675.cc • Triumph 675 Forum

Dead ECU?

Discussion in 'Maintenance & Tweaks' started by Vicolaships, May 14, 2019.

  1. Vicolaships

    Vicolaships

    Thread Starter

    9
    0
    1
    Location: France
    Hi there,

    I had a leaky fuel hose so I changed it. During the process the connector of the fuel pump disassembled: the wires went out of the connector.

    I tested the pump with my 12V battery to determine the polarity of the pump to spit out fuel then the polarity of the cables to assemble the connector again.

    [​IMG]

    After that I finished connecting everything and went for a test but the motorcycle doesn't start at all:
    • Fuel pump does not start
    • Neutral indicator does not light up (I have doubled checked the gearbox is in neutral)
    • The orange engine indicator does not stay on as it should.
    • The motor does not crank when the starter button is pressed (nothing happens at all, not even a relay sound)
    • Battery voltage is 12.8V (less than 6 months old), I have tested an other battery (12.6V) with no success
    Here is a picture of my dashboard when turning on the bike:
    [​IMG]
    Here is a very short video showing the startup of the bike: (the RPM needle never worked, so this is fine)
    https://send.firefox.com/download/d2acede7bc06a022/#k5BDwI4OLHnC_w0rYicLbg

    I have verified all the fuses and the relays (including starter) and they all are fine.

    I have three dangling connectors but I believe they were never connected in the first place:
    [​IMG]

    I have also tried to connect and OBD2 to the CAN bus of the motorbike but it fails to connect so it seems that the ECU is not responding. (the same OBD adapter works on my car).

    Is there anything I miss? Should the black/yellow connector be dangling? Is my ECU dead?
    Thank you for reading :)
     
  2. Vicolaships

    Vicolaships

    Thread Starter

    9
    0
    1
    Location: France
    Does anyone have an idea of what is going on? :rolleyes:
     
  3. StephenP

    StephenP

    1,775
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    Location: Hertfordshire
    I've had connectors go and rather than do what you did, I got an old loom and put new connectors in place after a little wire cutting.

    May be an option.
     
  4. StMarks

    StMarks PTG

    12,120
    808
    113
    Location: HU15 2DS
    Bonjour.
    I thought I'd already posted a reply to this, don't know what happened to it, sorry.:wall:

    Anyway.
    The fuel pump connector in the top image that looks melted. That is usually indicative of excessively high resistance in the circuit, causing heat & therefore damage.

    Your bike is an early one, and (like mine) has had a sub-loom added to the wiring harness to protect the ECU being fried by the fuel pump circuit. Instead of drawing the supply directly & via the ECU, the alteration takes the power from via a relay. However.:
    Those look like the connectors of the above mentioned sub-loom. The original harness plug should connect onto one, and the other one should connect onto the fuel pump.
    Because that has not been connected, I'm afraid I suspect that there is a good chance that the damage has been done.:((
     
  5. StMarks

    StMarks PTG

    12,120
    808
    113
    Location: HU15 2DS
  6. Astrav6

    Astrav6

    74
    4
    8
    Location: GB
    Have you checked the ecu fuse?
     
  7. Vicolaships

    Vicolaships

    Thread Starter

    9
    0
    1
    Location: France
    Thanks for your answers. The connector is not melted but has suffered some screwdriver aggressions :)
    I've measured the resistance of the fuel pump and it is within the advised range (2 to 6 ohm), I have 5 ohms. With the 12V battery it spits out fuel nicely so the pump looks ok.

    I have checked the fuses in the box and they all are good:
    [​IMG]
    I also checked the starter relay and fuse.
    Is there an other fuse I'm not aware of ?
     
  8. StMarks

    StMarks PTG

    12,120
    808
    113
    Location: HU15 2DS
    I wonder if I explained poorly Vicolaships.?
    The connector that has been mauled, should NOT be connected to the fuel pump. If it is, there is a strong probability that the ECU will be damaged.
    That mauled connector should plug into the white (you described as extra, unused) plug you found. The other Brown plug ( that is identical to the mauled one) that is next to the white one, should be fitted to the fuel pump connection.
    However, from your description of the problem, your ECU may already be fried. Hopefully not, obviously. :((
     
  9. Vicolaships

    Vicolaships

    Thread Starter

    9
    0
    1
    Location: France
    Thanks for the details. I'll fix the wiring, buy a new ECU and hope for the best.
    Of course, I'll keep you updated of my progress!

    :)
     
  10. StMarks

    StMarks PTG

    12,120
    808
    113
    Location: HU15 2DS
    Fwiw I'd try connecting the pump via the relay wiring first, just in case that gets you running.
    Also, unless you've got a source of well priced parts, it may be worth you placing a thread in the "Wanted" section on here for an ECU. They don't seem to go wrong often, so I imagine there must be quite a few spares out there.
     
  11. I have both generation ECU’s for sale if you need me to post you one @Vicolaships
     
  12. ive got ecu with wiring if you would need one ;)
     
  13. Vicolaships

    Vicolaships

    Thread Starter

    9
    0
    1
    Location: France
    I had already ordered a used ECU but thanks for the propositions ;)

    I have fixed the wiring with the new 2 connectors
    I have installed the new ECU (while no battery was connected).

    Exact same behavior with the new ECU:
    • Fuel pump does not start
    • Neutral indicator does not light up (I have doubled checked the gearbox is in neutral)
    • The orange engine indicator does not stay on as it should.
    • The motor does not crank when the starter button is pressed (nothing happens at all, not even a relay sound)
    • Battery voltage is 12.8V (less than 6 months old), I have tested an other battery (12.6V) with no success

    I'm still wondering about the black and yellow connector, what is this one and should it be connected ? Because it's not :p
    [​IMG]
    [​IMG]

    Any ideas of what may be wrong? What should I check next?
     
  14. StMarks

    StMarks PTG

    12,120
    808
    113
    Location: HU15 2DS
    Fwiw I'm afraid I don't recognise that plug @Vicolaships , which is why I hadn't referred to it before. It does look fairly critical, with 6x contacts.
    My fuel tank is fitted at present, so I'm unable to search it out on my own bike.
     
  15. Astrav6

    Astrav6

    74
    4
    8
    Location: GB
    What colour cables are on the connectors. Looks a bit like a regular/rectify connector

    Has the idle control been removed as could be for that.

    Have you checked the ecu fuse isn't blown?
     
  16. Vicolaships

    Vicolaships

    Thread Starter

    9
    0
    1
    Location: France
    The cable colours are:
    Pink/black
    Green/yellow
    Pink
    Green/white
    Green/blue

    [​IMG]
    [​IMG]

    For an unknown reason now everything works fine, I have just messed up with the cables to try to find a mating connector for the black/yellow connector.

    I suspect there's a false contact somewhere on the wiring but finding where is not going to be easy. I'll try to get the motorcycle running first and then make sure it's not going to shut down while i'm riding it :p
     
  17. In the mix

    In the mix

    190
    8
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    Location: Uk
    That connector is exhaust valve motor
     
  18. Vicolaships

    Vicolaships

    Thread Starter

    9
    0
    1
    Location: France
    That is right !! It has been left unconnected by the last owner. It was bit hard to reconnect but I managed. The valve motor doesn't seem to move but I'll check that later.

    I re assembled everything and the bike is running.

    The wires in the fuel pump connector had to be pushed all the way inside the connector with a small screwdriver otherwise there was no electrical connection.

    Thank you all for the help !
     

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