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Checking fuel pipes

Any fuel leak, however small, can cause a fire. Do not drive a car with a suspected leak until you have cured it. Never leave a car dripping petrol where a passer-by may throw a cigarette end under it. A small fire extinguisher, fitted where you can get at it quickly, is a valuable accessory. Read more

Cleaning fuel-pump filters

A blocked fuel-pump filter will cause the engine to cut out intermittently, particularly at high speeds, and it may stop altogether. Read more

Checking a mechanical fuel pump

If a car stops and has not run out of petrol, check whether there is petrol in the carburettor. If there is not, there is a fault in the fuel system. Read more

Checking and replacing a fuel sender unit

An empty tank can be more of a risk than a full one. There is always petrol vapour in it - even if it has been empty for months which the slightest heat or spark can explode. Read more

Servicing a mechanical fuel pump

Do not clamp a pump in a vice to dismantle it — the pressure could break the alloy casting. Read more

How a fuel injection system works

For the engine to run smoothly and efficiently it needs to be provided with the right quantity of fuel/air mixture according to its wide range of demands. Read more

Tuning the engine with a colortune plug

Although some experienced mechanics can tune a car's carburettor fairly well by ear, to do the job really accurately you need the help of special equipment. Read more

Servicing the fuel supply system

The fuel supply system is generally reliable and any problems that do occur are usually traceable to the pump, the fuel filter or the tank. Occasionally, however, the fault lies in the fuel line between the tank and the engine. Read more

How car oil is refined

The fuel used in a modern car, whether petrol, diesel or even LPG (Liquid Petroleum Gas), has to meet high standards of purity if the car's engine is to run smoothly. Read more

How the fuel system works - fixed-jet carburettors

The fixed-jet carburettor resembles the simpler variable-jet type (See How variable-jet carburettors work) in having a venturi - a constricted neck - through which air flows on its way to the engine. Read more

Lean burn engines

In an ideal, 100 per cent efficient internal combustion engine, the fuel would burn to give just carbon dioxide and water vapour. In practice, of course, engines are far from efficient and the combustion process. also produces carbon monoxide, oxides of nitrogen and unburnt hydrocarbons, as well as carbon dioxide and water vapour. Read more

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