1.9 tdi ads-pre alpha 1.32 interrupt switch issue

Discussion in 'DIY Marinizing' started by Philip b16, Apr 8, 2021.

  1. Philip b16
    Joined: Apr 2021
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    Location: UK

    Philip b16 Junior Member

    Hello I have an old Winner 21 day cruiser which I bought 4 years ago with no engine or floors.
    It did however still have the stern drive (from an old v8 mercruiser)
    So my good friend installed a low mileage 1.9tdi (asz 130hp-tuned to 170hp) recently, and I have now completed the the floors and other bits and bobs to make the boat usable.
    The issue I need advice with is that the old petrol V8 system uses an ignition interrupt switch to enable the dog clutch to disengage when moving out of gear, obviously the tdi does not have a similar system.
    We have tuned the idle speed to 650rpm
    I am about to change the original prop(15 2/4 x 17) to a new smaller diameter one in an attempt to reduce the torque on the prop shaft at idle (15 x22)
    Please help I’m desperate to get this boat in the water.
    Phil b
     

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  2. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    It won't shift without the shift interrupt switch. You may be able to grind it into gear, but it will be virtually impossible to get it out of gear without turning off the engine. It is a mismatch of equipment.
     
  3. Philip b16
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    Philip b16 Junior Member

    Hi Gonzo, thanks for your reply, it goes into gear very easily.
    It’s getting it back to neutral is the issue at the moment, I was wandering if there is a way to micro stall the Vw 1.9 Tdi to mimic the interrupt switch on the mercruiser?
     
  4. gonzo
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    gonzo Senior Member

    The shift interrupt switch works by shutting off the ignition one every other cylinder. I think that the engine you have has a mechanical injection system. That would be hard to modify to make it miss every other stroke.
     
  5. tonipu
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    tonipu Senior Member

    try to disengage to shout off electromagnetic valve on the high pressure pump
     
  6. tonipu
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    tonipu Senior Member

    or is a electronic controled engine?
     
  7. Philip b16
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    Philip b16 Junior Member

    Hi Toni, thanks for your help, yes I believe it is run by the ecu
     
  8. Philip b16
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    Philip b16 Junior Member

    The engine code is ASZ
     
  9. gonzo
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    gonzo Senior Member

    The shift interrupt switch is connected to the ignitions and short every other cylinder. It makes the engine miss and allows the lower unit to get out of gear. I think this engine has a mechanical injection pump.
     
  10. tonipu
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    tonipu Senior Member

    Take a few picture of injection system, do you have Engine ecu, or not
     
  11. Philip b16
    Joined: Apr 2021
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    Philip b16 Junior Member

    Hi Tonipu, thanks for your help.
    Yes the engine has an ecu, I have taken some photos and I’ll try to upload a workshop type manual I have found online and believe is for my 1.9 asz tdi
     

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  12. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    It can be done, but will not be easy. You need to override the ECU and make the injectors misfire. However, that will create an error message. You may need to add a command to erase the error messages after each shift.
     
  13. baeckmo
    Joined: Jun 2009
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    baeckmo Hydrodynamics

    Naah, shouldn't be that difficult. Your engine has separate cam-operated injectors with control solenoids, not the VE pump shown in another post above. For instance, there are signal senders for clutch and brakes that reduce injection volumes temporarily included in some ecu's. Send a message to forum member Anthony Goodson, he may have some clever trix up his sleeve.
     
  14. Philip b16
    Joined: Apr 2021
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    Philip b16 Junior Member

    Thanks baeckmo, that sounds very easy lol, I’ll mention it to the guys trying to help me
     

  15. Philip b16
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    Philip b16 Junior Member

    I have messaged Anthony but it looks like he’s not been active for a while now.
     
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