Fuel, misfire and misconception

Posted on Wednesday, April 21 2010 by Mark Rothwell

Fuel, Misfire, and misconception.

High pressure, common rail engines have been forced upon us due to emission legislation and agricultural engines and machinery have developed problems, sometimes at low machine hours, due to lacquering and carbonisation of the fuel and emission regulatory components. This problem causes misfire, uneven running, “lights” flashing and in extreme cases component failure.

 So I’d like to cover briefly this subject, explain some background to the issue and offer some prevention tips and cures.

Fuel! At the moment this is the root of all evil to you. Speaking to members of the farming community, I have realised that many are under the misconception that what they are buying is merely road (white) diesel with a dye in it - but its not. Red diesel is less refined, has a higher sulpher content (up to 1000 parts per million), has a lower cetane level and a higher moisture content. So what does this mean to you?

• high sulpher level causes carbonisation
• low cetane level causes poor combustion, low performance
• moisture causes bacterial growth in fuel and oxidisation, which causes lacquering of the system, a breakdown of the fuel when under extreme pressure. The fuel actually 'shears' - you can see the evidence of this when you remove a filter and find a dull sludge sat on the top of it. This is caused by bacterial growth.

So how can we prevent and cure this problem?

A clean, moisture and debris free supply, regularly changed is the most important start.  But if you have an older tank, when it’s low, remove it, clean it and fill with fresh fuel. Ordering a lower amount more regularly will result in cleaner, fresher moisture free fuel.

We can add an additive to the machine. This cleans, lubricates and helps to maintain the system. You may see this as additional cost but tests have proved that regular use results in a more efficient engine which uses less fuel and more than covers the cost of any additive. It also lowers the temperature at which your diesel will gel in cold weathers, and raises the cetane level.

And lastly – when we do have reached the point where we have problems, what are the options? The biggest single cost is if left unmaintained is that the injector nozzles will block due to carbon and lacquer. This could mean replacement of injectors, pumps and valves at huge cost. We now can offer an in situ injector cleaning service, this costs around £180-£200, including the cleaner, filter and labour. This de-lacquers the system, clears carbon deposits and in 95% of cases cures all faults and straight away you will see a noticeable improvement in the running and performance.

This is also done at half the cost, and at a scheduled time when you take out a John Deere maintenance contract.

Maintenance contracts are something we should all look at as the price is now far more viable than in previous years, and with escalating prices of everything these days it’s nice to future price everything possible and know your fixed costs. Certainly something to consider, why not call us for some further info.

Thanks for reading.

Mark Rothwell,

Service Manager.