inputs
from other sensors to determine injector pulse width.
As the temperature of the air-fuel stream In the
manifold varies, the sensor resistance changes. This
results In a different input voltage to the PCM.
Fig. 14 intake Manifold Air Temperature Sensor—
8.0L Engine—Typical
MANIFOLD ABSOLUTE PRESSURE (MAP)
SENSOR—3.9L/5.2L/5.9L ENGINES—PCM INPUT
The MAP sensor reacts to absolute pressure in the
intake manifold. It provides an input voltage to the
powertrain control module (PCM). As engine load
changes, manifold pressure varies. The change in
manifold pressure causes MAP sensor voltage to
change. The change in MAP sensor voltage results in
a different input voltage to the PCM. The input volt­
age level supplies the PCM with information about
ambient barometric pressure during engine start-up
(cranking) and engine load while the engine is run­
ning. The PCM uses this input along with inputs
from other sensors to adjust air-fuel mixture.
The MAP sensor is mounted on the side of the
engine throttle body (Fig. 15). The sensor is con­
nected to the throttle body with a rubber L-shaped
fitting.
MANIFOLD ABSOLUTE PRESSURE (MAP)
SENSOR—8.0L ENGINE—PCM INPUT
The MAP sensor reacts to absolute pressure i n the
intake manifold. I t provides an input voltage to the
powertrain control module (PCM). As engine load
changes, manifold pressure varies. The change in
manifold pressure causes MAP sensor voltage to
change. The change in MAP sensor voltage results in
a different input voltage to the PCM. The input volt­
age level supplies the PCM with information about
ambient barometric pressure during engine start-up
(cranking) and engine load while the engine is run-
Fig. 15 MAP and Throttle Position Sensor
Location—3.9U5.2U5.9L Engines—Typical
ning. The PCM uses this input along with inputs
from other sensors to adjust air-fuel mixture.
The MAP sensor is mounted into the right side of
the intake manifold. (Fig. 16).
Fig. 16 MAP Sensor Location—8.OL Engine—Typical
OUTPUT SHAFT SPEED SENSOR—PCM INPUT
This sensor generates a signal to the PCM relating
to the speed of the transmission main drive shaft.
This input is used with 4-speed electronic transmis­
sions only. Also refer to Vehicle Speed Sensor—PCM
Input for additional information.