Chrysler RAM TRUCK 2500 1994 Service Manual page 982

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FUEL SYSTEM 14 - 41
Fig. 18 Sensor Location—3.9L ¥-6 or 5.2/5.9L ¥-8
Engines—Typical
mi c A I D INTAKE M A N I F O L D
Fig. 19 Sensor Location—8.0L ¥-10 Engine—Typical
train control module (PCM) relating the oxygen con­
tent of the exhaust gas. The PCM uses this
information to fine tune the air-fuel ratio by adjust­
ing injector pulse width.
The 02S sensor produces voltages from 0 to 1 volt.
This voltage will depend upon the oxygen content of
the exhaust gas i n the exhaust manifold. When a
large amount of oxygen is present (caused by a lean
air-fuel mixture), the sensor produces a low voltage.
When there is a lesser amount present (rich air-fuel
mixture) i t produces a higher voltage. By monitoring
the oxygen content and converting i t to electrical
voltage, the sensor acts as a rich-lean switch.
The oxygen sensor is equipped with a heating ele­
ment that keeps the sensor at proper operating tem­
perature during all operating modes. Maintaining
correct sensor temperature at all times allows the
system to enter into Closed Loop operation sooner.
In Closed Loop operation, the powertrain control
module (PCM) monitors the 02S sensor input (along
with other inputs). I t then adjusts the injector pulse
width accordingly. During Open Loop operation, the
PCM ignores the 02S sensor input and adjusts injec­
tor pulse width to a preprogrammed value (based on
other sensor inputs).
Refer to Open Loop/Closed Loop Modes of Opera­
tion i n this group for additional information.
EXHAUST
PIPE J9214^
Fig. 20 Oxygen Sensor Location—3.9U5.2U5.9L
LDC Engine
8.0L V-10 AND 5.9L V-8 HDC ENGINES
Dual, heated 02S sensors are used on both the
8.0L V-10 and 5.9L V-8 heavy duty cycle (HDC) en­
gines (Fig. 21). Each sensor will monitor the oxygen
content i n each exhaust downpipe.
On the 5.9L HDC V-8 engine, the left 02S sensor
monitors the odd numbered cylinders (1-3-5-7) and
fuel is controlled on the left side (bank) of the engine.
The right sensor monitors the even numbered cylin­
ders (2-4-6-8) and fuel is controlled on the right side
(bank) of the engine.
On the 8.0L V-10 engine, pairs of fuel injectors are
fired (one on each side of the engine). Because of
this, both 02S sensor readings are averaged by the
powertrain control module (PCM). This will deter­
mine a common fuel injection rate for all ten cylin­
ders.
For additional sensor operational information, refer
to the paragraphs i n the previous 3.9L/5.2/5.9L LDC
oxygen sensor section.
CRANKSHAFT POSITION S E N S O R — P C M P I N
# 2 4 — P C M INPUT
Refer to Group 8D, Ignition System for informa­
tion.