How to Test Common Rail Injectors: A Standard Diesel Injector Testing Procedure

Introduction

For any diesel repair workshop, knowing exactly how to test common rail injectors is the foundation of profitable diagnostics. A faulty injector can lead to poor engine performance,
increased emissions, or even severe engine damage. In this guide, we will walk you through the standard diesel injector testing procedure to ensure 100% accuracy in your daily repair work.

Step 1: Visual Inspection and Cleaning

Before placing the injector on your common rail injector test bench, you must perform a thorough ultrasonic cleaning. Dirt or carbon deposits can ruin the highly sensitive flow sensors of the testing equipment.

Step 2: Mounting and Sealing Check

Mount the injector securely. The first crucial step in the diesel fuel injection testing process is the leak test. Apply high pressure (up to 2000 or 2500 bar depending on the model) to check for static leaks at the nozzle,
control valve, and backflow areas.

Step 3: The Core Testing Steps

A professional diesel pump and injector tester will automatically run through several critical stages:

VL (Full Load Test): Measures the maximum fuel delivery at maximum rail pressure.

EM (Emission Test): Checks the mid-range fuel delivery.

LL (Idle Speed Test): Ensures engine stability at low RPMs.

VE (Pre-injection Test): Crucial for modern engines to reduce combustion noise.

Conclusion

Following a strict diesel injector testing procedure guarantees that your customers won't return with the same problem. To achieve this, you need highly accurate equipment.
If you are looking to upgrade your workshop, explore our latest computerized common rail test bench designed for high-precision Bosch, Denso, and Delphi testing.