When upgrading fuel injectors in your Acura Integra, understanding the difference between OBD1 and OBD2 systems, and more importantly, injector resistance, is crucial. Choosing the wrong injectors can lead to damage. This article clarifies the distinctions between OBD connector types and injector types to help you make the right choice for your Integra.
Decoding the Difference: OBD Connectors
OBD (On-Board Diagnostics) connectors provide access to the vehicle’s diagnostic system. While OBD1 and OBD2 connectors differ physically, this difference does not directly impact injector compatibility. OBD1 connectors are generally found on Integras manufactured before 1996, while OBD2 connectors are on 1996 and later models. The connector type itself doesn’t determine whether an injector will work or not. The critical factor is the injector’s internal resistance.
Injector Resistance: The Key to Compatibility
There are two primary types of fuel injectors:
- High Resistance (Saturated): These injectors operate with a continuous flow of current and are typically found in factory Integra setups. They are designed for a higher impedance, usually around 12 ohms.
- Low Resistance (Peak and Hold): These injectors utilize a pulsed current, requiring a lower impedance, around 2-3 ohms. They often provide higher flow rates for performance applications.
Using a low resistance injector in a system designed for high resistance injectors will overload the circuit and likely damage the injectors and possibly the ECU. This is why a resistor box is necessary when upgrading to low resistance injectors in an Integra originally equipped with high resistance injectors. The resistor box increases the overall resistance to a level compatible with the car’s electrical system.
Common Misconceptions: OBD and Injectors
A common misunderstanding is that OBD1 injectors are always low resistance and OBD2 injectors are always high resistance. This is incorrect. Both OBD1 and OBD2 systems can utilize either high or low resistance injectors. For example:
- OBD1 Prelude Injectors (345 cc/min): These are low resistance, peak and hold injectors.
- OBD2 Prelude Injectors (290 cc/min): These are high resistance, saturated injectors.
While they have different connectors due to the change in OBD standards, the critical difference lies in their internal resistance, not the connector type. You could use an OBD2 injector in an OBD1 car (with the appropriate adapter harness) as long as the resistance matches the original setup.
Choosing the Right Injectors for Your Integra
To avoid damaging your Integra, follow these guidelines when choosing injectors:
- Match Resistance: Determine if your Integra uses high or low resistance injectors. If unsure, consult your vehicle’s service manual or a qualified mechanic.
- Resistor Box for Low Resistance Injectors: If upgrading to low resistance injectors, always use a resistor box to protect your electrical system.
- Consider Flow Rate: Choose injectors with a flow rate appropriate for your engine modifications and tuning.
By understanding the difference between OBD connector types and, more importantly, injector resistance, you can confidently upgrade your Integra’s fuel system without risking damage. Always prioritize matching the injector resistance to your car’s requirements, regardless of the OBD generation.
