Electronic Fuel Injection (EFI) and Engine Management System Wiring Diagram

Comprehensive wiring diagram detailing a modern EFI system with complete sensor network, fuel delivery, and ignition control. Features exact voltage specifications for sensors (0-5V, 0-1V), signal types (AC, Hall Effect, variable resistance), color-coded wiring, and Layout ratings including 12Ω injectors and 20kV ignition voltage. Organized into functional subsystems: sensor inputs, fuel management, and ignition control with complete ground circuit mapping.

graph TD
    B[Battery 12V] -->|Red 10AWG| MR[Main Relay]
    MR -->|Protected Power| ECU[Engine Control Unit]
    
    subgraph Sensor Inputs
        MAF[Mass Air Flow Sensor] -->|0-5V Gray/Red| ECU
        O2F[Front O2 Sensor] -->|0-1V White| ECU
        O2R[Rear O2 Sensor] -->|0-1V White/Black| ECU
        CTS[Coolant Temp Sensor] -->|Variable Resistance Green| ECU
        TPS[Throttle Position Sensor] -->|0-5V Yellow| ECU
        CKP[Crankshaft Position Sensor] -->|AC Signal Blue| ECU
        CMP[Camshaft Position Sensor] -->|Hall Effect Brown| ECU
        KS[Knock Sensor] -->|AC Signal Purple| ECU
        IAT[Intake Air Temp] -->|Variable Resistance Orange| ECU
        MAP[Manifold Pressure] -->|0-5V Green/Black| ECU
    end
    
    subgraph Fuel System
        ECU -->|Ground Control Brown| INJ[Fuel Injectors 12Ω]
        ECU -->|PWM Control Yellow| FP[Fuel Pump Relay]
        FP -->|12V Power Red| PUMP[Fuel Pump]
        PUMP -->|Fuel Pressure| INJ
        FPR[Fuel Pressure Regulator] -->|Pressure Control| PUMP
        MAP -->|Vacuum Reference| FPR
    end
    
    subgraph Ignition System
        ECU -->|5V Reference White| ICM[Ignition Control Module]
        ICM -->|High Voltage| IC[Ignition Coils]
        IC -->|20kV| SP[Spark Plugs]
        CKP -->|Timing Signal| ICM
    end
    
    B -.->|Ground Black| G[Ground Points]
    ECU -.->|Ground Black| G
    MAF -.->|Ground Black| G
    TPS -.->|Ground Black| G
    PUMP -.->|Ground Black| G
    
    style B fill:#ff9999,stroke:#333,stroke-width:2px
    style ECU fill:#99ff99,stroke:#333,stroke-width:2px
    style INJ fill:#9999ff,stroke:#333,stroke-width:2px
    style MAF fill:#ffff99,stroke:#333,stroke-width:2px
    style ICM fill:#ff99ff,stroke:#333,stroke-width:2px
    style G fill:#cccccc,stroke:#333,stroke-width:2px
    style FP fill:#ffcc99,stroke:#333,stroke-width:2px

About This Diagram

This wiring diagram provides a detailed view of the electronic fuel injection (efi) and engine management system wiring diagram. Use this diagram for troubleshooting electrical issues, understanding system connections, and performing maintenance on your vehicle's electrical systems.