Common Diesel Engine Problems That Require Repair

The most common diesel engine problems that require repair include:

  1. Diesel Won’t Start
  2. Hard To Start Diesel Engine
  3. Diesel Runs Rough At Lower RPMs
  4. Lack of Diesel Engine Power
  5. Diesel Engine Knocking or Pinging
  6. Black Smoke
  7. White Smoke
  8. Blue Smoke

1. Diesel Won’t Start Problems

  • Air leaks – vacuum in fuel supply
  • Blocked fuel supply – filters
  • Cam – crank sensor
  • Diesel injector/s bad
  • Faulty pressure regulator – sensor
  • Flat batter – low cranking speed
  • Fuel contamination
  • Glow plugs or relay fault in glow plug
  • High pressure pump bad
  • Internal engine problems
  • Low compression
  • Low fuel pressure
  • Low pressure supply pump-faulty
  • Not enough fuel supply

2. Hard To Start Diesel Engine Problems

  • Air leaks – vacuum in fuel supply
  • Bad pressure regulator – sensor
  • Blocked fuel supply – filters
  • Cam – crank sensor
  • Diesel injector/s bad
  • Flat batter – low cranking speed
  • Fuel contamination
  • Glow plugs or relay fault in glow plug
  • High pressure pump bad
  • Internal engine problems
  • Low compression
  • Low fuel pressure
  • Low pressure supply pump bad
  • Not enough fuel supply

3. Diesel Runs rough at lower RPM Problems

  • Air leaks – vacuum in fuel supply
  • Air intake restriction
  • Bad pressure regulator – sensor
  • Blocked fuel supply – filters
  • Cam – crank sensor
  • Diesel injector/s bad
  • Fuel contamination
  • High pressure pump bad
  • Injector blow-by seat leaking
  • Injector wiring harness bad
  • Internal engine problems
  • Low fuel pressure
  • Low pressure supply pump bad
  • Not enough fuel supply

4. Lack Of Diesel Engine Power Problems

  • Air leaks – vacuum in fuel supply
  • Air intake restriction
  • Bad pressure regulator – sensor
  • Blocked fuel supply – filters
  • Diesel injector/s bad
  • EGR problems
  • Fuel contamination
  • High pressure pump bad
  • Injector blow-by seat leaking
  • Internal engine problems
  • Low fuel pressure
  • Low pressure supply pump bad
  • Not enough fuel supply
  • Turbo problems – waste gate

5. Diesel Engine Knocking or Pinging Problems

  • Blocked fuel supply – filters
  • Cam – crank sensor
  • Diesel injector/s bad
  • Fuel contamination
  • Injector blow-by seat leaking
  • Injector wiring harness bad

6. Black Smoke From Exhaust Problems

  • Air intake restriction
  • Cam – crank sensor
  • Diesel injector/s bad
  • EGR problems
  • High pressure pump bad
  • Injector blow-by seat leaking
  • Injector wiring harness bad
  • Low fuel pressure
  • Turbo problems – waste gate

7. White Smoke From Exhaust Problems

  • Cam – crank sensor
  • Diesel injector/s bad
  • EGR problems
  • Fuel contamination
  • Glow plugs or relay fault in glow plug
  • Injector wiring harness bad
  • Low compression
  • Low fuel pressure
  • Turbo problems – waste gate

8. Blue Smoke From Exhaust Problems

  • Internal engine problems
  • Turbo problems – waste gate

Troubleshooting Common Diesel Engine Problems

Air leaks – vacuum in fuel supply

Air leaks allow air to enter the fuel system through connections, fuel lines, fuel system and primary filter. Most leaks are spotted between the engine lift pump and filter inlet. When the diesel engine is running correctly it creates a vacuum to pull fuel through the engines filter. When the filter clogs the vacuum will increase. This will lead to engine shutting down if it doesn’t have a self bleeding system. Use a vacuum gage to perform a test.

Low Compression

Low compression in your diesel engine will prevent heat from being produced to ignite fuel and causes hard starting. This is usually a problem with high mileage or older diesel vehicles. To troubleshoot whether low compression is the problem or not, perform a cold engine compression test. Engine compression should be around 20-35 bars or 300-500 psi. If compression is below these numbers it will start causing problems.

Low Fuel Pressure

Low fuel pressure is usually created by poor fuel supply to pump/injectors/rail or the injectors/rail are not holding fuel correctly in the system. A great way to diagnose low fuel pressure is to begin with the tank and make sure that enough fuel is available to the pump. Also make sure the pump is still delivering fuel. Loosen supply pump from rail to pump. Check you fuel delivery.

Need Diesel Engine Repair?

ADS Auto Repair is a Bosch Certified diesel repair shop located at 6835 W Chandler Blvd, Chandler, AZ 85226, right off the I-10 on the south-side of W Chandler Blvd. Our shop hours are Mon-Fri, 7:30AM to 5:30PM. Give us a call today at (480) 961-8704 for Diesel Engine Repair Service estimates or with any questions.

At ADS Auto Repair our AAA Approved and ASE Certified Mechanics stay current on latest training, technology, and equipment to diagnose and repair your Diesel powered vehicle in a timely manner with only top quality parts.  We only sell and install OEM parts that we would install on our own vehicles.

0 comments

Write a Comment

Fields with * are requierd

This site uses Akismet to reduce spam. Learn how your comment data is processed.