Difference Between Return and Returnless Fuel Systems

Fuel systems are one of the most important operations in a vehicle. After all, they simply would not go anywhere without a fully-functioning fuel distribution and management. There are two main types of fuel systems, return-type and returnless-type. Do you know which type of fuel system your vehicle uses? If you are ever in need of fuel system service or repair, it is something that will certainly help your overall understanding.

It is important to understand how your system works, and what type of system you have so that you are better prepared in the case of a needed repair or service. Continue reading to learn more about fuel systems, including the difference between return and returnless-type fuel systems.

Indianapolis Fuel System Repair 317-475-1846
Indianapolis Auto Repair and Service 317-475-1846

How a Fuel System Works

A vehicle’s fuel system is in charge of storing, controlling, and supplying the engine’s combustion chamber with fuel. A fuel system comprises of a fuel tank, fuel pump, fuel lines, fuel filters, and fuel injectors. The fuel is stored in the fuel tank until the fuel pump draws it out. From there, the fuel travels down the fuel lines, through the fuel filter, and then to the engine’s combustion chamber by means of the fuel injectors.

In this process, the fuel is mixed with air, atomized, and ultimately vaporized. Atomization and fuel pray patterns from the injectors play a large role in completing the combustion operation. Spray patters vary depending on the spacing, angle and number of holes in the injector tip. Atomization occurs tanks to injection pressure, which is regulated depending on the type of fuel system you have.

Return-Type Fuel Systems

A return-type fuel system is one that is designed with a fuel pressure regulator that diverges the fuel pressure based on the power of vacuum suction from the engine’s intake system. The purpose of the pressure variant is to ensure that the amount of fuel pressure and flow remains equal and consistent when the fuel reaches the injectors.

Returnless Fuel Systems

A returnless-type fuel system is one that is designed to use the powertrain control module (PCM) to regulate fuel delivery. A fuel pressure sensor mounted to the supply rail of the fuel injectors allows the powertrain control module to keep an eye on the fuel pressure. If the fuel pressure and flow starts to decrease as a result of increased engine speed or load, the powertrain control module will make up for the drop by increasing the injector duration and/or operating speed of the fuel pump.

Signs of Fuel System Issues

Below is a list of the most common signs of fuel system malfunctions. If you notice any signs of fuel system trouble, it is strongly advised to take your vehicle to an ASE certified and licensed Indianapolis auto repair shop for emergency diagnostics.

Check Engine Light

Problematic Engine Starting

Slowed or Hesitated Acceleration

Intermittent Power Loss

Rough Engine Idling

Engine Smoke

Smelling Fuel

Indianapolis Fuel System Service and Repair

Factory Scheduled Maintenance Indianapolis IN

Call Northeast Auto Service at 317-475-1846 for fuel system service and repair in Indianapolis, Indiana. We are ASE licensed and certified car mechanics who provide a wide range of foreign and domestic auto repair services, and specialize in major engine and transmission work. We also offer free estimates, automotive repair coupons, assistance with towing, and more. Request a free estimate, anytime.

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