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Posts Tagged ‘Diesel engine problems’

How clean is the diesel fuel in your tank?

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How clean is the diesel fuel in your tank?

“how clean is your fuel and if it is dirty what can you do about it?”

diesel fuel with dirt

Contaminated diesel fuel

We assume that fuel sold at the pump will be clean enough not to damage the engine

Unfortunately this is not always the case your fuel could be dirty and
here are some of the reasons  why:

  • crude oil it is getting scarcer so manufacturers are getting less fussy which oil they use.
    As demand continues to rise this problem will most likely get worse.
  • refining technics sometimes mean quality is sacrificed for quantity.
    The use of certain refining techniques produces high quality gasoline(petrol/essence) but
    lower quality diesel.
    Nowadays most diesel fuels are low sulphur.
    This is good for the environment but not so good for the diesel because
    ironically it reduces the lubricating quality of the fuel.  Unfortunately diesel injection equipment relies on the fuel passing through it to lubricate it at the same time
  • blending – modern blending techniques can reduce the lubricating properties of the diesel fuel

why is clean fuel so important?

High pressure components

The most important components in your diesel engine are the  high pressure pump
and  the injectors.  The components inside of these need to move freely.
Dirt in the form of sediment, bacteria wax and rust can cause them to stick.
The injectors spray a fine  pattern of fuel into the engine the holes in them are only microns wide so any blockages will cause a malfunction of the injector.

holes in diesel injector nozzle

Spray holes in nozzle

So what can you do about dirt and contamination?

here are 2 strategies to extend the life of your engine  and hope it perform better

1. Strategy number 1
fit a primary diesel fuel filter you will need to fit it up-stream of the existing fuel filter
so it goes between the existing filter end of the fuel tank

now you will have two fuel filters
so proper filtration is the number one strategy you can employ.
This is especially important if the fuel you use is likely to have dirt and water in it.
Check out the top quality filter systems like Fram and Stanadyne

2. Strategy number 2  reduce the impact of water and dirt already in the fuel.
your diesel system has precision components and their greatest enemy is  water

Unfortunately there is usually water in diesel fuel
and if it gets into the system it will cause rust, corrosion and wear.

In addition to all this  modern common  rail diesels work at much higher pressure and finer tolerances
than earlier diesel engines.
Water is usually emulsified into the diesel like oil and vinegar in a salad dressing
ideally you need to demulsify the water so the filter can remove it efficiently.

Search on line for good quality, proprietary brands of demulsifying solutions or visit your local diesel shop. 

Diesel engine problems

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Solve your diesel engine problems with these easy checks!

Make Your Car Start and Run Better and Go Further


diesel engine“My car is difficult to start and it seems to have lost power!”

DIfficult starting and loss of power are among  the most common  diesel engine problems people get with their cars.


Check for:

  • Air leaks in pipes and connectors.
  • Pay close attention to air intake pipes, mass air flow meter and turbo connecting pipes.

Check for:

  • Dirty or clogged filters.
  • Diesel fuel is contaminating so regular maintenance is important. diesel engine air filter
  • Main filters to change are Fuel, Air and Oil. Fuel contains impurities so fuel filter maintenance will minimize this.
  • Change oilf filter on a regular basis to reduce engine wear to a minimum.
  • Diesel engines rely on compression to function ; clean top quality oil will keep the engine running at it’s best.

Some engines have extra filters (eg BMW diesel ) check service manual for these.

Check for:

diesel engine injector nozzle

  • Worn and/or sticking injector nozzles. Diesel injectors  give very good service overall but will eventually require replacement.
  • Common rail diesel is quiet and effeicient but is operating at very high pressure so expect to change injectors when mileage passes 100k mark (this figure will vary depending on maintenance, driving style etc. )

Check for:

  • Electrical connexions. Modern diesels are electronically controlled so electrical connexions are very important. Always check for electronic faults if you have diesel engine problems.

Check for:
Problems with the turbo.

  • Modern turbos are under pretty savage operating pressure.

Due to increasing demand for more power from smaller and smaller engines and ever  stricter emission controls turbos are spinning at high revs.

  • They are also under electronic control and this can give problems.

Diesel engine problems often involve faulty sensors or regulators.

Check for:

  • Common symptoms of sensor or regulator failure are engine cutting out regularly and unexpectedly. It will usually start OK.
    Also engine will usually run OK when under load but cut out when no throttle.

If car fails to start EOBD check is best course of action.
Diagnostics will often show fuel pressure sensor/regulator problem.

Diesel engine problems  in older cars involving difficult starting 

Check for:

  • Defective glow plugs. Indirect diesel engines are fitted with glow pluglow plug diesel enginegs for cold start. Difficult starting may be down to one or more defective glow plugs.


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(c) Andy Hewing B.Sc. February 2010