Bad Diesel Pumps: What are the Causes and Signs?

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Cars Are Fun to Drive and Maintain If you don't know how to drive or if you are afraid of opening up the hood of your car so you can tinker with the engine, you are in the right place. I started this blog because I don't want anyone to miss out on the fun of maintaining and driving their own auto. I am not a professional and I don't work in the automotive industry. However, for the past 10 years, I have been repairing and driving cars as I have travelled around Australia. I hope that the words I have written here will inspire you to get involved with your car.




Do you wonder why buses and trucks prefer diesel to petrol engines? Well, there are a couple of reasons for this. First, diesel engines deliver more mileage compared to their petrol counterparts. This means that a vehicle with a diesel engine will cover a longer distance than one with a petrol engine would with the same amount fuel. For your diesel engine to function effectively, it needs a good pump to move fuel from the tank to the engine and other parts. The following piece will help you understand the causes and signs of a malfunctioning diesel fuel pump:


Inadequate Fuel Pressure

Regulating fuel pressure is one of the most important roles of a diesel fuel pump. If the pump does not function properly, the vehicle cannot maintain the required fuel pressure. You will notice trouble starting the car even when the parts of the engine are working correctly.

Abnormal Sounds

Diesel engines always try their best to notify you of any mechanical malfunctions in good time so that you can act appropriately. If your diesel fuel pump isn't working correctly, you will notice strange sounds originating from the location of the fuel pump. In most cases, the fuel pump sits close to or inside of the tank. The noise you hear from this area may range from high-pitched to scraping sounds depending on the make, size or configuration of your vehicle's engine.

Malfunctioning Filter

In diesel engines, the filter works hand in hand with the fuel pump to ensure proper supply and distribution of fuel in the system. The filter struggles to deliver whenever there is a problem with the pump. It has to overwork in an attempt to draw adequate amounts of fuel. Frequent replacements of the fuel filter (could be as bad as a daily basis) is an indication that you are running on a rogue fuel pump.


There are a number of things that can lead to mechanical problems for your diesel fuel pump. These include the following:

Persistent Low Levels of Fuel – don't be one of those drivers who run their vehicles on low fuel levels. It's bad for your diesel fuel pump. The pump needs high amounts of fuel in the fuel tank to maintain high levels of efficiency. Always refill your tank whenever you see the 'low fuel' warning sign.

Engine Failures – problems with your engine often end up badly for your fuel pump. Carry out regular, timely maintenance for your engine to keep the pump in good shape. 

For more information, contact a mechanic or car service that specialises in your type of fuel pump, like Denso authorised dealers.

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