Service function guideFuel Injector Testing

This guide covers the complete process of fuel injector testing, from understanding the system's operation to performing resistance, balance, and spray pattern checks on both port and direct injection engines. It is written for working mechanics and experienced DIYers who already have a solid grasp of engine management fundamentals and want a structured, repeatable diagnostic routine. By the end, you will be able to isolate a faulty injector, interpret the test results against factory specifications, and decide whether cleaning, replacement, or further circuit diagnosis is the correct next step. The procedures emphasize safe fuel handling and the use of service information for exact values, since specifications vary widely across makes and models.