Diagnosing a faulty common rail diesel injector can be challenging but here are some common symptoms and steps to help diagnose the issue. Athol Park Wreckers can supply second hand and new genuine injectors for your Ford Ranger, Mondeo, Transit, Transit Custom, Kuga, Escape.  All parts are guaranteed.Dieselinjector

Common Symptoms of a Faulty Common Rail Diesel Injector:

  1. Rough Idle: The engine may idle roughly or unevenly when one or more injectors are not functioning properly.
  2. Loss of Power: You may notice a significant loss of power, especially during acceleration.
  3. Increased Fuel Consumption: Faulty injectors can cause the engine to burn more fuel than usual.
  4. Smoke from Exhaust: Excessive smoke from the exhaust, particularly black or gray smoke, can indicate injector issues.
  5. Misfire: The engine might misfire, especially under load or at higher RPMs.

Steps to Diagnose:

  1. Check for Fault Codes: Use a diagnostic scanner to retrieve any fault codes related to the fuel injectors. These codes can provide clues about which injector or circuit is malfunctioning.
  2. Cylinder Contribution Test: Many diagnostic tools can perform a cylinder contribution test. This test helps identify if all cylinders are contributing equally to engine power. A significant deviation in power contribution from one cylinder could indicate a faulty injector.
  3. Visual Inspection: Inspect the injectors for any signs of physical damage or leaks. Look for fuel leaks around the injector body or in the engine compartment.
  4. Listen for Abnormal Noises: Sometimes, faulty injectors can make a clicking or tapping noise. Use a mechanic’s stethoscope or a long screwdriver placed against the injector body and listen for any abnormal sounds during engine operation.
  5. Inspect Fuel System: Check the fuel system for proper pressure and flow. Low fuel pressure can lead to injector issues.
  6. Balance Rate Test: This test, if supported by your diagnostic tool, measures the difference in fuel delivery between each injector. Significant variations could indicate a problem with one or more injectors.
  7. Injector Leakage Test: Perform a leak-down test to check if the injector is holding pressure correctly when closed. Excessive leakage indicates a faulty injector.
  8. Professional Diagnostics: If you’re unsure or unable to pinpoint the issue, consider taking the vehicle to a professional mechanic or a dealership with experience in diesel engines. They can perform more advanced diagnostics and testing using specialized equipment.


Diagnosing a faulty common rail diesel injector requires a systematic approach combining visual inspection, diagnostic tools, and possibly professional expertise. Identifying the specific injector causing issues is crucial for effective repair and maintenance of your diesel engine’s performance and efficiency. Contact us at Athol Park Wreckers if you need help diagnosing and repairing your Ford Common Rail vehicle.