5
B
MULTI-PORT FUEL INJECTION DESCRIPTIONS AND SYSTEM OPERATION
SERVICE MANUAL NUMBER 23
90-861326--1   MARCH 1999 Page 5B-1
FUEL SYSTEM
Section 5B - Multi-Port Fuel Injection Descriptions And
System Operation
Table of Contents
Identification 5B-2. . . . . . . . . . . . . . . . . . . . . . . . 
Electronic Control Module (ECM) 5B-2. . . 
General Information 5B-3. . . . . . . . . . . . . . . . . 
Introduction 5B-3. . . . . . . . . . . . . . . . . . . . . . 
Visual / Physical Inspection 5B-3. . . . . . . . 
Basic Knowledge and Tools Required 5B-3
Electrostatic Discharge Damage 5B-4. . . . 
Diagnostic Information 5B-4. . . . . . . . . . . . 
Wiring Harness Service 5B-4. . . . . . . . . . . 
Wiring Connector Service 5B-5. . . . . . . . . . 
Abbreviations 5B-6. . . . . . . . . . . . . . . . . . . . . . . 
ECM Self-Diagnostics 5B-7. . . . . . . . . . . . . . . . 
Diagnostic Code Tool With Malfunction 
  Indicator Lamp 5B-7. . . . . . . . . . . . . . . . . . 
Intermittent Malfunction Indicator 
  Lamp 5B-8. . . . . . . . . . . . . . . . . . . . . . . . . . 
Reading Codes 5B-8. . . . . . . . . . . . . . . . . . . 
Scan Tools 5B-9. . . . . . . . . . . . . . . . . . . . . . . 
EFI Diagnostic Circuit Check 5B-9. . . . . . . 
Scan Tool Use With Intermittents 5B-10. . . 
Non-Scan Diagnosis of Driveability 
  Concerns (With No Codes Set) 5B-11. . . . 
Special Tools 5B-12. . . . . . . . . . . . . . . . . . . . . . . 
Precautions 5B-13. . . . . . . . . . . . . . . . . . . . . . . . 
Electronic Control Module (ECM) and 
  Sensors 5B-15. . . . . . . . . . . . . . . . . . . . . . . . . . . 
General Description 5B-15. . . . . . . . . . . . . . . 
Computers and Voltage Signals 5B-15. . . . 
Analog Signals 5B-15. . . . . . . . . . . . . . . . . . . 
Digital Signals 5B-16. . . . . . . . . . . . . . . . . . . . 
Engine Control Module (ECM) 5B-18. . . . . . 
Speed Density System 5B-19. . . . . . . . . . . . 
ECM Input and Sensor Descriptions 5B-20. 
Engine Control Module (ECM) and 
  Delco EST Distributor System 5B-25. . . . . 
Spark Management 5B-27. . . . . . . . . . . . . . . . . . 
High Energy Ignition with Ignition 
  Control (IC) 5B-27. . . . . . . . . . . . . . . . . . . . . 
Modes Of Operation 5B-27. . . . . . . . . . . . . . 
Distributor Module Mode 5B-29. . . . . . . . . . . 
ECM Control Mode 5B-29. . . . . . . . . . . . . . . 
Base Ignition Timing 5B-30. . . . . . . . . . . . . . 
Results of Incorrect Operation 5B-32. . . . . . 
Fuel Metering System 5B-33. . . . . . . . . . . . . . . . 
General Description 5B-33. . . . . . . . . . . . . . . 
Cool Fuel Systems 5B-33. . . . . . . . . . . . . . . . 
Modes of Operation 5B-33. . . . . . . . . . . . . . . 
454/502 Mag MPI and 8.2L MPI 
  Multi-Port Injection Components 5B-35. . . 
7.4L MPI Multi-Port Injection 
  Components 5B-39. . . . . . . . . . . . . . . . . . . . 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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