Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.

What is a "return-type fuel system" and "returnless fuel system"?

I am setting up a turbo-charger system for my Lancer Evo 6 and wondering if it has a "return-type fuel system" or a "returnless fuel system"? And fuel management system for the application.

Update:

And which system is better?

7 Answers

Relevance
  • 1 decade ago
    Favorite Answer

    You're probably familiar with "return-type" fuel injection systems, but have you worked on a "returnless" system?

    Returnless systems are found on many late model cars and trucks. The first ones appeared back in 1993 on certain Chrysler V6 and V8 truck engines. By 1998, all Chrysler cars and light trucks had them. In 1996, Toyota introduced its first returnless system, followed by General Motors and Ford in 1999. Honda went "returnless" in 2001, and today you'll find returnless fuel injection systems on almost all new vehicles.

    In the older return-type systems, the fuel pump delivers more fuel to the engine than it actually needs. The excess fuel is then routed back to the fuel tank through a pressure regulator and return line. But in a returnless system, there is no pressure regulator on the fuel supply rail and no return line back to the tank. The regulator is mounted in the fuel tank and is usually part of the fuel pump module.

    A returnless fuel injection system, by comparison, manages fuel pressure a little differently. Instead of using a spring-loaded vacuum diaphragm in the regulator to change fuel delivery when throttle opening and intake vacuum change, the regulator in a returnless system operates at a constant pressure. The older return-type systems need to vary fuel pressure to maintain the same pressure differential across the injectors when intake vacuum drops. When vacuum drops, the regulator increases pressure to compensate. But in a returnless system, this isn't necessary because the line pressure is always the same.

    So how does the system compensate for changes in engine load and vacuum? A returnless system uses the Powertrain Control Module (PCM) to regulate fuel delivery. A fuel pressure sensor mounted on the supply rail allows the PCM to monitor fuel pressure. When pressure in the supply rail drops as engine load or speed increase, the PCM compensates by increasing injector duration (on time) and/or the operating speed of the fuel pump.

    Some systems (Ford, for example), vary the fuel pump's output by changing the voltage supply to the fuel pump module. When more fuel is needed, pump speed is increased by increasing the pulse-width (on-time) of the pump's voltage signal (pulse-width modulation).

  • karle
    Lv 4
    4 years ago

    Returnless Fuel System

  • Anonymous
    5 years ago

    Fuel Return Line

  • 6 years ago

    This Site Might Help You.

    RE:

    What is a "return-type fuel system" and "returnless fuel system"?

    I am setting up a turbo-charger system for my Lancer Evo 6 and wondering if it has a "return-type fuel system" or a "returnless fuel system"? And fuel management system for the application.

    Source(s): quot return type fuel system quot quot returnless fuel system quot: https://bitly.im/cIYfx
  • How do you think about the answers? You can sign in to vote the answer.
  • Eric F
    Lv 6
    1 decade ago

    a return type fuel system has a line going from the fuel rail after the fuel regulator to dump excess gas back into the tank. the returnless simply keeps the excess gas in the line until it gets injected.

  • Anonymous
    5 years ago

    For the best answers, search on this site https://shorturl.im/avyKf

    You ought to be open to getting an education as you have no clue what you are talking about. This is the gist of the other answers.

  • 1 decade ago

    beats me ask dealer or dealer of parts

Still have questions? Get your answers by asking now.