Understanding your car’s fuel pump

A fuel pump is a device that pumps liquid fuel from a fuel tank to the internal combustion engine.
According to Ronald Lubega of Grace Lubega Motors in Makerere, like its name suggests, your engine’s fuel pump works to move fuel from the tank to the engine. This makes it an integral part of the operation of your vehicle, and any sort of damage or mechanical malfunction in the pump can have a bad effect on your car.

Nearly all modern vehicles that use internal combustion engines come equipped with fuel pumps. The fuel pump delivers fuel from the tank to the engine at the appropriate pressure required to meet performance demands. Lubega says when the key is turned on, the fuel pump is activated and pressurised. However, he says, the fuel pumps equipped in most modern vehicles are electric pumps that are mounted in the fuel tank.

However, some vehicles are equipped with inline or mechanical style fuel pumps. Because the fuel pump is the component responsible for supplying the engine with the fuel required for it to run, any issues with it can cause major performance problems. Usually a bad or failing fuel pump will produce a few symptoms that alert the driver of a potential malfunction.

Noise
Lubega says an old or worn out fuel pump may produce a noticeably loud sound when it is running. “Pumps will produce a quiet hum during their normal operation, however an excessively loud whine coming from the fuel tank is usually a sign that there is an issue,” he says.

Difficulty in starting
This is another common symptom that is commonly associated with a problematic fuel pump. Lubega says because the pump runs constantly, whenever the ignition is turned on, over time the fuel pump can eventually wear out and weaken. He adds that a weak fuel pump may still pump fuel, however the vehicle may experience difficulty starting because there is no pressure. A weakened fuel pump can cause the vehicle to take more cranks to start than normal, and in more serious cases may even cause the vehicle to require multiple turns of the key before it starts.

Misfires and a decrease in power
Another symptom of a problem with the fuel pump is issues with engine performance. Lubega says as the fuel pump is what supplies the vehicle with the fuel required for combustion to occur, any issues with it can affect the engine’s fuel supply and cause issues. A faulty pump with low pressure will disturb the engine’s air-fuel ratio, which can cause a number of performance problems. Aside from hard starting, the vehicle may experience misfires, a loss in power and acceleration, a decrease in fuel efficiency, and even engine stalling.

The car might not start at all
According to Bosco Kigongo, a mechanic at Icony Garage in Kinawataka, this is a more serious symptom of an issue with the fuel pump. Bosco says if the fuel pump fails completely, or to the point of not being able to provide enough fuel for the engine to run, the vehicle will experience a no start condition. The engine will still crank when the key is turned, however it will be unable to start due to the lack of fuel. However Bosco says a no start condition can also be caused by a wide variety of other issues, so having the vehicle properly diagnosed is highly recommended.

Faulty fuel pressure gauge
Bosco Kigongo, a mechanic at Icony Garage in Kinawataka, says the fuel pressure gauge can show conclusively that the pump is not delivering the right amount of fuel to the engine. He adds that the driver can check the gauge while someone else is revving the car to a given speed. Looking at the owner’s manual will also show how much pressure should be exerted if the pump is operating properly. Anything less is indicative of fuel pump problems that require attention.
He advises that understanding the warning signs associated with a failing fuel pump can help you notice the problem early. Once you notice the symptoms of a flawed fuel pump, ask a mechanic to inspect and replace it before it fails completely or causes more damage.

Do not just replace the pump
If your vehicle’s fuel system is at the point where fuel pump replacement is necessary, it may make sense to swap out other important components at the same time. A bad fuel pump means that your fuel filters are most likely clogged, and you might want to think about having your fuel injectors cleaned. However, don’t let the cost of the maintenance spiral out of control.

Reasons your fuel pump might fail

Fuel pumps are found on virtually all internal combustion engine equipped vehicles in one form or another. Bosco Kigongo, a mechanic, says although most fuel pumps are built to last, over time, as the vehicle’s mileage builds up, the car’s fuel pumps might require replacement.
He adds that another reason fuel pumps fail is if you regularly keep less fuel (a quarter the tank’s capacity) in the car. Kigongo says this leaves the pump struggling to keep up with its duty and in the end it develops issues. Kigongo advises drivers to always keep at least a quarter of the capacity of the fuel tank.

He points out other reasons including contamination, overheating of the fuel tank and the gears in the fuel pump wearing out over time. “Rust, debris and dirt are three common particles that can somehow enter the fuel tank and get fed towards or through the in-tank fuel filter and possibly into the fuel pump,” says kigongo.

He adds that drivers should make sure the fuel tank is protected and free from any particles because they clog your fuel pumps filter, making it work harder to pump fuel. This causes stress and accelerated wear on the several small components inside the fuel pump, eventually leading to fuel pump failure. Your car’s fuel pump relies on fuel running through it to cool and lubricate it. Starving your fuel pump of fuel can cause it to fail prematurely.

Cost of fuel pump replacement
According to Ronald Lubega of Grace Lubega Motors in Makerere, the cost of replacement of the fuel pump will depend on a few issues including ones’ relationship with their mechanic and the mode of payment.
“For small SUVs such Toyota Spacio, a fuel pump will range between Shs60,000 and Shs80,000. For larger cars, the price might go up to Shs150,000,” he says. For replacement, Lubega advises drivers to take the car to a certified and tested mechanic especially those who have expertise in car wiring.

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