KTM 990 Fuel Injection : Questions

Discussion in 'Dakar champion (950/990)' started by Commiehunter, Feb 12, 2020.

  1. Commiehunter

    Commiehunter Been here awhile

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    All,

    I'm diagnosing a KTM 990 that won't run. It cranks (I jumped the aux starter relay to bypass the starter interlock in the starting circuit), and it has spark.

    The fuel pump is providing fuel at a reasonable pressure. I haven't grabbed a dial to measure it exactly.

    The injectors flow fluid (cleaner) when I test them off the bike. However, when they're plugged in, they don't flow when I crank the bike, even if I'm supplying external cleaner fluid and pressure, to isolate from the fuel pump. Why don't they open when connected to the bike? I put a volt meter on the injector plugs and I thought I got 12 volts when the key is on but the bike is NOT cranking. It seems to go to about 7-9v when I'm cranking.

    Can you educate me on what the voltages should be, and when? How does the bike decide when to let the injectors run and when to close them? Why are mine staying closed?
    #1
  2. Commiehunter

    Commiehunter Been here awhile

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    Also looks like no have blink code 33, rear injector valve malfunction. Not sure even what that relates to. Is that a secondary air issue or the fuel injection itself?
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  3. ElwoodBlues

    ElwoodBlues Been here awhile

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    Maybe swop the rear with the front injector so you will know if the injector is really faulty.
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  4. Commiehunter

    Commiehunter Been here awhile

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    That's a good idea. At the moment they're both out and shuffled so I couldn't tell you which was the original rear.

    I did want to confirm that error is talking about the injectors, and not some other component. Also, it's possible that error came up because I was turning the ignition on with the injectors out, so I'll need to get them both plugged in and give it a few on/off to see it that persists.
    #4
  5. Commiehunter

    Commiehunter Been here awhile

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    Alright, I'm dumb. Code 33 was because I turned the bike on without the injectors connected.

    Ok so here are the codes now.
    7: sensor for 2nd throttle valve
    13: air temperature sensor
    54: secondary air valve

    All of these the manual lists "continue to run". I need to replace one of the injector o rings now, but once I get that I will attempt to verify my test on the injectors with them out and hooked up to full fuel pressure.
    #5
  6. gearheadE30

    gearheadE30 @LC8Adventures Supporter

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    sounds like maybe a bad ground somewhere? If the sensor and injector returns are tied together and a wire is broken or has high resistance, you'll have all kinds of odd symptoms.
    #6
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  7. chevtech

    chevtech Long timer

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    What all happened from the very start including whatever you have done....
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  8. Commiehunter

    Commiehunter Been here awhile

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    I bought a non running bike.
    I checked valve clearance.
    I checked all wires in the throttle body loom.
    I bought new battery.
    Specifically checked all wiring in the starting circuit. Checked function of start relay and aux start relay.
    Determined I had a bad starter interlock.
    Jumped aux starter relay.
    Bike cranks, dash functions.
    I checked spark with new spark plugs.
    Cleaned fuel pump.
    Checked fuel pump flow (by hand/eye, haven't measured pressure yet).
    Fresh ethanol free fuel.
    Still cranks, no start.
    Remove fuel injectors.
    Sprayed with cleaner, opened using spare batt to confirm they open and flow
    Reconnected fuel injectors to wiring.
    Ran spare hose with fuel and air pressure behind it.
    Cranked bike, no fuel from injectors.


    So my question was, why the bike didn't spray fuel from the injectors when they were plugged in.
    #8
  9. chevtech

    chevtech Long timer

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    What year 990? What key did you use? Do you have an anti-theft light on the dash? Looks like a little lock...
    #9
  10. chevtech

    chevtech Long timer

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    Does it crank with the key, or just you jumping it?
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  11. Commiehunter

    Commiehunter Been here awhile

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    It's a 2007. It doesn't have an immobilizer as far as I know. I don't see a lock icon on the dash.

    It cranks with the key on and using the button on the handlebar.

    The relay I jumped is the aux starter relay, not the main starter relay. The aux starter relay uses the interlock as ground. The interlock isn't letting the bike start, even in neutral with the kickstand up. Removing the interlock from the starter circuit, bike cranks with key and button.
    #11
  12. bomose

    bomose Long timer

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    If the cranking volts drop to 7-9, it could be a bad battery. My ZRX would turn over rapidly, but not start with the battery doing that.
    #12
  13. Commiehunter

    Commiehunter Been here awhile

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    The voltage drop is only at the injector plugs. From another source, this is likely due to the system signalling the injectors, with the injectors being grounded, and the volt meter can't adjust fast enough to read on/off.

    That said, I just got my injectors back from being bench tested and cleaned. All together and no fuel into the cylinders. I will check fuel pressure with a gauge next, but even low fuel pressure, I think it should start, but maybe stall on load.
    #13
  14. anytwowilldo

    anytwowilldo Adventurer

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    Did you get any info from the Previous owner that you feel is trustworthy? I would hit it with starting fluid to see if it starts and runs. That is at least a start. People reflash the ECUs on these bikes themselves. I've heard of this process going bad and people end up with a non running bike. There is a thread in here that discusses reflashing.
    #14
  15. Commiehunter

    Commiehunter Been here awhile

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    I asked PO. He didn't reflash it. He had ridden it for some time and "it stopped one day". He says no flash or map that he put on. I don't have reason to disbelieve this.

    Right now I've got 47-50psi from the fuel pump when I turn the key on.

    I don't know if I should smell gas from the spark plug hole if the injectors are working, or if it's too small a volume to notice.
    #15
  16. anytwowilldo

    anytwowilldo Adventurer

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    OK, How many miles are on it? Have you run a compression test? Again, hitting it with starting fluid will remove the fuel system from the equation and only takes a few minutes. If it starts, runs and sounds good on starting fluid, you can focus your attention on the fuel system.
    #16
  17. Commiehunter

    Commiehunter Been here awhile

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    I'm borrowing the compression test tool today. I didn't have starting fluid, but it didn't start with a bit of wd40. Could have been low cranking speed by then. It was the end of the night. I'll report back.

    36k miles.
    #17
  18. Commiehunter

    Commiehunter Been here awhile

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    Aha! It runs on seafoam! It seems to keep running for a while. Maybe until the seafoam runs out? This is the first time I've run a bike on a manual combustion source so I'm not sure how long it should run but it does. Seems to run pretty well other than the white smoke.

    So: injectors don't give me enough gas to start. Eh?

    I'm gonna go through the wiring and try and see if there's a ground somewhere there shouldn't be. It's my only hope at the moment.
    #18
  19. Rharr

    Rharr Been here awhile

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    simple test jig would be to pull the throttle bodies from motor, turn on it's side and install injectors hook up the needed wires and watch injector ends for gas spray as you run your tests.
    #19
  20. Commiehunter

    Commiehunter Been here awhile

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    How is this different from free floating injectors plugged into the harness? They didn't spray gas then.
    #20