KTM 990 fuel pump replaced, now won't start

Discussion in 'Crazy-Awesome almost Dakar racers (950/990cc)' started by Jaunt, Jun 8, 2019.

  1. Jaunt

    Jaunt Adventurer

    Joined:
    Mar 29, 2011
    Oddometer:
    53
    Location:
    Central Iowa
    I'm on the road and hitting the NMBDR tomorrow morning. We traveled about 650 miles to SE Colorado today and as I was pulling in to Lamar, CO, my bike was dying under throttle. It would cut out at like 1/8 throttle. One of our crew had a spare fuel pump and filters, so I swapped everything out and now the bike will not fire.

    I can hear the pump spinning and fuel is getting past the disconnect.

    Any ideas??

    Jaunt
    #1
  2. soupbone

    soupbone Been here awhile Supporter

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    Nov 24, 2009
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    397
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    rio verde foothills
    Pull the pump again. The white cap is possibly loose. It will flow fuel but not build the pressure needed to run. There is a thread about this. Use a tyrap to make sure it stays connected in the tank
    #2
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  3. Jaunt

    Jaunt Adventurer

    Joined:
    Mar 29, 2011
    Oddometer:
    53
    Location:
    Central Iowa
    I pulled the pump and one of the tabs was loose on the white cap. Got that fixed and tied it in place, still no go.

    Pulled my buddy's tank, hooked it up to my bike and it fired right up.

    I'm at a loss. What am I overlooking?
    #3
  4. DirtyADV

    DirtyADV Long timer

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    If it runs with your buddies tank the fault is narrowed down to the pump.

    Sure you have all the O-rings in place? Maybe one of them is damaged? Not letting it build up required pressure cause you said it does pump fuel.

    /Johan
    #4
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  5. tomdubz

    tomdubz getting there Supporter

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    Is the brass tube solidly in place with good o rings?

    Or, what are the chances that the pump your buddy had is somehow compromised? How long has it been rattling around in his kit?
    #5
  6. FakeName

    FakeName Wile E Coyote SuperGenius

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    Did you try your tank on your buddy's bike?
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  7. Salzig

    Salzig Long timer

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    Check also the pins in the pump plug. They can slip out.
    #7
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  8. Mud Bucket

    Mud Bucket Been here awhile

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    Aug 9, 2007
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    North Vancouver,B.C, Can
    Not sure if you checked this but during a filter change I mistakenly replaced an O'ring to the pressure regulator on the top of the pump. My bad, but what I learned was to check the pressure of the line. The pump would cycle for a couple of seconds when turning on the key then stop,"normal" but the bike would not fire up. I plugged in everything and felt the fuel line on the motor side of the discontent. With the bolts loose to the tank, there is enough room to reach in and squeeze the line hard with your fingers. If you can easily squeeze and pinch the line after the pump cycles on start up you have loss of pressure. If its hard and stays hard the pressure is good and its most likely another issue.

    Not sure if this helps but good luck
    #8
  9. Jaunt

    Jaunt Adventurer

    Joined:
    Mar 29, 2011
    Oddometer:
    53
    Location:
    Central Iowa
    I appreciate everyone's help on this. I was able to get it to work and just got home today after riding a good portion of the NMBDR.

    I realized that the fuel was leaking at the brass pipe because the aftermarket fuel pump had a slightly different configuration from OEM and I did not get it fully seated. I ended up filing away some of the base "tabs" on the replacement fuel pump and then racked the steel cage slightly to get the electrical connectors to line up. That change allowed everything to seat properly and get a good seal. The replacement pump had to rotate clockwise about 1/4" to work. I could have saved myself some time and frustration by measuring the seated depth of the OEM pump to make sure I knew how far the replacement pump needed to be inserted in the base. I also just took it for granted that both pumps were oriented the same.

    I was really surprised by this failure. Along with earlier filter replacement, I had taken the time to replace all the fuel filters and also install the guglatech neck filters about 7k miles ago. I didn't expect to see the fuel pump fail with about 24,000 miles on the clock. The fuel filters looked good but I replaced them with new during the pump swap. I'm going to add another replacement pump to my tool kit and carry filters! If you have the parts....and they fit...this doesn't take long to fix in the field.

    Again, thanks to all of you for your advice! I was grateful to be able to continue my adventure! (New Mexico was outstanding)

    Attached Files:

    #9
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  10. hennessyktm

    hennessyktm Still here...

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    Glad you got it sorted. Thanks for the summary/explanation on how you solved it.
    #10
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