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Common Diesel Fuel Injection Pump Problems

Common Diesel Fuel Injection Pump Problems

Fuel injection pump performance is closely tied to engine performance. If your vehicle has a fuel delivery issue, it will literally starve to death. Fuel injection problems, therefore, are one of the most pressing engine issues to deal with. Whether you’ve experienced fuel injector failure or not, it helps to understand the fuel injector pump, how it relates to engine performance, and also how diesel fuel injection pumps differ from traditional gasoline-powered units.

Diesel Fuel Injection Pumps – Quick Overview:

So what does a diesel fuel injection pump do? It’s about as simple as you can get: fuel injectors supply fuel to the engine’s internal combustion chamber. High-performance automobiles usually have one fuel injector per cylinder, and the pump “injects” fuel into the combustion chamber – hence the name “fuel injector.”

The fuel is dispersed from the injection pump to the combustion chamber via a fairly simple process. Pressurized fuel enters the fuel injector. Based on a signal from an electrically controlled solenoid valve – the solenoid valve acts as a type of on / off valve – the fuel enters a plunger, which prepares the fuel for the final exit. When the fuel leaves the fuel injector, a spray tip distributes the fuel as a fine mist.

Pressure-Packed Fuel Injection:

Today’s diesel fuel injection pumps are under pressure – even more pressure than what was once considered “normal.” Around 15-20 years ago, it was common for fuel injector pumps to process fuel in a system at around 10,000 to 15,000 psi (pounds per square inch). But that’s only about half of what engines are expected to do today. Fast-forward to the present day, and those diesel fuel injector pumps are operating in the 30,000 to 40,000 psi range.

Top-end engine performance is in many ways dictated by how much fuel can be processed by the engine. Basically, a superior engine can process fuel and air better than an average engine – that’s one reason why turbochargers are so effective at increasing horsepower – and a greater internal pressure in a necessity. That helps explain the significant pressure output of today’s fuel injection pumps compared to those from yesteryear.

Reasons that explain Fuel Injector Pump Failure:

99% of diesel fuel injector failure can be traced to two different issues –

  • Faulty mechanical problems in the physical fuel injector housing
  • Fuel quality (or rather, lack of quality)

From these two things, a host of problems can surface. Let’s take a look at 4 common fuel injector pump complications.

Problem #1 – Dirty Fuel:

A clean diesel fuel pump injector is a happy diesel fuel pump injector. Over time, residue can build up in the fuel system, and enough gunk, grime and grease can clog up the entire fuel injector pump. The spray tip (where the fuel leaves the injector and enters the combustion chamber) is particularly prone to “backing up,” so to speak.

If your engine has ever sputtered or hesitated during acceleration, a clogged fuel spray tip might be the glitch. And it all starts with subpar diesel fuel. In 2006, diesel fuel production was tweaked to compensate for ultra-low sulphur diesel fuel (ULSD), and diesel engine owners have noticed more “dirty fuel” difficulties than before.

Problem #2 – Low Fuel Tank Level:

If your main goal in life was to destroy diesel fuel pump injectors, you’d run your car with the fuel tank as close to empty as possible. It all has to do with lubrication. With plenty of diesel fuel in the tank, the fuel pump bearings receive plenty of lubrication. With a near-empty tank, the fuel system is suddenly pushing air instead of diesel fuel. Anything but diesel fuel can wear out the fuel pump bearings, which means the fuel injectors will not receive the fuel at the pressurized level (30,000 psi, 40,000 psi, etc.) it should be.

Problem #3 – Foreign Object inside Injector:

Diesel fuel pump injectors are high-precision components. They also deal with a tremendous amount of motion and other stresses. One small visitor inside (a piece of dust, debris, etc.) can clog the injector. Worse yet, a microscopic object can leave the injector open all the time. If the injector can’t close, cylinder performance is compromised.

Problem #4 – Bad Injector Timing:

Whenever the fuel injector pump’s O-rings or ball seats are defective, the timing of the fuel transfer process is disrupted. This is a common diesel fuel injector pump glitch, and usually requires a complete injection pump rebuild or replacement.

Maintenance Reminder:

Here’s the good news about fuel injector pump problems: avoiding disaster is simple. In fact, if you do these three things, you’ll enjoy great performance and minimal repair costs:

  • Purchase clean, reliable fuel
  • Change your fuel filter every 40,000 miles
  • Keep your fuel tank at least one-quarter full most of the time