How to Spot the Signs of a Failing Diesel Pump

The diminutive diesel pump has a significant role to play in keeping your vehicle on the road. It therefore pays for you to be aware of the typical symptoms associated with a diesel pump that is on the way out, so you can take proper action before it fails completely. What should you be looking for?

Different Types of Pump

All internal combustion engines rely on either mechanical or electrical pumps in order to deliver fuel to the engine. Older vehicles have a mechanical pump which was typically mounted on the outside of the tank and has an internal diaphragm as its primary component. The more common electronic fuel pump is able to generate much higher levels of pressure in order to work with the more complex fuel injected engines of today. This type of pump is located inside the diesel tank itself.

What Does the Pump Do?

A pump not only delivers diesel from the tank to the fuel injector, but also it ensure that the correct amount of pressure is present at all times so that the engine gets a constant and correct supply of fuel in all conditions.

Speed Problems

If you notice that the engine is "spluttering" when driving at speed this could be a sign that the diesel pump is losing pressure intermittently. While it could be a case of contaminated fuel, a failing pump is more likely the cause.

Jerking Movement

If you find that your vehicle jerks when you are accelerating from a standstill this again could be a sign of the pump malfunctioning. It is meant to deliver the perfect amount of fuel as soon as you hit the accelerator pedal and a malfunction may be causing that flow to be stalled.

Forward Surge

Worryingly, sometimes your vehicle will appear to surge forward even though you are not accelerating at the time. This means that the motor within the diesel pump is not working properly by providing the proper amount of "resistance" to the fuel supply. Sometimes, an ageing pump will not pull enough electricity into the system in order to maintain pressure properly and this can result in this unwanted surge.

Unable to Start

Eventually, a failing pump will simply result in an engine that won't start. You may turn over the ignition and hear the engine attempting to fire, but it will be unable to as there will be no fuel available.

It's important to exercise care when changing any fuel pump as you may be working in a combustible environment. For this reason, it is better to get a qualified mechanic to do the job for you.