Diesel Engine Fuel Pumps Explained

How much do you know about diesel engine fuel pumps? This part is one of the most vital components, allowing for combustion to occur. 

There are several different kinds of fuel pumps, including rotary, inline, and high-pressure common rail. In this post, we're going to take you through each of these and some signs to look out for if your pump is failing. 


If you have a failing fuel pump, give us a call. Our ASE Certified Tech can help you get the right pump for your diesel engine!

Give Us A Call!


How Do Diesel Engine Fuel Pumps Work? 

While each type of fuel pump works a little differently, they all serve the same purpose—to move fuel through the system and into the combustion chamber. The three types of fuel pumps we're covering today are: the rotary pump, the inline pump, and the high-pressure common rail pump. 


Rotary Pump


p274025r rotary pump group | Highway & Heavy Parts


As you might gather from the name, a rotary pump has more of a circular design. The output lines are positioned in a circle, and it has a distributor. This distributor is turned by a drive shaft. There are different types of rotary pumps you might see, including ones that are electronic. These are often found on older engines. 


Inline Pump


p276385r inline pump group | Highway & Heavy Parts


An inline pump is a bit different from the rotary pump. Where the rotary pump has the output lines in a circle, and inline pump has them all in a straight line. Unlike other types of fuel pumps, each cylinder on an inline pump operates on its own, also allowing them to fail separately.


High-Pressure Common Rail Pump


p274464r common rail pump group | Highway & Heavy Parts


 A high-pressure common rail pump has a bit of a different design from the rotary and inline pumps. It is more similar to the HEUI oil pump. 

A high-pressure common rail pump has revolving pistons, as well as one inlet and one or two outlets. In this design, the outlets are connected to a rail that supplies the pressure to the system. With an inline or rotary pump, you're getting a specific amount of pressure applied every time. A common rail pump lets the rail handle the pressure and the ECU takes care of the fuel distribution. 

Are you having problems with your John Deere fuel pump? Check out our post featuring reman diesel engine fuel pumps for John Deere engines!


Failures Associated with Diesel Engine Fuel Pumps

When you experience a failure in your diesel engine, you want to quickly identify the issue to get back up and running. Depending on the type of fuel pump you have, you could see different issues that point to a failing fuel pump.

If you have a rotary pump on your engine, you might see:

  • Hard start
  • No throttle control
  • Seized head
  • Plugged nozzle
  • Fuel contamination
  • Fuel in the oil
  • Fuel leaks
  • Wear from ultra low sulfur

Failures on an inline pump include:

  • Fuel in the oil
  • White, black, or blue smoke
  • Low power
  • No start
  • No RPM
  • Cylinder not pumping
  • Wear from ultra low sulfur

With a high-pressure common rail pump, you could experience:

  • The pump quitting entirely
  • Wear from ultra low sulfur
  • Failed pressure regulator
  • Engine goes into limp mode under load
  • No start

There are other kinds of diesel engine failure that might produce similar symptoms. That's why proper diagnosis is the key to any repair. 

Think you might be having trouble with a different fuel system component? Read our post explaining diesel engine fuel injectors


Fuel Pumps from Highway & Heavy Parts

If your fuel pump fails, you want to make sure you're putting the best quality part in your engine. That's where Highway & Heavy Parts comes in!

We know that with the tight tolerances and moving parts, diesel fuel pumps have a lot of failure points. Poor fuel system maintenance and the use of contaminated diesel fuel can wreak havoc on all the sensitive fuel system components, leading to expensive repairs.

HHP takes the risk out of buying parts! We only sell fuel system components that are built by reputable, OE-certified manufacturers that use the latest OE-approved diagnostic, calibration, and testing equipment available. Not only does this ensure that your fuel pump is manufactured to meet or exceed original OEM specifications, but it also is going to be the same pump your engine was built with. 

With a fuel pump from HHP, you'll be getting reduced noise, higher torque, lower emissions, and better fuel economy than you would with a lesser quality pump from a non-OE supplier. 


If you  need a fuel pump or any other diesel engine replacement part, we can help you find the right fit for your engine! Give our ASE Certified Techs a call at 844-304-7688. Or, you can request a quote online.

Comment Post Comment