Common Fuel System Issues with Performance Vehicles

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Common Fuel System Issues with Performance Vehicles

Performance is feeling the thrill of speed and acceleration, but without a fuel delivery system that can meet your expectations, the ride may fall a little flat. Many different problems can manifest themselves to diminish performance of your vehicle’s fuel system. From the fuel pump, the lines, and through the fuel injectors, each component can create fuel system issues and hinder the response of your performance vehicle.

Common Symptoms of Fuel System Issues

There are a few key indicators that your fuel system is having some kind of issue. While most can seem similar, they can show themselves in many ways.

These are the more common symptoms you’ll identify:

·         A hesitation or stalling engine response

·         A No Start or hard starting condition

·         Varying performance, throttle response / acceleration at differing speeds

·         An engine misfire or sputtering condition (could also be surging)

·         Losing power and response when under a load

·         Decreasing gas mileage from one tank of fuel to the next

Any of these symptoms can be an indicator that your performance vehicle’s fuel system has an issue. The next thing to do after you detect a problem is to find out what component is the culprit.

What Fuel System Components Can Have Problems?

Your performance vehicle’s fuel system has a handful of components. Each must perform correctly to ensure proper fuel flow from beginning to end.

These are the main fuel system components in your system:

·         Fuel pump with pre-screen sock / filter

·         Fuel filter (typically in-line with the pressure fuel line)

·         Fuel lines (can be both pressure and return lines)

·         Fuel injectors + fuel rails

·         The fuel itself (gasoline, diesel, or other)

Fuel Pump

The fuel pump is the heart of the fuel system. Most high-pressure fuel pumps have a pre-screen filter (also commonly called a sock) attached where the fuel enters the pump body. This can become dirty over time, and cause some of the hesitation and fuel starvation issues.

The pump itself has a handful of failure modes that can lead to performance issues. How well they work can be a tell-tale sign that they are having an issue. You may hear the pump have a loud electrical clicking sound or excessive whining when it begins to fail.

If it struggles to build sufficient pressure at start-up, the vehicle may have trouble starting or is harder to start than it has been in the past. Any failing fuel pump can also trigger misfires, sputtering, or cause a losing power condition under a load. You won’t have the necessary fuel to maintain performance, and that is going to cause the system performance to suffer.

Fuel Filter

The fuel filter removes particulates from the fuel before it travels to the engine and fuel injectors. The filter may also act as a pressure regulator for the fuel system. Your performance vehicle may start to decrease power or throttle response under load. This indicates the filter is nearly full of contaminants and can’t flow enough fuel to the engine.

Most auto manufacturers have a replacement frequency defined for preventative maintenance. However, if find that your vehicle has lost performance it may be time to replace the fuel filter. Most are located under the vehicle in-line with the fuel lines near the fuel tank and just require basic hand tools to replace.

Pressure and Return Fuel Lines

Your fuel lines move the fuel from the fuel tank, to the fuel filter, and then on to the fuel injectors and engine. Most are rated for the type of fuel specified for use (such as gasoline or diesel), and they will typically last the lifetime of the vehicle with proper maintenance.

The main issue with fuel lines is clogging because of debris. If the vehicle is used regularly, you shouldn’t expect that debris will buildup in the lines. The biggest opportunity for buildup is a performance vehicle that sits for extended periods of time without proper maintenance or preparation.

A secondary issue with fuel lines is using a different type of fuel than specified by the manufacturer. Fuels such as E85 or methanol can degrade and damage standard fuel lines, which can cause leaks. If you plan to use a different fuel type than the approved type of the manufacturer, you may want to replace the lines with new material rated for the new fuel type.

Fuel Injectors + Fuel Rails

The injectors and fuel rails spray the fuel into the intake manifold, cylinder heads, or directly in the engine cylinders. They are susceptible to clogging and damage as the other mentioned components are, and they are also rated for a specific fuel type.

As mentioned with the fuel lines, changing to E85, methanol, or another fuel with a higher ethanol or alcohol content can degrade the seals on the injectors and cause a leak. A damaged injector can cause a hesitation with the engine response and performance and can negatively affect your vehicle’s gas mileage.

In many cases the injectors can be kept clean with a fuel treatment solution added to the fuel at the time of a fill up. If the injector is degraded or damaged beyond repair, it will need to be replaced.

The Fuel You Use

If your performance vehicle suddenly has an issue, it may not be the result of a defective or degraded component in the system. It may be the fault of the fuel itself. Gasoline and diesel does have a time period where it keeps stays fresh, but over time it will degrade without preparation for storage.

If you recently filled your fuel tank and suddenly have a performance problem, the fuel may be the wrong type (adding diesel instead of gasoline) or the fuel could be degraded sufficiently to cause a performance problem. If you need to replace the fuel, it may require pumping the fuel tank dry or removing it completely.

You may also need to replace other components like the fuel filter to ensure all of the incorrect fuel has been removed from the system.


QFS Is Here To Help

Keeping your fuel system in excellent shape is easy with proper maintenance. It can be as simple as adding a fuel system cleaner and treatment every few tanks of fuel. You may also want to avoid driving or storing your vehicle with a low amount of fuel in the tank.

The fuel adds lubrication and cooling to the pump to prevent degradation and overheating. If you need to replace any fuel components, you can order a better designed replacement pump, complete assembly, or just the missing pieces you need for an upgrade 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 us via our support page for any detailed technical questions, and we’ll get back to you as soon as possible. For over 15 years, Quantum Fuel Systems has been manufacturing and distributing fuel system components for OEM and performance applications. We strive to manufacture fuel systems that center around longevity, accurate flow data, and hassle-free direct fitment.

Also be sure to snap a few pictures during and after youtr ride, or if you are a video creator, send us a link to your video on our ‘Submit Your Ride’ page. We love to see what you’re working on, riding, and hear about your experience!