When dealing with fuel injectors, especially for OBD2 systems, it’s crucial to understand that the connector type is not the primary concern when it comes to potential damage. The real issue lies in the resistance of the injector, specifically whether it’s high resistance (saturated) or low resistance (peak & hold). Confusing these two can lead to serious problems, including frying your fuel injection system.
There are two main types of fuel injectors categorized by their resistance:
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High Resistance (Saturated) Injectors: These injectors are designed to be directly driven by the ECU (Engine Control Unit) without needing any external resistors. They operate at a higher resistance, which limits the current flow.
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Low Resistance (Peak & Hold) Injectors: These injectors require a higher current to open quickly. To manage this, systems using peak & hold injectors often employ a resistor box to limit the current after the initial “peak” opening phase, moving to a “hold” current to keep the injector open.
The danger arises when you install low resistance peak & hold injectors into a system designed for high resistance saturated injectors. Why? Because the system is not designed to limit the higher current draw of the low resistance injectors. This excessive current can overheat and damage the injector driver circuits in your ECU, effectively “frying” them. This damage is not related to whether the injector has an OBD1 or OBD2 connector; it’s solely about the injector’s resistance and the system’s compatibility.
For instance, consider upgrading your Acura Integra (Teg) which is originally designed for saturated injectors. If you were to install higher flowing Prelude injectors from an OBD1 model (which are low resistance peak & hold), you would risk damaging your Integra’s ECU unless you also installed a resistor box. The OBD1 connector on the Prelude injector is irrelevant to this risk; the problem is the low resistance type. Similarly, using 450 cc/min low resistance Mitsubishi injectors also necessitates a resistor box to prevent system damage.
It’s important to differentiate between two separate aspects:
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OBD Connector Type (OBD1 vs. OBD2): This refers to the physical connector used to plug the injector into the wiring harness. While different, this is not the primary factor affecting system damage.
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Injector Resistance Type (Peak & Hold vs. Saturated): This is the critical factor. Mismatching injector resistance with the system design is what leads to potential electrical damage.
Therefore, even if you find an OBD2 injector that is of the peak & hold (low resistance) type, installing it in a system designed for saturated injectors without a resistor box will still lead to the same risk of frying your system.
Choosing saturated type injectors for upgrades can simplify things as you generally avoid the complexities of resistor boxes. However, saturated injectors might not always be available in the exact flow rate you require for performance upgrades.
A good example to remember is with Prelude injectors:
- OBD1 Prelude injectors (345 cc/min) are peak & hold (low resistance).
- OBD2 Prelude injectors (290 cc/min) are saturated (high resistance).
They also utilize different connector types, further emphasizing that connector type and resistance type are distinct characteristics to consider when working with fuel injectors. Always verify the resistance type and system compatibility when upgrading or replacing your Obd2 Injectors to prevent electrical damage.
