What You Need to Know About Common Fuel Injection Pump Issues

Diesel engines are comprised of several key components. One of them is your fuel injection pumps. These specific components are closely tied to overall engine performance and can lead to serious engine trouble if there’s a fuel delivery problem. Thus, injection pump issues need to be addressed as soon as possible. The good news is that any significant engine repairs tend to involve an overhaul of your injection pumps—just as a precaution. That said, remanufacturing or replacing injection pumps is generally a quick fix that will ultimately improve your vehicle’s performance and allow for a smoother ride. How do you know if it’s time to replace or repair your fuel injection pump? Well, typically, there are a few telltale signs.

Injection Pump Overview

Before getting into the most common fuel injection pump issues, it’s beneficial to understand why properly functioning injection pumps matter so much. Simply put, fuel injectors supply your engine’s internal combustion chamber with fuel. Typically, vehicles have one fuel injector per cylinder, and fuel is dispensed from the pump to a chamber. This occurs via a fairly straightforward process that allows pressurized fuel to enter the injector, then pass through a solenoid valve into a plunger, and eventually leave the fuel injector as a fine mist (a spray tip distributes this mist).

Common Pump Problems

Though this process is seemingly uncomplicated, there are still a lot of things that can and do go wrong. More often than not, diesel fuel injectors fail due to faulty mechanical problems or fuel issues (poor quality, lack of fuel, and others.). If you haven’t experienced a complete injection pump failure, then there are likely several other specific problems that may require fuel injection pump repairs or replacements. If your injection pumps need to be replaced, it’s highly recommended that you should install brand-new Stanadyne injection pumps, instead of used or remanufactured pumps. This will ensure a better performance overall.

Dirty Fuel Problem

A typical problem that occurs with fuel injectors is a build-up of dirt or residue. This is a fairly common issue because overtime gunk, grease, and grime can clog up a fuel system, especially in areas like the spray tip. Moreover, older diesel engines tend to experience this issue more often, especially 2006 model engines. Diesel fuel production was altered in 2006 to compensate for ultra-low sulfur diesel fuel (ULSD). If you have a newer diesel engine, i.e., a 2007 model or older, the build-up will still occur, but definitely not at the same rate as ULSD-accommodating engines. Thankfully, ULSD fuel was mandated and phased out in 2007, so hopefully, in the last 13 years, you’ve had your pumps replaced or thoroughly cleaned out at least.

Low Fuel Tank Level

Yet another issue that leads to trouble for your injection pumps is consistently maintaining a low fuel level. Your engine needs to be adequately lubricated, ideally at all times. If there’s not enough diesel fuel in your tank, your pumps will essentially be pushing out air instead of much-needed fuel. Furthermore, the fuel that your engine does receive won’t be pressurized to the appropriate level. Thus, it’s no surprise that this is honestly one of the quickest ways to destroy or damage your fuel pump injectors.

Weak Engine

Besides fuel issues, your engine itself can cause irreparable damage to your injection pumps and vice versa. If your motor is older or simply on its last leg, then it could very well cause your injectors not to work properly. A clear indication that you have a weak engine is poor acceleration. For example, if you have to push your engine to its breaking point to get your vehicle to speed up, then it may be time to consider a new engine.

Misfire and Running Issues

Similarly, if you’ve noticed that your engine has been misfiring, there’s a strong likelihood that your fuel injectors are having issues. Typically, if your injectors are the culprit, then the amount of fuel that’s being supplied into the engine is probably incorrect. Again, this is another issue that could cause serious damage to your engine over time, so it’s vital that you address an engine misfire sooner rather than later. Along those same lines, if you’ve noticed your vehicle isn’t running smoothly or has difficulty starting, it’s likely time to inspect your injection pumps and ensure that your engine is getting the fuel it needs.

Bad Timing

Your fuel injectors are also susceptible to bad timing. Generally, this problem stems from a common pump glitch—defective fuel injector’s O-rings or ball seats. Faulty O-rings or ball seats disrupt the fuel transfer process. If this happens to be the case with your injection pumps, you’ll likely need to replace or rebuild your pumps.

Smoky Exhaust

One of the most common problems, or rather, signs that your injection pumps are struggling is a smoky exhaust. Though many mechanical issues can cause a smoky exhaust, you can pretty much guarantee that your fuel injection pumps are dirty, or not working as well as they should.

Foreign Objects

Lastly, to have your diesel injection pumps running smoothly, they must be free from foreign objects or debris. Foreign objects, such as dust or some other microscopic fragments, can easily clog your injector. Even worse, foreign objects can cause your injectors to stay open, eventually effecting your engine’s cylinder performance.

Final Note

Ultimately, you can avoid many of these common fuel injection pump issues and problems by properly maintaining your vehicle. This means buying clean, trustworthy fuel, changing your filters as required, keeping your tank at least half-full if possible, and servicing your car or truck when you know for certain something is wrong. With that said, adequate vehicle maintenance also includes replacing or rebuilding key components to your engine. Therefore, if you believe you need a new fuel injection pump, then start shopping for one.


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