Top 4 Diesel Fuel Pump Failure Symptoms

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What are the various diesel fuel pump failure symptoms? Apparently, the function of the fuel pump system in any vehicle is the same; it regulates fuel inflow into the engine.

There are quite a bunch of other components that make up the fuel pump system; these components include the fuel injectors, fuel pump filter, and a lot of others.

If any of the fuel pump components should get damaged or faulty, apparently, the fuel pump system will begin to malfunction, and then, your car would start to display various signs and symptoms.

But how do you know if the signs you’re getting are from a failing diesel fuel pump? That is precisely what we’re going to tell you about today.

What Causes Diesel Fuel Pump Failure?

Diesel Fuel Pump Failure Symptoms

The major reason why fuel pumps fail in different cars is the lack of proper maintenance. Not everyone pays relevant attention to the fuel pump and its little components such as the injector and fuel filter.

Mostly, fuel pump failure is caused due to clogged injectors or broken fuel filters.

However, asides from improper maintenance, age can also affect the fuel pump system and its components. For example, a car of about 20 years or even older, which has been driven consistently all through these years, is likely to have many worn out, or weak components.

For such a car, if the fuel pump filter has never been changed, chances are that the filter may be damaged or clogged.

Now, it is important to say that if you do not unclog or change a faulty fuel filter, the situation is likely to lead to total damage to the fuel pump system.

This same scenario is likely to occur when one or more parts of the fuel pump system are left unattended to.

Thus, simply put, diesel fuel pump failure is usually a result of abandonment – not paying serious attention to faulty fuel pump components, and not fixing the minor issues on time.

On a quick note, before moving on to the symptoms of a failing fuel pump system, it is important to note that frequent lack of diesel in the gas tank can also cause affect the efficiency and effectiveness of your car’s fuel pump system.

When you allow your car to always run out of gas while driving, chances are that the fuel pump system, mostly the injector unit, is likely to be badly affected. Now, let’s discuss the signs you’d get when your diesel fuel pump system is bad.

Diesel Fuel Pump Failure Symptoms

The symptoms are likely to differ from vehicle to vehicle. Regardless, when you start noticing any of these common signs mentioned below, it’s time to troubleshoot your car and fix the problem on time.

1. Hard Starting or Car Won’t Start At All

When the fuel pump is bad, it’s either your car won’t start at all or you’d find it very hard to start it up.

It’s no rocket science, the hard starting is simply because your engine is not getting enough diesel to operate. In contrast, if your car won’t start at all, it means your engine isn’t getting any fuel at all.

This sign is the commonest symptom of a failing fuel pump. Regardless, it is important to note that there are other components that if faulty, could also cause hard starting. But in most cases, hard starting is caused/related to the fuel pump system.

2. Loss of Power

Another clear sign of a bad fuel pump is loss of power. When your car seems to be losing power as you try to accelerate a hill or while on top speeds.

This is also caused due to insufficient fuel supply into the engine; thus, the engine is unable to function efficiently as supposed.

3. Unusual Sputtering

Sputtering is a situation whereby you’re driving on a smooth road or path but you feel like you’re driving on a rocky surface.

Sometimes, your car may sputter for a while and then gradually die off due to lack of fuel in the engine; this scenario can be very dangerous especially if you’re on a major road or a highway.

4. Increase in Temperature (Overheating)

This may not happen in all vehicles, but a bad fuel pump can cause the engine temperature to increase, and you may notice that your car now overheats, which has never happened before.

Also, it is important to say that there are other causes of overheating – however, a bad fuel pump is one of those causes.

How To Fix A Bad Diesel Fuel Pump

We’d strongly advise that you engage a mechanic to troubleshoot your car and pinpoint the actual cause of the symptoms you’re getting. This initial troubleshooting is very important as many other situations could cause these same signs to occur.

Well, you can troubleshoot your car by yourself using an OBD2 scanner. The purpose of this troubleshooting is to ensure that, truly, the symptoms you’re getting are a result of a bad fuel pump.

If the fuel pump is still okay, your troubleshooting device will point out the faulty component that’s responsible for your car’s underperformance.

RepairPal estimates that the average cost of replacing a bad diesel fuel pump is somewhere between $1,900 and $2,000, labor cost inclusive. However, if you’re lucky and it’s just the fuel filter that got damaged, the repair mostly doesn’t exceed $150.

This is why you should act proactively whenever your vehicle starts exhibiting certain unusual signs or sounds.

Usually, most costly repairs originated as minor issues, but because they were not attended to quickly, the situation escalated to become an expensive one.


In summary, the diesel fuel pump failure symptoms are all that we’ve mentioned above. When you start to notice any of these signs, take your car to your preferred mechanic and have it checked up.

More so, the importance of regular maintenance cannot be overstated; it saves you money by helping you to identify and fix minor issues on time.

However, experts advise that you should consider changing your fuel pump after every 100,000 miles you run; how does that sound to you?

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