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Ignition module failure question

Discussion in 'Technical Q&A' started by JohnMH, Jul 31, 2025 at 7:08 AM.

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  1. JohnMH

    JohnMH Formula 3

    Jan 28, 2004
    1,824
    Bologna
    #1 JohnMH, Jul 31, 2025 at 7:08 AM
    My Testarossa and my early Diablo use the same coils and modules. When a coil or module fails (so far only on the TR) one bank goes down and I get a tow home. Once the TR drops a bank, it stays down.

    Yesterday the Diablo was traveling from Livorno to Bologna at, uh, Diablo speed. One bank shut down, then a few seconds later restarted. The Diablo expressed its displeasure by igniting all the unburnt fuel in the exhaust and nearly immolating the Audi behind it (that I was driving). Very frightening. We pulled over, stopped and the car restarted on 12. Weird.

    Cap, rotor, plugs and wires are all new. The only thing left are modules. When they go, do they come back?
     
  2. Drew Altemara

    Drew Altemara Formula 3

    Feb 11, 2002
    1,533
    Tuscaloosa, AL
    Full Name:
    Drew Altemara
    #2 Drew Altemara, Jul 31, 2025 at 11:12 AM
    Could be a cam or crank sensor going out. That happened on my F40. Cam positioning sensor went out on driver's side. Would come back on then finally went dead. Just another thing to check but I imagine you need a reader to get the code.

    Good luck.
     
  3. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,840
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    #3 Steve Magnusson, Jul 31, 2025 at 12:10 PM
    We haven't had a lot of reports (if ever?) of the modules coming and going. As Drew reported, some F models have an ignition architecture where a bad crank sensor can take out a bank (e.g., 308), but other F models don't (e.g., TR). There has to be something (ECU/ECUs) that "tells" the modules to fire so that has to be on your list, too. You might have a look at your Diablo schematic to see if it has separate flywheel (or cam) sensors for each bank, or not.
     
  4. JohnMH

    JohnMH Formula 3

    Jan 28, 2004
    1,824
    Bologna
    #4 JohnMH, Aug 1, 2025 at 12:54 AM
    Thanks for all the suggestions.

    These early 5.7 cars have a single crank sensor that supplies both ECUs, but two phase sensors on the driver’s side exhaust cam. The ECUs only recorded one error, lambda on the right side bank. Were the single crank sensor to fail, the engine would not run. Were the phase sensor for the right bank to fail, the right side ECU should record an error code (4 flashes) when interrogated. No such error.

    The fact that the engine runs on 6 for a few seconds, then runs on 12 (but then burns a lot of unburnt fuel collected in the exhaust) suggests an ignition issue to me. Am I missing another possibility? Fuel filters, pumps and fuel pressure regulators are new.

    Next stop is to look at the cap, rotor, coils and ignition wiring. I noticed that it first started acting up after the engine became quite hot, stuck in Livorno traffic. The next issue arose after an extended period at 180-200 km/h when the car slowed to 100-120 km/h in traffic. Heat may be associated with the issue.

    My pilotti friend (retired factory test driver) found the engine to be a good example of the breed when it was working properly.
     
  5. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
    37,116
    Cowboy Capitol of the World
    Full Name:
    Brian Crall
    #5 Rifledriver, Aug 1, 2025 at 7:46 AM
    I have seen a few transistor modules that failed intermittently but its not the common failure mode. As cheap as they are Id just replace them. On our LM002 they are in an area that does not get particularly hot, unlike the TR cleverly placed directly above the exhaust system.
     
  6. JohnMH

    JohnMH Formula 3

    Jan 28, 2004
    1,824
    Bologna
    #6 JohnMH, Aug 1, 2025 at 8:16 AM
    Haha. A Diablo places them inside the left rear fender behind the coils. I hate firing the parts shotgun at a Lamborghini. The intermittent nature of the problem means that I can only drive around and wait for it to happen.

    Might anyone know a good online source for these modules?
     

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