What is the fuel system/what does it do?

The fuel system is vital to your vehicle and whilst it can vary from vehicle to vehicle, its role in each vehicle is the same - to store and distribute the fuel to your internal combustion engine in order for it to run.

Getting into the details of the fuel system

One of the primary elements of a fuel system is the fuel tank. Whilst it may seem obvious, a fuel tank holds the fuel in your vehicle and is filled by the driver at service stations using a filling station pump. The fuel tank usually has a sensor inside which tells the fuel gauge how much fuel is in the tank and the tank is also designed to minimise the amount of hazardous vapours escaping the tank. The fuel tank is located on the opposite side of the vehicle to the engine for safety reasons.

The fuel system also has a fuel pump attached either to the fuel tank in newer models, or to the engine in older vehicles. This pump is operated either by the car electrics or by the engine depending on where it’s located. This fuel pump is attached to a pipe which draws petrol out of the fuel tank. This fuel pipe has a filter in it to take out any imperfections in the fuel. Good maintenance of the fuel filter is essential as any imperfections such as paint chips or dirt will cause the running parts of an engine to wear more quickly.

In some older vehicles this fuel is then sent to the carburettor to mix the fuel and air in correct proportions. Nowadays, it’s much more common for this to be mixed in the engine itself with fuel injected in to the engine chambers and mixing with air generated by the pistons.

What if something goes wrong with the fuel system?

Problems with the fuel system can cause major problems with the engine. Some issues can include excessive engine smoke or difficulty with the engine starting or loss of power. These are obvious signs that something is wrong, and should be investigated immediately.

The most common failure in a fuel system is the fuel filter, which is prone to clogging. As mentioned earlier, this is key to ensuring that the fuel in the vehicle is clean and suitable for your engine. It’s therefore recommended that these are changed regularly at about 15,000 miles to ensure that the fuel is clean and the engine runs efficiently.

Dirt deposits can build up on the fuel injectors even with a properly working fuel filter and clog them causing either not enough fuel being injected in to the combustion system or too much if the injectors are stuck open. It’s possible to prepare for this issue by using a fuel system cleaner regularly in your vehicle to minimise the chances of injectors becoming clogged.

Electric fuel pumps are also prone to failure. You should be able to hear an electric fuel pump start up when you start the vehicle, so being unable to hear this isn’t a good sign and should be checked as soon as possible. These pumps are powered by a relay, so it could be possible that this is the issue.

Other problems relating to the fuel system can be caused by putting the wrong fuel in the vehicle. This could be because the driver is unfamiliar with the vehicle, perhaps because it’s new or a rented vehicle. If you’ve put the wrong fuel in your vehicle don’t use it and calculate the amount of incorrect fuel you’ve put in the vehicle. You should then contact a reputable garage immediately for repair.