T3 1992 Carvelle 2.1mv NO SPARK

Discussion in 'T3 & T4 Tech Help Clinic' started by Al Sweeney, Jan 8, 2018.

  1. Al Sweeney

    Al Sweeney New Member

    Messages:
    6
    Location:
    Brisbane
    I have spent my Christmas Vacation with our beloved Van and need some help please trouble shooting the fault.

    My questions:

    Where is the ECU relay and how to check if a signal is getting to the coil?
    How to reset the ECU?

    Here are facts:
    RACQ genius deducted the Hall sensor was faulty surprising it was a new one that ran fine for the last week along with new coil (yes Green but ohm reading is a bit out). Tested fuel pressure in fuel rail behind distributer. Hall replaced and can confirm it works with Voltage multimeter. There is no spark direct from coil HT to ground. Swapped coil , no joy there. Yes removed battery earth every time touched electrical. Charged battery.

    Feel free to text or call 0408770910.

    Cheers Al
     
  2. Luckyphil

    Luckyphil Well-Known Member

    Messages:
    5,183
    Location:
    Gosford
    have you tried another lead from the coil, they do fail as well.
     
  3. Luckyphil

    Luckyphil Well-Known Member

    Messages:
    5,183
    Location:
    Gosford
  4. Barry

    Barry Well-Known Member

    Messages:
    1,918
    Location:
    Abbotsford NSW
  5. gazman

    gazman Well-Known Member

    Messages:
    1,737
    Location:
    Perth WA
    There's a few types, AFAIK the earlier T3's had the one that is integral with the breaker plate (both links above), and the later ones were separate like this one -
    [​IMG]
     
  6. Al Sweeney

    Al Sweeney New Member

    Messages:
    6
    Location:
    Brisbane
    I have tested the HT leads comes up to spec, checked voltage on hall sensor and the return output changes voltage when rotate the distributor so assume the Hall is functioning, checked voltage on ECU relay is 12v , fuel relay nil as ECU controls that and can hear fuel pump prime when ignition turned on. It is a T4 hall sensor in it currently.

    Next step to reset ECU any help there would be appreciated or a digifant manual in PDF would be sweet and I will read up voltages on terminals of the ECU.

    I did notice the anti stall was constantly buzzing which appears to be unusual to me, is it supposed to stay on with the ignition turned on but not started.

    Any help or suggestion are appreciated apart from burning it as we love the old bus.
     
    Last edited: Jan 9, 2018
  7. Luckyphil

    Luckyphil Well-Known Member

    Messages:
    5,183
    Location:
    Gosford
    Is it possible that when hall sender last replaced the dizzy was put back together incorrectly ie 180deg out
     
    Syncro27 likes this.
  8. hairyman

    hairyman Active Member

    Messages:
    360
    Location:
    Sydney, NSW
    From what you say, it sounds like the dizzy is producing a signal but it isn't getting to the coil or the coil is not doing anything with it.

    Can you check the voltage at the coil as you twist the dizzy through the point the hall sensor gives a signal, to see if it is getting to the coil.

    From what I understand, I think the coil should get 12V across the two outer terminals until the hall sensor tells it to fire, at which point the 12V is interrupted causing the field to collapse and releasing the 20000V spark.

    That should tell you if you have a wiring failure in the loom somewhere or of the coil is knackered.
     
  9. hairyman

    hairyman Active Member

    Messages:
    360
    Location:
    Sydney, NSW
    Luckyphil likes this.
  10. Al Sweeney

    Al Sweeney New Member

    Messages:
    6
    Location:
    Brisbane
    Thank you Neil great reference , I checked if 12volts at coil with ignition on then with a LED between 1 and 15 (ciol primary circuit) that a signal was been sent and it looks like a faulty coil. Since my supplier is shut all I could find was a T4 coil at the recyclers. I am hoping to find the pin out on line today to connect it up. The faulty coil has the resistance reading out side of scope but not open which is confusing why.

    Cheers Al
     
    hairyman likes this.
  11. syncro

    syncro Well-Known Member

    Messages:
    8,533
    Location:
    Southern Highlands
    Using the wrong coil could cause problems. They really need to be matched.
     
  12. Al Sweeney

    Al Sweeney New Member

    Messages:
    6
    Location:
    Brisbane
    I got the bus started last night by using a T4 solid state coil but now trouble shooting the idle issue it appears to be surging or hunting which from my old carby days was to much fuel. So suspect the O2 sensor got fried. It must have been a bolt of lightening that hit me new years eve which explains my glowing smile new years day, lol.
     
    David H likes this.
  13. syncro

    syncro Well-Known Member

    Messages:
    8,533
    Location:
    Southern Highlands
    Just disconnect the O2 sensor and car will run fine.
     
  14. hairyman

    hairyman Active Member

    Messages:
    360
    Location:
    Sydney, NSW
    Remember that the O2 sensor reading is ignored by the ECU until the engine is warmed up. If the idle was hunting from start up it'll be something else.

    The T2 sensor on the thermostat housing might be the culprit? That can screw things around a lot.
     
    David H likes this.

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