8′ Classic MegaSquirt Wiring Harness - Universal Flying Lead

The MegaSquirt 8′ Wiring Harness is designed for reliability, clean routing, and ease of installation. Built from high-temp TXL automotive-grade wire, this harness includes thoughtful improvements to reduce noise, streamline wiring, and improve functionality—making it the most refined MegaSquirt wiring solution available. Whether you're wiring a fresh standalone EFI system or upgrading an existing install, this harness helps you get it right the first time with clearly labeled wires, noise-resistant construction, and a rugged DB37 connector system. Compatibility: MegaSquirt-3 (MS3) w/ MSX Expansion MegaSquirt-3 (MS3) MegaSquirt-2 (MS2) Key Features: 8′ of color-coded TXL automotive-grade wire rated for high heat Printed wire labels every 5″ with function and pin number—no paper tags Twisted and shielded ignition input cable for superior noise suppression Injector outputs use dual smaller wires (no shared pins), reducing splice count Dedicated sensor ground wire for clean signal returns Heavy-duty metal DB37 hood for EMI/RFI shielding Pre-crimped, machine-terminated DB37 connector—no solder cups Additional Enhancements: Thumbscrews on DB37 for tool-free connector tightening Pins 3–6 now wired for CAN bus and expanded I/O support Includes wiring for IAC and ignition circuits (compatible with MS1/MS2 or MS3 Primary Harness) Includes a full wiring diagram for fast setup and reference This is the harness we recommend for most MS1, MS2, and MS3 applications that wire directly to the ECU’s DB37. For relay board installs, we recommend our MegaSquirt Wiring Bundle instead. Note: This harness is not compatible with the MegaSquirt Relay Cable. Use one or the other—not both—depending on your setup.