TE310: Unrideable at low fuel level (EFI/fuel pickup)

Discussion in 'EFI/carb' started by Alexander, Sep 30, 2019.

  1. Alexander Husqvarna
    AA Class

    Husqvarna Motorcycle:
    TE310'11
    Hi!

    I think this topic should be in this area of Forum, as it is EFI/Fuel pump related.

    TE310 `11, runs great until the fuel level drops and the "low fuel" light is on. Then the bike starts but any twist of the throttle stalls it. Won't rev. Known issue, I guess. Not enough fuel pressure.

    Other than that, everything is perfect/tuned. Pump is OK, new fuel filter, ECU tuned with iBeat (no 12-hole/TXC mods though). The fuel bypass (left-right side hose under the tank) is OK. I ride technical trails in Enduro-parks, so the engine pulls in tough conditions.

    Anyone considered some mods to allow it to use MOST of the fuel? Like drilling the plastic FI pump holder, etc...

    I might be doing rallys on the bike so it is really important.

    WBR,
    Alex
  2. Alexander Husqvarna
    AA Class

    Husqvarna Motorcycle:
    TE310'11
    OK, it is clear and visible what is happening. I'll try to explain on a real-world example.

    - Fill your bathtub with 10-20cm of water and open the tap. The water drops into the bathtub and creates a million of bubbles. Because it drops through the air.
    - Close the tap, put the shower head into the bath, under the water. Open the tap. Water flows from the shower head but there is no bubbles. (Ok, if you live in the US, the shower head is fixed ;) ).

    EXACTLY THE SAME IS VISIBLE in the tank. If the gas level is lower than the top of "black plastic pump casing", the gas from return pipe rushes into this casing through the air and creates bubbles. Casing makes it worse as catches the bubbles. These are immediately sucked by the fuel pump. Air in the fuel line -> Loss of fuel pressure -> Stalling issues.

    So the "casing" of the pump is working exactly NOT as designed. Maybe the issue can be fixed by routing the return pipe far away from the pump. Or making it reach the bottom of the "casing" (inside it).

    The problem is programmed from the factory...