Tag Archives: yamaha

Breaking Down Fuel Pump Terminology: EFI, E85, LPH, Small Parts, and More

July 14, 2022ATV, AUTO, DIRT BIKES & MOTORCYCLES, OUTBOARDatv, dirt bike, dual pump system, fuel filter, fuel pump, honda, motorcycle, polaris, square body pickup, yamahaQuantum Fuel Systems

Unpacking the Language of Fuel Pump Components

Navigating the world of fuel systems shouldn’t be difficult, especially when you’re simply trying to order quality parts for your machine. When it comes to fuel systems, there is quite a bit of fuel pump terminology, whether you’re talking about automotive, motorcycle, ATV, UTV/Side-By-Side, or marine vehicles.

We’ve put together a helpful list of standard terms and definitions that you’ll come across when diving into a DIY repair for your vehicle. From basic definitions and acronym explanations — being familiar with fuel pump terminology will get you on the right path and keep you informed.

QFS specializes in producing high-quality fuel system components for nearly every EFI-equipped engine on the market. We design our direct replacement parts in-house and will meet or exceed OEM quality. We offer replacement fuel pumps, kits, and components for nearly all makes and models backed by an industry-leading lifetime warranty. Visit our complete catalog to order now.

Fuel Pump Terminology Explained

Electronic Fuel Injection

Electronic Fuel Injection (EFI) is any fuel delivery system that is electronically controlled by an Engine Control Unit (ECU). The name describes its function quite accurately because EFI systems inject fuel directly into an internal combustion engine’s manifold or cylinder. EFI has become the dominant fuel delivery method due to its inherent performance, emissions, and efficiency advantages over antiquated carbureted systems. There are several forms of fuel injection, such as single-point fuel injection, multi-point fuel injection, sequential fuel injection, and direct injection. Yet, they all follow the same fuel injection principles.

Fuel Injector

A fuel injector is one of the most crucial components in your EFI system; its function is where we get the name. Your vehicle’s Engine Control Unity (ECU) electronically control your fuel injectors. A fuel injector is an electronically controlled valve that sprays a precise amount of atomized fuel into the engine’s combustion chamber to facilitate an optimal air-fuel mixture under all operating conditions. QFS is an authorized dealer of fuel injectors from industry leaders such as Bosch, Injector Dynamics, RC Engineering, and Siemens Deka. We offer direct OE replacement and high-performance solutions for automotive, Powersport, and marine applications.

ECU/ECM

The Engine Control Unit (ECU) or Engine Control Module (ECM) is your vehicle’s brain. It controls one or several electrical systems. Part of its duties is managing the EFI system, performing essential tasks like how long to hold the injectors open during each cycle to create the proper air-fuel ratio for any situation. It achieves this by monitoring data from several sensors and adapting accordingly.

OE Replacement

Original Equipment Replacement. All QFS products for powersports, from fuel pumps, O-rings, and more, match OE specifications and are guaranteed to be direct drop-in replacements.

OEM

Original Equipment Manufacturer.

Fuel Rail

A fuel rail is a high-pressure fuel line that delivers fuel to the fuel injector.

Fuel Pump Assembly

The fuel pump assembly often houses critical components such as the fuel pump, pressure regulator, fuel sending unit, and strainers or filters. QFS offers entire replacement assemblies for many makes and models.

Fuel Sending Unit

A fuel sending unit measures the amount of fuel available in your fuel tank and communicates that information to the fuel gauge. It does not send fuel as the name suggests and instead sends an electrical current from the fuel level sensor to the fuel gauge. If your vehicle cannot accurately register fuel levels, a fault with this component can be the cause.

Fuel Pump

Direct OE replacement fuel pumps are what Quantum Fuel Systems (QFS) specializes in, supporting nearly every corner of the automotive, Powersports, and marine market. The fuel pump delivers high-pressure liquid fuel to a carburetor or EFI system within the engine. QFS fuel pumps feature an industry-leading lifetime warranty and are designed to withstand a variety of ethanol-gasoline fuel blends.

Intank Fuel Pump

“Intank” or “in-tank” refers to the physical location of the fuel pump. An intank fuel pump is located inside the fuel tank and explicitly designed for that purpose. Intank fuel pumps typically achieve longer operational lifespans than alternative designs since they are submerged in liquid fuel, helping cool and lubricate the pump.

External/Inline Fuel Pump

External/Inline fuel pumps mount on the exterior and underneath a fuel tank while using gravity to feed fuel into the pump. An external/inline fuel pump is often far easier to service and replace due to its mounting location.

QFS PERFORMANCE 380LPH INLINE EXTERNAL E85 COMPATIBLE FUEL PUMP W/ INLET OUTLET, QFS-606FT

ADD TO CART

Small Parts

This is a term that comes up in conversation with gearheads, sales staff, and suppliers within the fuel-system industry. “Small parts” refers to any components that are not the actual fuel pump. This can include but is not limited to; O-rings, gaskets, strainers, filters, pressure regulators, and other parts associated with fuel pumps. QFS has all the small parts you need to get your vehicle running again.

Filters

Filters do the critical job of extracting harmful particulates from fuel to protect sensitive EFI components. QFS filters screen microscopic contaminants that collect in a fuel tank and ensure that your vehicle’s EFI system is running at its best. A car, motorcycle, ATV, UTV/Side-by-Side, or boat may employ one or more filters at various stages of the fuel system.

Strainers

Strainers perform the same function as filters and are typically the first line of defense against fuel system contaminants. Common contaminants such as sand, dirt, dust, and gasoline varnish are screened out by QFS strainers, which feature multi-layer strainer media to filter even the smallest particulates. In addition, QFS strainers boast an expanded surface area. This offers improved filtration abilities and extending the life of your fuel system components.

Pressure Regulator

The pressure regulator helps maintain proper PSI within your EFI system. This allows your fuel injectors to function correctly and air-fuel calculations to be as accurate as possible.

Dual Pump System

Any fuel system that relies on two fuel pumps is a Dual Pump System. In these systems, a low-pressure fuel pump transfers fuel from the fuel tank to the engine, then a high-pressure fuel pump takes over and delivers fuel to the EFI system. These systems are commonly used in marine applications where the fuel tank is not near the engine.

E85 Fuel (Flex Fuel)

E85 is an ethanol-gasoline blend of fuel that can contain anywhere from 51% to 83% ethanol, depending on the season and location. Flex Fuel or E85, is explicitly formulated for Flexible Fuel Vehicles (FFVs), meaning that the internal combustion engine is designed to support high-volume ethanol fuel blends. While cheaper than gasoline, it has less energy density and often results in reduced fuel economy. This fuel cannot be used in motorcycles and Powersport vehicles.

Tank

The fuel tank. Every ICE-powered machine has one (or more).

Performance

Performance fuel system equipment means that you need components with superior flow rates than what OE equipment can provide. When building high-horsepower engines, this type of equipment is an absolute necessity to meet the increased performance demands.

Polytetrafluoroethylene (PTFE)

Polytetrafluoroethylene (PTFE) is a durable synthetic fluoropolymer used in all QFS corrugated flex hose lines. This robust plastic is hydrophobic and resistant to the harsh chemicals in today’s fuels, including E85. The corrugated design also prevents kinking and improves fitment in all uses.

AN Fittings

AN is a U.S. military-derived specification standard dating back to World War II, developed as a common standard between the Army and Navy branches. QFS is an authorized dealer of high-quality AN fittings from Phenix Industries. Phenix Industries provides customers with the finest aftermarket high-performance fuel and brake system plumbing components available.

PSI/kPa

Pounds per Square Inch/Kilopascal are two standard measurement units when describing fuel pressure regulator specifications. PSI is an Imperial measurement, and kPa is metric. Be sure to reference what measurement unit your model-specific service manual cites.

LPH/GPH

Liters Per Hour/Gallons Per Hour are two frequently cited units of measurement. They are used to reference the amount of fuel a pump can supply over time.

Pulse Width Modulation (PWM)

Pulse Width Modulation allows an ECU to control EFI fuel pressure by rapidly turning a fuel pump on and off. If more pressure is needed, the length of time the fuel pump is activated extends. Conversely, if less fuel pressure is required, the time the fuel pump is turned on is reduced. This can happen in milliseconds. It extends the useful life of a fuel pump by allowing it to work less, operate at a lower temperature, and introduce less heat to the stored fuel. All QFS fuel pumps are PWM-ready.

Quantum Fuel Systems is open Monday through Friday, 8:00 a.m. to 5:00 p.m. PT. Any of our trained and qualified staff members are available to assist customers over the phone. Be sure to reach out to our support staff with any technical questions, and we’ll get back to you as soon as possible.

How to Diagnose a Bad ATV, Motorcycle, UTV/Side-by-Side Fuel Pump

February 2, 2022ATV, AUTO, DIRT BIKES & MOTORCYCLES, OUTBOARDatv, can-am, dirt bike, fuel pump, honda, motorcycle, polaris, yamahaQuantum Fuel Systems

how to quickly identify a failing fuel pump QFS

How to Diagnose a Bad ATV, Motorcycle, UTV/Side-by-Side Fuel Pump

Understanding the symptoms and how to diagnose a bad fuel pump on an ATV, motorcycle, or UTV/SxS is handy knowledge for any enthusiast and precisely what we’ll be discussing below. When a fuel pump fails to operate within its designed specifications, your EFI-powered vehicle can suffer in a few ways. Expect lowered performance, causing it to run poorly, or failing to start at all.

A properly functioning fuel pump is one of the many crucial components in your ATV, motorcycle, or UTV/Side-by-Side (SxS).

Quantum Fuel Systems specializes in high-quality direct OEM replacement fuel system and engine management components. All QFS products are backed by an industry-leading lifetime warranty. Every product in our extensive Powersports product line is designed to match the technical specifications of your vehicle.

We know how important it is for our customers to get back on the road or trail. Your orders are processed the same business day, and we offer free 2-day shipping in the United States with any purchase above $60. QFS has you covered with complete replacement kits, individual parts, specialty tools, and more.

Whether we’re talking about two or four-wheeled vehicles, testing a bad fuel pump, or issues related to your fuel system are similar. It doesn’t matter if you drive an Arctic Cat, Can-Am, or Polaris, ride a Harley-Davidson, Honda, or Husqvarna. Fuel pumps can fail anytime, anywhere.

Get the Gold standard in OEM Quality Replacement Parts QFS once you diagnose a bad fuel pump

What does matter is that you’re referencing your vehicle-specific service manual to confirm any necessary technical specifications, as those figures can change depending on the vehicle year, make, and model.

Luckily, troubleshooting a bad fuel pump follows the same general principles, and we’ll be covering a few basic and advanced methods.

QFS does not intend this article to be a strict guide. As always, we recommend that only those confident in their mechanical abilities perform maintenance, repairs, and diagnosis on their vehicles.

If you do not feel comfortable performing this work, please consult an authorized and licensed service technician.

SECTIONS

TOOLS YOU’LL NEED

SYMPTOMS OF A BAD FUEL PUMP

DIAGNOSING A BAD FUEL PUMP

FUEL PUMP WON’T PRIME

CHECK THE FUSES & RELAY

CONFIRMING YOUR FUEL PUMP HAS POWER

PRESSURE TESTING A FUEL PUMP

ORDER

Tools You’ll Need To Diagnose Fuel Pump Problems

Eye protection
Nitrile gloves
Hand tools (socket and screwdriver set)
Pliers
Multimeter or voltage meter
Pressure testing gauge
Contact cleaner
Rags

Symptoms of A Bad Fuel Pump

Let’s dive into it with how to diagnose a bad fuel pump and review some tell-tale symptoms of an underperforming or failed fuel pump.

Not Starting/Won’t Idle

Not starting when all systems appeared to be in regular working order is a good indicator that fuel is not making it through the fuel system. If the engine does start but fails to maintain idle, that is another sign that the pump is on its way out.

Whining

All fuel pumps produce a low audible hum when operating. When they reach the end of their lifespan, you may notice a loud whining sound, pointing to a fuel pump motor stressing itself to function.

In-Tank Fuel Pump Assembly for 2016-2023 Polaris RZR Turbo

ADD TO CART

Surging

Surging occurs when traveling at a constant speed and feels as if your ATV, motorcycle or UTV briefly accelerates with no input from the user. Typically, excessive pressure buildup can momentarily deliver excess fuel. In this case, we strongly recommend replacing the pump and filters immediately.

Power Loss Under Load/Cut outs

Does your bike, quad, or SxS accelerate normally only to begin losing power as the rpm climb or at higher rpm? That is often a signal of a fuel pump that cannot deliver the correct amount of fuel pressure to meet performance demands. Alternatively, you may experience power cut-outs at random, demonstrating a fuel pump operating sporadically.

Diagnosing a Failing Fuel Pump

Pinning-down fuel issues can be complex, as fuel systems and electrical systems are interdependent. Problems with one system can cause the other to malfunction. Our goal here is to isolate variables and help you determine the root cause of your issues.

Before you turn a single wrench, start with the basics and confirm a few things:

Is there fuel in the tank, and does your fuel gauge (if applicable) register accurately?
Is your battery adequately charged, and does your electrical system appear to be fully operational?
Is the kill switch in the “run” position?
Is your bike, SxS, or quad in neutral?

If you’ve answered yes to all those questions and you’re still experiencing issues, then it’s time to start investigating.

Fuel Pump Won’t Prime

Fuel pumps can fail with or without warning. We go to fire up our ATV, motorcycle, or UTV; the engine cranks, and it simply won’t start. Our first step is to observe if the fuel pump is operational and “priming.”

Priming means that the fuel pump engages for a short time, pressurizing the fuel lines and providing adequate fuel flow for the injectors.

To test this, cycle your key to the “on” position and listen intently for an audible hum coming from the fuel tank. The hum should only last a few seconds.

If you’ve repeated this multiple times and don’t hear a mechanical whirring, chances are the fuel pump has failed or is not being supplied electricity.

If you are performing this test on a dirt bike (Motocross or Enduro) that doesn’t have a keyed ignition, press the starter button and quickly release, which will trigger the fuel pump and allow you to determine if the fuel pump is operational.

Check the Fuel System Fuses & Relays

Fuses and relays act as bridges for electrical current. If they fail, the current can’t reach its proper destination and provide power. Consult your service manual to access your fuse box and relays, and then remove them to inspect them for any damage visually.

sign up for a coupon for your fuel pump replacement QFS

A healthy fuse will have its metal “bridge” connected, and a functional relay will “click” when power is delivered. You can also use a multimeter to check the resistance of a relay or fuse, which is more accurate.

Confirming Your Fuel Pump Has Power

If your fuel pump is not priming, you must determine if this is an electrical problem or a fuel pump failure. To do that, you will need to gain access to your vehicle’s fuel pump assembly. Consult your model-specific service manual for instructions to perform this safely.

Once you have clear access to the fuel pump assembly, you will want to test if power is coming down to the fuel pump itself with a multimeter or voltage meter.

Shop Polaris Sportsman Fuel Pump Assembly QFS

Disconnect the wiring from the fuel pump assembly. Again, you will need to consult your service manual and wiring diagram to determine which terminal connections to measure.

Once you’ve done that, confirm that adequate power is available by cycling the key to the “on” position and measuring the voltage — it should rise to the cited technical specification in your service manual, then fall to zero after a few seconds. If you don’t have power or insufficient voltage, you know that the issue is not related to your fuel system.

If all is in order with the wiring harness, perform a continuity test with your multimeter on the fuel pump itself. Locate the positive and negative leads going to the fuel pump and check if an electrical connection is capable.

If it isn’t, rest assured that the fuel pump motor is dead.

Pressure Testing a Fuel Pump

Pressure testing is crucial when faced with lean and rich conditions, power loss, or surging, as irregular pressure in your fuel system can cause these issues. This test requires one of the few specialized tools mentioned here since it will need a gauge with model-specific connections to be installed between the vehicle’s fuel pump and fuel lines.

Once you’ve determined your vehicle’s fuel pressure specifications and installed the pressure tester, cycle the key to the “on” position. Pressure must raise and hold at the required specification.

If that checks out, start the engine and increase the rpm gradually. Once again, pressure should not deviate outside the recommended range.

If pressure is excessively high, your pressure regulator has failed, and we offer replacement options. Conversely, clogged fuel filters can lower fuel pressure and create flow issues.

Inspect all relevant filters thoroughly, although we recommend replacing them during this type of service. To accurately diagnose a bad fuel pump, all other fuel system components must be thoroughly checked.

We Are Standing By For Your Order

You can order from Quantum Fuel Systems, Monday through Friday, 8:00 a.m. to 5:00 p.m. PT, over the phone or browse our extensive catalog. Be sure to contact use our support page for any detailed technical questions, and we’ll get back to you as soon as possible.