How Does A Diesel Lift Pump Work?

A low-pressure fuel supply pump known as a fuel lift pump transfers fuel from the tank to the injection pump. The lift pump, which is most commonly used in vehicles with diesel engines, essentially produces pressure or suction in the gas tank, causing gasoline to rise to the injection system and engine.

The high-pressure injection pump or unit injectors, which often boost pressure to thousands of psi, pressurize the fuel pressure from the lift pump.

How do you test a diesel lift pump?

, immediately switch the ignition key to the start function to prevent the engine from starting, and then let go of the key, leaving it in the run position (the lift pump should run 25 seconds). If you don’t hear the lift pump, check for 12 volts going into it; if it doesn’t run with 12 volts, it needs to be replaced. Replace the fuel filter if you hear it running and it doesn’t make at least 5 PSI at idle.

Why do diesels need a lift pump?

A lift pump’s job is to deliver low-pressure gasoline (from the tank) to the engine’s injection pump. Most lift pumps, whether aftermarket or OEM, deliver 8 to 15 psi of supply pressure (aside from the 7.3L, 6.0L and 6.7L Power Stroke engines, which call for 45-to-65 psi). The injection pump or injectors pressurize the fuel that makes its way into the cylinder between 15,000 and 30,000 psi (depending on the engine and injection system the engine has).

The injection pump would have to pull fuel all the way from the fuel tank if it wasn’t supplied with low-pressure fuel via the lift pump (which is the case in Duramax applications). Its life duration is considerably shortened if there is insufficient fuel going into the low-pressure side of the injection pump. Continued deprivation of fuel will eventually harm the injection pump and possibly the injectors.

What are the benefits of a lift pump?

Lift pumps have numerous advantages. Lift pumps are an important aspect of truck customisation, particularly if the goal is to increase power. They’re not as flashy as a supercharger, but they’re just as important. They increase fuel volume while simultaneously improving filtration, allowing for higher-quality gasoline to pass through the system.

Do all diesels have a lift pump?

Almost every diesel enthusiast has heard the term “lift pump” at some point. However, there are still some unanswered issues about the topic, such as what exactly is a lift pump and what kind of lift pump you require.

Simply described, a lift pump is a supply pump that transports fuel from the tank to the injection system of the engine. From antique mechanical injection systems to Ford’s HEUI system to current common-rail rigs, virtually every diesel has a lift pump of some type. Even engines like GM’s Duramax get fuel from the tank using a factory lift pump incorporated into the engine’s high-pressure CP3 pump.

So, if your engine already has a lift pump, why would you acquire an aftermarket lift pump? When it comes to increasing the power of a diesel engine beyond the factory specifications, one of the first changes that is made is to increase the amount of fuel injected. This can be done either mechanically (if the truck is computer-equipped) or by programming (if the truck is computer-equipped). The factory lift pumps are always one of the first sections of the system to fail when the engine’s fuel demand is pushed up to overdrive.

When the supply fuel pressure lowers, the injection pressure in the engine drops, and the engine’s horsepower drops as well. Running pressure that is too low in some circumstances (such as VP44 pumps found on 1998.5-2002 Dodges) might actually injure the injection pump and cause it to fail. When an engine is upgraded for increased power and performance, it’s a good idea to upgrade the lift pump as well.

The issue is that there are a number of lift pumps on the market. Low-pressure fuel pumps for gasoline systems are an appealing alternative with prices around $100, but they nearly invariably fail in a diesel application. Some pumps have lasted for years, while others have only lasted a few weeks. Some will fail completely, while others will simply begin to leak. An inexpensive lift pump intended as a fuel pump for a gasoline application, on the other hand, will almost always fail.

There are a plethora of diesel-specific alternatives on the market. Carter, PPE, and Aeromotive are just a few of the companies that manufacture diesel-specific pumps. Pump and filter combos are also available, which provide greater filtration, fuel-air separation, and higher-flowing filters that match the performance pump’s capabilities. These filter and pump configurations are by far the most prevalent option in the diesel sector, with manufacturers such as Airdog, FASS, Fuelab, and BD Diesel producing kits that are widespread on most diesel trucks.

Carter P4601HP

For the do-it-yourself set, Carter offers one of the most popular lift pumps. The Carter P4601HP pump has a flow rate of about 100 gph at 18 psi and doesn’t need an external regulator. These pumps are long-lasting, quiet, and suitable for low- to medium-horsepower vehicles.

Walbro 392

Many older 7.3L Ford diesels don’t require a lot of flow, but they do require pressure. Walbro GSL392 fuel pumps can be used to push enough of #2 diesel to the engine in these high-pressure applications. The Walbros, like the Carter, are quiet, long-lasting, and can be used with an external regulator for low-pressure applications. They have a flow rate of 68 gph at 60 psi.

Aeromotive A1000, Eliminator Series

Aeromotive fuel pumps, the granddaddy of homebuilt fuel systems, have been employed in high-horsepower applications for many years. The size of the feed and return lines on the Aeromotive pumps is critical, as small lines put too much strain on the motors, causing them to burn out. The Aeromotive pumps are a little louder than the Carter or Walbro pumps, but for the volume of fuel they can flow, they’re actually rather quiet. The Aeromotive A1000 pump has a flow rate of 145 gph and a pressure range of 20 to 80 psi, while the Eliminator pump has a flow rate of 250 gph and is well suited to competitive engines.


Airdog, one of the first fuel-air separator manufacturers, offers a variety of complete kits for Ford, Dodge, and GM diesel engines, including lines, filters, and pumps. From the self-regulating 100-gph Raptor series to the large 200-gph AirDog II pumps, the AirDog series comes in a variety of sizes and flow parameters. They’ve also released a new 4G model with a low-amperage engine and an intermediary shaft that prevents leaks by separating the air from the fuel. If you need a complete fuel system, AirDog is one of the companies that can provide it.

BD Diesel

While BD Diesel has been making lift pumps for a long time, they have just added a filter and a water separator to their product range, making it a complete kit. The Flow-Max Series of lift pumps uses filters available at local hardware shops, and their pump is an ultra-quiet model that is up to 16 decibels lower than the competitors. The lift pumps from BD have a flow rate of 150 gph at 15 psi.


FASS, another manufacturer with a long history in the diesel lift pump industry, offers everything from factory replacement lift pumps to ultra-high-flow units capable of 220 gph at 45 psi. FASS also manufactures pumps for Class 8 semis, making its lift pump line one of the most diversified on the market. The filters in FASS applications are intended to match the pump’s flow rating, and FASS units come in both low-pressure and high-pressure versions. Twin 220-gph pumps can sustain horsepower in the 1,500-2,000 hp range for demanding applications.


Fuelab, which has a long history in the gasoline racing scene, has just released the Velocity 100 and 200 series for most modern diesel trucks. The Fuelab series features a single water separator/filter and a high-performance low-amp motor. The Fuelab series’ filters may be cleaned or replaced, and the system comes with a two-year warranty. For Ford, Dodge, and GM applications, Fuelab offers complete kits in either the 100 or 200 gph series.


There are numerous of lift pump alternatives available, whether you want to do it yourself or buy a whole kit. Most 100- and 150-gph lift pumps will handle horsepower levels between 500 and 700 rwhp, whereas anything above 700 rwhp will require a bigger 200 or 250-gph pump, or two smaller pumps. Remember that a loss of pressure means a loss of dependability and power, which we all know diesel owners don’t want!

What is a lift pump Cummins?

When you start pushing your Cummins diesel vehicle beyond its original power limits, an aftermarket Fuel Lift Pump is often required to keep the fuel flow consistent. Most Dodge Cummins vehicles have diesel injection pumps that can deliver up to 30,000 psi to the injectors.

What is the difference between a fuel pump and lift pump?

In conjunction with a fuel injection system, modern gasoline pumps enable automobiles to travel at faster speeds while also improving fuel economy. Lift pumps contribute to this system by providing suction and controlling air flow to help raise the level of gasoline in the engine block. In an automobile’s fuel management system, these two distinct systems provide complementary roles, which is critical in contemporary high-performance automobiles.

How long does a lift pump last?

The unsung hero of your automobile is the gas pump. It transports gas from the gas tank to the engine, allowing your car, truck, or SUV to start and run. The fuel pump in your car should last at least 100,000 kilometers. If it doesn’t, or if you’ve passed that distance mark, you might see one of the seven indicators below. Bring your car to Primary Care Auto Repair in Warwick, RI if this is the case.

How is the fuel moved by the fuel lift pump?

The camshaft or a dedicated shaft driven by the crankshaft drives a mechanical fuel pump. When the lever pulls the diaphragm down, it creates suction, which draws fuel into the pump through a one-way valve along the fuel line.