How to Identify a Faulty Fuel Pump: Diagnosis and Repair

All modern cars use some form of electronic fuel-injection to supply the engine with fuel. This process is the job of the fuel system and it comprises many components. A steady supply of fuel ensures the engine and other dependent systems operate optimally. The key component responsible for this job is the fuel pump.

If your car has starting trouble, or if the engine seems to be sputtering intermittently, or simply turning off or stalling, it could be a faulty fuel pump. In this blog, we will discuss the symptoms and solutions to take care of a faulty fuel pump and the diagnosis and repair work needed to keep it running smoothly.

What Exactly is a Fuel Pump?

A fuel pump is a motorised feeder that draws fuel from a car's tank and delivers it to the engine’s fuel-injection system. It is a key component that serves this system, with the fuel lines and the fuel filter being the other main parts.

The fuel pump is made up of a motor that operates an impeller which draws the fuel in. A fuel pressure regulator ensures that the fuel is supplied at the specified pressure for optimal engine operation. A fuel filter ensures contaminants and any other particles do not reach the injectors.

Types of Fuel Pump

Fuel pumps can be either mechanical or electric. Older cars used to have mechanical fuel pumps to feed the carburettor. As fuel-injection systems became more mainstream, electric pumps became the norm. Until further advancements had a different need.

Most petrol engines with manifold fuel-injection system today use electric fuel pumps that are mounted inside the fuel tank. However, modern petrol and diesel engines with direct injection require higher pressure. 

The new “DI” engines, commonly “TGDI” or turbocharged gasoline direct injection for petrol, or “CRDI” or common-rail direct injection for diesel.

These engines use a high-pressure mechanical fuel pump mounted on the engine. This ensures continuous adequate fuel pressure for their high-pressure direct injection systems. The injection pressure can reach as much as 250 bar for petrol and 2,500 bar for diesel.

Does Your Car Have a Faulty Fuel Pump? Common Problems and Symptoms for Diagnosis

How can you tell if your car has a faulty fuel pump? Here are some symptoms you need to look out for as a simple means of diagnosis.

• Starting trouble: Trouble starting the car or a longer crank duration before sputtering to life could be due to inadequate fuel pressure or volume.
• Engine stalling: If the engine runs for some time but doesn’t accelerate beyond a certain rpm, or if it sputters and stalls. It may even affect the idle speed.

• Low power: Insufficient power or driveability in situations where the car performed fine earlier, such as when going up a routine incline or partial slope, points to fuelling issues.

   

Faulty Fuel Pump – Repair or Replace?

Car fuel pumps can last for as many as 10 years or 1 lakh kilometres and even more. A faulty fuel pump could not be due to the fuel pump itself and the problem may be caused due to other reasons. Here are some ways of checking if you can avoid replacing a fuel pump.

Fuel pressure: The fuel pressure can be checked with a fuel pressure gauge at the service station to verify that it is operating at manufacturer-recommended levels. If the fuel lines are damaged, blocked or have developed a leak, it may lead to such issues.

Fuel pump function: When the car’s ignition is turned on, the fuel pump spins up to prep fuel for starting the engine. This creates a humming sound near the tank. If the sound is not particularly audible, it may point to inefficiency or a faulty fuel pump.

Fuel pump relay: All cars with electronic fuel injection use many electronic components. The fuel pump relay could be the reason for your faulty fuel pump. Have it checked and replaced if necessary.

Fuel filter: A clogged fuel filter may prevent enough fuel from reaching the pump in the first place. Although this is part of routine service, filling up low quality fuel may lead to early blockages of the fuel filter. It’s best to get it checked and replaced as needed.

Fuel injector cleaning: It is possible for tiny debris to accumulate and block the fuel injector nozzles—which are minute and sensitive—which would lead to inadequate fuel for the engine, and not because of a faulty fuel pump. Cleaning the fuel injectors will help in this scenario.

How Much Does a Fuel Pump Replacement Cost?

If there are no solutions from performing the above mentioned checks, the only solution is to replace the faulty fuel pump. Depending on the type of car and the engine size, the cost of the fuel pump assembly can be between ₹ 5,500 and ₹ 13,500. The complete set costs upwards of ₹ 38,500. Note: these prices are for Maruti Suzuki models, but apply to most popular and best selling cars in India across different segments.

Conclusion

The fuel system is the lifeblood of a car’s function. A faulty fuel pump can cause all sorts of trouble from non-starting to sputtering and stalling, as well as make the car feel underpowered. Apart from a faulty fuel pump, the car may also have similar symptoms if the fuel lines are damaged or if the fuel filter is clogged or blocked.

Sticking to the periodic service of the car is the best way to ensure continued functioning of the car. Filling up low-quality fuel, driving in dusty or polluted areas, and not maintaining tyre pressure all will lead to unplanned early trips to the service centre.