Diagnosis and Repair of Advanced Diesel Injection Systems.

4WD Specialist and Diesel Services comes into play when the diesel injectors have build ups Diesel injectors are not that prone to developing build-ups but if that happens 4WD Specialist and Diesel Services are very necessary. Dirty injectors, missing on start-up, poor running, and loss of power, increased fuel consumption and exhaust smoke are the symptoms which are usually not related to injector deposits.

About Diesel Injectors

Diesel injectors operate at a very high pressures and this helps to keep them clean but it also means that they wear out in time. Wearing out with time leads to the need of replacing their nozzles at regular intervals.

The part of the diesel injectors and pumps are usually not serviceable. It is a good idea to only replace the fuel filter yourself. Always see the mechanic for other concerns in your vehicle. Most general repair workshops often send the whole vehicle to a diesel injection specialist for repair. They may sometimes remove the fuel system parts and send them out for repair.

The chemical cleaners cleans a dirty fuel system. They may loosen build-ups resulting in on-going fuel filter blockages, or other problems. They are not efficient enough to restore a worn injector or to overcome a mechanical problem in the engine. Only cleaning may not fully resolve the issue. Eventually, a proper repair may still be needed.

Other issues

Mainly normal wear and tear and other basic engine maintenance issues are the cause of many engine performance problems.


Check the below basics first:

  • Tappet adjustment can cause rough running, poor performance, and increased exhaust smoke. Check it.
  • Low or uneven compression also produce same symptoms.
  • A worn engine will not perform properly so it is worth considering the general condition of the engine. A compression test may help to determine this. A worn engine could still show satisfactory compression on the devices and tools, we need to be aware of this.
  • A common cause of poor performance and excessive smoke is blockage in air cleaners. Check for it.
  • Check for a blocked fuel filter.
  • If the engine doesn’t start cleanly or if it is hard to start then check the glow plug operation. It is possible that not all glow plugs are working which causes the engine to start initially on only some cylinders. Fuel drain back can also result into similar symptoms.
  • Check for engine management system faults. We need specialist knowledge and test equipment to diagnose if the engine light illuminates properly or not.
  • When DPF warning lights are illuminating frequently it is possible that the DPF system is at fault. Drive the vehicle far or fast enough to allow regeneration to occur.
  • The use of the wrong oil can produce performance problems so better use the right one. The correct engine oil grade is of paramount importance.

Safety Warnings

  • The diesel fuel systems operate at a very high pressures so there is a risk of serious injury or death from contact with high pressure fuels.
  • Removing an injector and starting the engine to check its spray pattern is dangerous.
  • There is risk of severe electric shock because some electronic diesel injectors work on high voltage which is around 150 volts.
  • Single use fuel pipes commonly used in rail fuel systems must be replaced when loosened as they cannot be reliably resealed.
  • Since the electronic injectors are calibrated to the engine management computer hence they must be refitted into their original place. The system must be re-calibrated using special equipment if the injectors are overhauled.

Avoiding fuel system problems

You can follow the below steps to avoid unnecessary problems.

  • Buy fuel from a well-known brand and from a reputable source, even if it costs a bit more. An injection system will be quickly and completely destroyed by a dirty, poor quality or contaminated fuel.
  • Always keep a record of your fuel purchases in the form of receipts. You will be in a better position to negotiate some assistance from the supplier if you get a bad or contaminated batch.
  • Always use clean, dry, sealable and fuel safe containers to keep the suspect fuel. Keep at least 1 litre of it. The company involved may want it for testing and they may ask for it.
  • Be mindful of the need for regular replacement of the fuel filter as it is there to protect the fuel system. More frequent filter replacement may be necessary if operating under adverse conditions.
  • Always fill in the dry weather and not in the rain. This is to reduce the possibility of introducing dirt and water into the system. Always clean dirt and dust from around fuel fillers.
  • Regularly drain water traps, where fitted even when the warning lights have not appeared.
  • Rain and dirt can promote algae growth. So always make sure that you do not expose the storage tanks to rain and dirt.
  • Avoid filling from drums as this greatly increases the chances of introducing contaminants.

Some Suggestions

  • Many involve chemical cleaning products.  Try them if you like. But it not a surprise if they don’t fully resolve the problem, if at all.
  • Don’t add petrol to the tank.  It can do damage.
  • Diesel injectors are pieces of precision equipment. Dismantle and clean them at your own risk.
  • Don’t attempt to replace nozzles unless you have the equipment needed to calibrate opening pressures.  You might get away with it, but you may also wreck the engine.

DPF Cleaning and Re-generations.

Diesel particulate filters or DPF are installed in most modern diesel engine powered vehicles made since 2005. They trap the soot produced by the burning diesel which results in a cleaner exhaust. They regenerate itself or self-clean itself by burning off the collected soot at set intervals. This self-cleaning process prevents the DPF filter from blocking.

Once the clogging is over the blockage limit the car may go into limp mode. This flashes the critical DPF warning lights on the dash or result into reduced power of the vehicle. The blocked filter generates a lot of heat and the temperatures can raise from 600 to 700 degree centigrade. This is a protective mechanism for the engine to protect itself from fire.


Challenges with the DPF filter

Over time the DPF filter will become extremely blocked if this warning is ignored and the vehicle is driven as normal. Because it just keeps filling up with soot. Eventually, it may becomes very difficult to clean or not possible at all. It can damage the turbocharger and engine which can be expensive to repair. Get this issue rectified by a specialist soon as you get this warning.

Use the correct low ash engine oil with the correct specification. If the oil does not meet the specification, it produces excessive ash which will clog the filter over time.

All the sensors, valves and associated components which are used to monitor the diesel particulate filter operation should be fully operational.

To initiate the regeneration process, it is important that you take your vehicle on a continuous freeway drive of over 15 minutes at the minimum speed of 80kph (or at the speed stated in your owner’s manual) at least once a week, if you mostly do short distance city driving.

When you have a problem

The filter has to be cleaned manually by putting it into the regeneration mode if it becomes too blocked for an automatic regeneration process. We do this by using our specific diagnostic software and our proven and tested on car DPF repair methods.

There are many other possible issues to repair before this can produce a lasting solution like faulty sensors, egr valves and others.

Just cleaning or replacing the DPF filter is a waste of time and money. The root cause of blockage in a vast majority of cases needs to be rectified correctly.

To book your next service or for more information on our Services and Mechanics in Truganina, Victoria, you can contact us on +61 426-533-774. We at Western Prestige Auto are proud of ourselves as we fulfil our commitment to delivering world-class services in Truganina, Victoria.


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