Ignition spark timing and ignition dwell time is fully controlled by the PCM/VCM. The PCM/VCM monitors information from various engine sensors, computes the desired spark timing and dwell, and firing of the ignition coil via and IC line to the coil driver.
Home/Chevrolet/Blazer/Chevrolet Blazer S15 (1994-1998)/Repair manual/Theory & Operation/Ignition Timing Control
Contents
Wiring diagrams Section: Theory & Operation- Introduction
- Terminology
- Speed Density
- Computerized Engine Controls
- Powertrain Control Module (Pcm)/vehicle Control Module (Vcm)
- Arithmetic Logic Unit (Alu)
- Central Processing Unit (Cpu)
- Power Supply
- Memories
- Input Devices
- A/c on (A/c Request) Signal
- Battery Voltage
- Brake Switch Feedback
- Engine Coolant Temperature (ECT) Sensor
- Cranking Signal
- Digital Ratio Adapter Controller (Drac)
- EGR Pintle Position
- Fuel Pump Feedback
- Gear Switches
- Knock Sensor (Ks)
- Manifold Absolute Pressure (MAP) Sensor
- Intake Air Temperature (IAT) Sensor (Some Engines)
- Oxygen Sensor (O2S)
- Park/neutral Position (Pnp) Switch
- Pressure Switch Manifold (Psm) (4L60-E Transmission)
- Throttle Position (Tp) Sensor
- Transmission Temperature Sensor (Tts) (4L60-E Transmission)
- Vehicle Speed Sensor (Vss)
- Output Signals
- ABS Control Motors (With Vcm)
- A/c Clutch Relay
- Cruise Control Solenoids
- Service Engine Soon Light
- EGR System
- Electronic Ignition (Ei)
- Fuel Injectors
- Fuel Pump & Fuel Pump Relay
- Idle Air Control (Iac) Valve
- Self-Diagnostics
- Serial Data
- Shift Solenoids (4L60-E Transmission)
- Torque Converter Clutch
- Transmission Shift Light (Manual Transmission)
- Fuel Pump
- Fuel Pressure Regulator
- Fuel Pump Relay
- Fuel Control
- Open Loop
- Closed Loop
- Central Sequential Port Injection
- Fuel System Operating Modes
- Idle Speed
- Enhanced Ignition System
- Ignition Timing Control
- Catalytic Converter
- Exhaust Gas Recirculation (EGR)
- Evaporative Emission System
- Carbon Canister
- Canister Control Valve (Ccv) (Some Federal)
- Purge Control Solenoid
- Positive Crankcase Ventilation (PCV)
- Self-Diagnostic System
- "Hard Failures"
- "Intermittent Failures"
- Service Engine/throttle Soon Light
- Miscellaneous Pcm/vcm Controls
- A/c Clutch
- A/c Pressure Switches
- Cruise Control
- Electronic Transmission (4L60-E)
- Shift Light
- A/c Compressor
- Abbreviations
- Accessory Drive Belts
- Adjustments
- Airbag
- Anti-Lock/traction Control
- Application
- Automatic Trans
- Basic Trouble Shooting
- Brakes
- Charging System
- Check Lists
- Clutches Manual & Hydraulic
- Communication Devices
- Computer Relearn
- Cooling System (Mechanical)
- Cruise Control Systems
- Diagnostic Connector Locations
- Differentials & Drive Axles
- Door Locks & Anti-Theft Systems
- Drive Cycles
- Driveline/axles
- Driveshaft & Universal Joints
- DTC Index
- Electrical
- Electrical Component Locations
- Emission Applications
- Engine
- Engine Performance
- Gauges & Instrument Panels
- General Servicing - All Makes
- Heated Glass/defoggers
- Identification
- Ignition System
- Manual & Power Steering
- Manual HVAC System
- Manual Trans
- MAP Guidelines
- Mechanical
- Mechanical - Hydraulic
- Metric Conversions
- Mirrors
- Mode 6
- Passive Restraints
- Procedures
- Removal & Installation
- Reset Procedures
- Restraints
- Rpo Codes
- Seats
- Sensor Range Charts
- Specifications
- Starter
- Steering
- Steering Column
- Steering Column Switches
- Steering Gear
- Suspension Front
- Suspension Rear
- Testing & Diagnostics
- Theory & Operation
- Traction Control Disable
- Transfer Case
- Transmission
- Wheel Alignment
- Windows
- Wiper/washer Systems
- Wiring Diagrams - Engine Performance