Understanding the wiring intricacies when converting from an OBD2 to an OBD1 alternator can be crucial for a successful engine swap or modification. This guide focuses on Rywire engine harnesses, specifically designed for this conversion, providing a comprehensive overview of their features and compatibility. Rywire harnesses are known for their quality and ease of installation, simplifying the often-complex process of integrating an older engine into a newer vehicle.
Rywire Engine Harness: Quality and Compatibility
Rywire offers budget-friendly engine harnesses for D-series, B-series, F-series, and H-series engines, comparable to their military-spec line, differing primarily in single black wire color and expandable loom. Every harness utilizes new connectors and materials, with each connection crimped using pneumatic heads for OEM-level reliability and tagged for easy identification. Critically, heavy interference circuits are shielded and grounded to prevent voltage fluctuations. Each harness undergoes rigorous quality testing, ensuring pin-to-pin functionality and consistent resistance.
A key feature of Rywire harnesses is their OBD1 (92-95) computer connectors. While they do not support USDM OBD2 computers directly, they are compatible with aftermarket and non-USDM OBD2 computers using OBD2 plugs (except for stock H22 and GSR computers). Adapters are necessary for OBD2a or OBD2b computers.
Harness Adapters and Chassis Compatibility
Rywire harnesses incorporate a custom sub-harness designed for specific chassis, selectable from a dropdown menu during purchase. This modular design allows for chassis changes without replacing the entire wiring loom; only a new sub-harness is required. The engine harness itself can be used across multiple chassis, as long as the engine components remain the same, thanks to the separable back-side (interior/shock tower connection). Rywire provides separate back-side harnesses for existing customers, available via phone order. This significantly reduces cost and simplifies future modifications.
Connector List and Key Features for OBD2 to OBD1 Conversion
The Rywire harness includes a comprehensive array of connectors to ensure compatibility with various engine components:
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OBD2 Alternator Plug: Enables direct connection to an OBD2 alternator. This is a critical component for the conversion process, simplifying the wiring and ensuring proper alternator function.
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OBD2 Injectors (1-4): Supports OBD2 injectors, maintaining compatibility with modern fuel injection systems.
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OBD2 10-pin Distributor Plug: Allows the use of an OBD2 distributor.
In addition to these key connectors for OBD conversion, the harness includes provisions for:
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Oil Pressure Sending Unit
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Knock Sensor
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Intake Air Temperature Sensor
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Oxygen Sensor (Primary 4 Wire)
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MAP Sensor
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TPS (Throttle Position)
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Idle Control Motor
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Electronic Speed Sensor
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Ground
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Fan Switch
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H20 Sending Unit
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Reverse Lights
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Engine Coolant Temp Sensor
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Starter Signal
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VTEC Solenoid
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OBD1 Computer Plugs (A, B, D)
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Power Distribution Cap
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Two Extra Wires for customization.
Rywire Chassis Adapter Installation Instructions
Rywire provides detailed installation instructions for various chassis and OBD versions:
These guides, available as downloadable PDFs, cover installation for different Honda models, including:
- 88-91 CRX/Civic
- 90-91 Integra DA
- 92-95 Civic/Integra
- OBD2a vehicles
- OBD2b vehicles
These resources are invaluable for a successful installation, ensuring proper connection and minimizing potential issues.
Conclusion: Simplifying OBD2 to OBD1 Conversion
Rywire engine harnesses provide a robust and reliable solution for converting from OBD2 to OBD1 alternators and engine management systems. Their high-quality construction, comprehensive connector list, and chassis-specific adapters simplify the process, making them a valuable asset for engine swaps and modifications. The availability of detailed installation instructions further enhances the user experience, ensuring a smooth and successful conversion.
