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  1. R

    Cummins VT555 tachometer reading half RPM

    Thanks, I guess I'll have to borrow a tach meter and see what it says, the scope signal is sort of W shaped, so maybe its off the alternator, though don't know if that's why it's called a w signal.
  2. R

    Cummins VT555 tachometer reading half RPM

    Yes it has a DIP switch with the 4 positions, its on the max, all other settings give lower readings. No idea where the tach signal comes from as haven't traced the cable to the sensor yet. As both engines produce the same half RPM readings, I've assumed that the problem is that the replacement...
  3. R

    Cummins VT555 tachometer reading half RPM

    No idea, I put a scope on the tach signal and its a steady pulse, at idle about 10 hz if I remember right. So 10 a second, gives 600 rpm, but it shows 300 on both tachs.
  4. R

    Cummins VT555 tachometer reading half RPM

    New tachometers were installed by a previous mechanic but they indicate half the actual RPM. Tried adjusting the tachometer settings but won't go higher. Both engines are the same. Anyone know what tachometer is compatible, or if something can be adjusted on the engine?
  5. R

    Cummins VT555 low power & smoke

    That's good to know! I'll be spending more time to revise the procedures.
  6. R

    Cummins VT555 low power & smoke

    Thanks, that's very useful, didn't think about the rings squashing, makes sense. I'll check the vent lines for blockage, and get the level down to keep the fill tube empty. I'll was thinking a bad seal was feeding exhaust gas back to the tank as the fuel is getting warmed. Not sure I understand...
  7. R

    Cummins VT555 low power & smoke

    The original rings fully filled the grooves, they're black, oval shaped. One tank is getting enough back pressure to spray fuel out of the vent, they'd overfilled the tank, right to the cap. I'll check the book and fing the pressure connection, and buy a Guage. I'll check the cups in the head next
  8. R

    Cummins VT555 low power & smoke

    Thanks, me too, would be good to get this fixed.
  9. R

    Cummins VT555 low power & smoke

    The push rods got bent by adjusting them at the wrong points, early history I don't have, they say both engines were fine for years, then started smoking, so a mechanic said he'd change the injectors. Don't think he was really in top of the job if you know what I mean. Engines sound good, port...
  10. R

    Cummins VT555 low power & smoke

    Not sureWe had mechanic on the job, he recommended changing the injectors, but he made it worse, even bent pushrods, so I was asked to check it over, finding he hadn't started at TDC Cyl. 1, so messed it up. I did it by the book, and there's no smoke at idle now, only under load. It's grey...
  11. R

    Cummins VT555 low power & smoke

    Hi, I'm trying to resolve a power loss issue on our VT555 and would appreciate any advice as I'm new to this engine. I've reset the injectors and valves as per the book and it runs sweet, and no smoke even at high RPM untill we put it under load. Turbos can be spun by flicking with the finger...
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