Fuel pump not priming

Discussion in 'TR650' started by duibhceK, May 21, 2017.

  1. duibhceK Husqvarna
    AA Class

    Location:
    Chapel of the Well, Belgium
    Husqvarna Motorcycle:
    TR650 Terra
    Other Motorcycles:
    TRX850; WR450F; XT660Z Tenere
    I have finally gotten around to doing the valves on my wife's Terra. After having done mine when the engine was out to replace the bottom end, I thought I'd try with the engine still in the bike this time. I can tell you next tile I'll just drop the engine again. It is a royal PITA to get at everything with the engine still in. Especially with the rigid ABS lines blocking access to both the valve cover and the cam chain tensioner... at 70000km the intake valves were at 0.28mm so at the top end of recommended clearance. Exhaust valves were at 0.45mm, so slightly over the 0.43 max. Still, not too bad. So far so good.

    After putting everything together though an rather annoying issue occurred. When turning on the ignition I no longer hear the fuel pump prime. Strangely enough, the bike does start and seems to run ok, at least for the few seconds I tested it (exhausts weren't on yet). Anyone have any suggestions where I should start looking first?

    I already tried hooking up another fuel pump, just to make sure it wasn't the pump itself at fault.
    I also switched the fuel pump relay over with another one to exclude that as well. No change.
    I checked with the multi-meter on the fuel pump plug and compared to the one on my bike. On both bikes there's 12V between pin 2 (white/blue) and pins 3 (brown) and 4 (brown). But on my bike, when turning the ignition on there's also 12V between pin 1 (green) and pins 3 and 4 for a short period. I'm assuming that's what make the pump prime. On my wife's bike no current between these pins at any time.

    No warnings or errors on the dash.

    I think I reconnected all plugs properly and the fuses seem fine as well.

    Anyone have other things in mind I could check (or re-check)?
  2. duibhceK Husqvarna
    AA Class

    Location:
    Chapel of the Well, Belgium
    Husqvarna Motorcycle:
    TR650 Terra
    Other Motorcycles:
    TRX850; WR450F; XT660Z Tenere
    After a quick look at the workshop manual, it seems that pin 1 on the plug is used by the fuel reserve switch. Since my bike indeed was low on fuel, it makes sense that there's 12V on that pin but not on my wife's bike as her tank is about half full. So I guess that's not where the problem is located.

    Still trying to figure out what initiates the priming then. The ECU?
  3. WayneC Husqvarna
    AA Class

    Location:
    Sydney
    Husqvarna Motorcycle:
    none
    Other Motorcycles:
    F650GS Dakar
    The Fuel Pump Relay is operated by earth switching from the BMS-E on pin 6 (Brown/Yellow), the switched leg will be monitored by the BMS-E for fault code generation. Dont waste time with the single page electrical diagrams in the workshop manual, get the full 9 original multi page diagrams plus legend which are on Google Drive, they have far more detail and easier to read, see this thread by MatLax for the link to all the manuals for TR650
    nev.. likes this.
  4. duibhceK Husqvarna
    AA Class

    Location:
    Chapel of the Well, Belgium
    Husqvarna Motorcycle:
    TR650 Terra
    Other Motorcycles:
    TRX850; WR450F; XT660Z Tenere
    Thanks for the tip, Wayne. I'll take a look at those.
  5. Casey 250FC Husqvarna

    Husqvarna Motorcycle:
    250 FC
    Do you know where I can find the wiring schematics for a 2016 250 FC. My bike won't start, new battery, new plug and when hooked up to the computer at the dealer, it starts right up. Computer says something about a Fuel pump relay or ground????