Many people get confused when talking about OBD1 and OBD2 injectors, often focusing on the connector type. However, the real issue isn’t about whether an injector is OBD1 or OBD2, but whether it’s high resistance or low resistance. Getting this wrong can cause serious problems.
OBD Connectors vs. Injector Resistance: Two Separate Issues
It’s important to understand that OBD1 and OBD2 refer to the diagnostic systems and, in this context, sometimes to the type of electrical connector used on the injector. On the other hand, injector resistance describes the electrical characteristics of the injector itself.
There are two main types of injectors based on resistance:
- High Resistance (Saturated) Injectors: These are designed to work with a saturated signal from the ECU.
- Low Resistance (Peak & Hold) Injectors: These require a peak and hold signal and often need a resistor box in systems designed for high resistance injectors.
The connector type (OBD1 or OBD2 style) is about physical compatibility for plugging into the wiring harness. The resistance type is about electrical compatibility with your car’s ECU.
The Real Risk: Resistance Mismatch and Frying Your System
If you install low resistance peak & hold injectors in a system designed for high resistance saturated injectors without proper modification, you risk frying your injectors and potentially damaging your ECU. This happens because low resistance injectors draw more current than a system designed for high resistance injectors is meant to handle.
This is why using a resistor box is crucial when upgrading to low resistance injectors in a car originally equipped with high resistance injectors. The resistor box reduces the current flowing to the low resistance injectors, making them compatible with the original system.
Example: Prelude Injectors
Consider Honda Prelude injectors. OBD1 Prelude injectors (345 cc/min) are low resistance, peak & hold type. OBD2 Prelude injectors (290 cc/min) are high resistance, saturated type. They also happen to have different connectors. If you were to install OBD1 Prelude injectors on a car designed for high resistance injectors (like an Integra originally equipped with saturated injectors) without a resistor box, you would create an electrical mismatch, regardless of the connector type.
Focus on Injector Type, Not Just OBD Connector
Whether an injector has an OBD1 or OBD2 style connector is less important than its resistance type (high or low, saturated or peak & hold). You can adapt connectors, but you cannot simply ignore the resistance difference. Putting an OBD2 connector on a low resistance injector won’t magically make it safe for a high resistance system.
Conclusion: Understanding Injector Resistance is Key
When dealing with injector upgrades or replacements, always prioritize understanding the injector’s resistance type and your car’s system requirements. Don’t get misled by the OBD1 or OBD2 connector discussion – focus on whether you need high resistance or low resistance injectors for your specific application to avoid electrical damage and ensure proper engine operation.
