Chrysler 1991 - FUEL SYSTEM; DIESEL FUEL INJECTION; SYSTEM DIAGNOSIS; ENGINE CONTROLLER

FUEL SYSTEM
CONTENTS
page page
DIESEL FUEL INJECTION ................. 1 SERVICE PROCEDURES .................. 21
GENERAL DIAGNOSIS-DIESEL ,8
IIESEL FUEL INJECTION
INDEI
page
Air Intake Heater Relays—Engine Controller
Output 4
Battery Voltage—Engine Controller Input ........ 2
Brake Switch—Engine Controller Input ......... 2
Charge Air Temperature Sensor—Engine Controller
Input 2
Crank Signal—Engine Controller Input .......... 2
Engine Controller ......................... 1
General Information . . 1
Ignition Sense—Engine Controller Input ......... 2
KSB Solenoid 5
Overdrive Override Switchitch—Engine Controller
Input 2
Overdrive Solenoid—Engine Controller Output .... 5
page
Park/Neutral Switch—Engine Controller Input 2
SCi Receive and SCI Transmit—Engine Controller
Output ................................ 5
Speed Control—Engine Controller Input ......... 3
Speed Control—Engine Controller Output . 5
System Diagnosis ......................... 1
System Operation ......................... 5
Throttle Position Sensor (TPS)—Engine Controller
Input ................................. 3
Vehicle Distance (Speed) Sensor—Engine Controller
Input . 3
Wait-To-Start Lamp—Engine Controller Output ... 5
Water-ln-Fuel Lamp—Engine Controller Output ... 5
Water-ln-Fuel Sensor—Engine Controller Input ... 3
GENERAL INFORiATION
Beginning in mid 1991 model year, a Chrysler en-
gine controller regulates the diesel fuel injection sys-
tem. This group contains information about the fuel
injection system. The 1991 Rear Wheel Drive Truck
service manual describes 1991 vehicles without an
engine controller.
SYSTEM DIAGNOSIS
The engine controller monitors many of it systems
for faults. If a fault is found, the controller stores a
message in memory. Use the DRB II to access fault
messages.
ENGINE CONTROLLER
•The Single Board Engine Controller (SBEC).regu-
lates the fuel injection system. This manual refers
to the SBEC as the engine controller. The engine
controller is a pre-programmed, microprocessor digi-
tal computer (Fig. 1). The controller operates the air
intake heater relays, overdrive solenoid, and speed
control. The engine controller also powers the water
in fuel lamp and wait to start lamp
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SBEC I!
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Fig. 1 Engine Controller
- The engine controller receives various inputs. The
engine controller activates different outputs based on
these inputs.
Engine Controller Inputs
• water-in-fuel sensor
• charge air temperature sensor
• vehicle speed sensor