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Ignition question on TR

Discussion in 'Technical Q&A' started by henryk, Jun 20, 2005.

  1. henryk

    henryk Formula Junior

    Dec 9, 2003
    479
    Door County, WI
    I am trying to hook up a lab scope to the ignition of my TR. The instruction state that the red probe goes to the primary, while the blue probe goes to the secondary.

    Which wires are these on the ignition coil?

    Thanks.
     
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  3. Steve Magnusson

    Steve Magnusson F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    19,871
    Texas
    Full Name:
    Steve Magnusson
    Hank -- The terminal of interest for the coil primary winding is the minus side (#1 terminal, red wires) -- it will spike up to 200~400 volts when firing occurs. Is the "red probe" a direct electrical connection?

    IME with these testers (which isn't that extensive in this case) there is no direct connection to the secondary winding (and there's only one terminal to access on the secondary winding anyway -- which is where the coil ignition wire that goes to the distributor cap connects). Is the "blue probe" a clamp-on inductive arrangement that goes on the coil ign wire? (I.e., I would not make a direct electrical connection to the coil secondary side -- too dangerous.)
     
  4. henryk

    henryk Formula Junior

    Dec 9, 2003
    479
    Door County, WI
    The red and blue probes are direct wire-type connectors. I think they are referring to the "old" style ignition system.

    The kit also comes with other probes: One is labeled "KV Probe for Scope".......a metal tube-type connector, designed to go over a wire, without punture. The other is labeled "Sync Probe for Scope".......a plastic inductive-type pickup, with one side labeled "spark plug side".

    This is an OTC brand scope, with no manual............It is supposed to be user friendly!!!!!!!!!!!!! To a mechanic that uses this all the time, they may be correct. But, I am just learning these things, and trying to apply them to a Ferrari!!!!!!!!!

    My first step is to check the #15 terminals on the coils, to see if I get 12V in each. My right side is not firing.
     
  5. Steve Magnusson

    Steve Magnusson F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    19,871
    Texas
    Full Name:
    Steve Magnusson
    No instructions is a bummer.

    The "KV Probe for Scope" is the only thing that I'd try hooking to (really around) the secondary coil wire. Does it seem logical from the constructions that the "KV Probe for Scope" (and the "Sync Probe for Scope") could be used in conjunction with the "blue probe" rather than instead of the blue probe?

    You can always try just using the red probe hook-up and see if will measure something (and I assume that there's some sort of constant "power" and "ground" connections to run the instrument also?), but I still don't like the thought of making a direct electrical connection to the coil secondary.
     
  6. henryk

    henryk Formula Junior

    Dec 9, 2003
    479
    Door County, WI
    I agree..........I have no intention of puncturing ANY wire. I have a separate KV measuring instrument, which I will use first. It seems that the scope part is best used once the engine is running......IMO.

    Using the KV tester, with a tube-type clip over the coil wire, I got readings on the left side, but none on the right.......when the engine was running on only the left bank.

    I switched the coils around, and still only the left side shows KV voltage (38KV high, and 5.4KV low)..........however, the engine didn't start. So I have a possible fuel problem also. Both fuel pumps work.

    My plan is to start with the basics, and work on the ignition first:

    1) I checked all connections, and no "pins" are bent, etc.

    2) With ignition on......I got 12+V at the #15 wires, going to each coil.

    3) Plug wires, spark plugs, caps and rotors where replaced during the major, with new parts.

    Tomorrow, I will remove the spark plugs, and lay them on the engine and see if I get a visual spark.

    I will be getting a remote starter tomorrow morning, from the Matco rep. It is hard to have to get into the car to crank the engine, while trying to test things in the engine compartment.

    Can you tell me how to hook up the remote starter, Steve?

    Thanks,

    Hank
     
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