Ignition trouble on my 328 gts from -87 | FerrariChat
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Ignition trouble on my 328 gts from -87

Discussion in 'Technical Q&A' started by Stefan_328, Apr 22, 2006.

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  1. Stefan_328

    Stefan_328 Rookie

    Nov 2, 2004
    12
    #1 Stefan_328, Apr 22, 2006
    Finerly the spring is here :)

    But i still have some problem with my Ferrari 328 gts.
    The engine missfire on some cylinders. I can´t see any change in color on the sparkplugs. When it´s warm and dry outside the engine works great.
    When it´s some mousture in the air it goes on 6,7 cylinders.
    I checked with ocioloscope in the test plug and checked sensors and ignition unit. They works ok! I cleaned rotor and distrobuter cap when i change the cam belts and after that i got the problem.
    I also change the sparkplugs, ignition leads still the same problem.
    Rotor and distributer cap cost a lot so i don´t want to change it if i don´t need to. Any ideas? I can´t see any thing wrong with the distributor cap.
    Should i change it anyway? Rotor and cap cost over 600 dollars :(
    I can get a lot of fuel for that.

    Thanks for your help!

    Stefan/ Sweden
     
  2. hardtop

    hardtop F1 World Champ

    Jan 31, 2002
    11,294
    Colorado
    Full Name:
    Dave
    #2 hardtop, Apr 22, 2006
    Could be your distributors, but first I would buy a new spark plug extension or two and try them in the offending holes.

    Dave
     
  3. Darolls

    Darolls F1 Veteran
    BANNED

    Jul 2, 2003
    7,782
    Full Name:
    Sparky
    #3 Darolls, Apr 22, 2006
    Put a few wraps of electrical tape on the extenders.

    If that corrects the problem, replace the extenders or, leave the tape on and drive until the problem occurs again.
     
  4. 4redude

    4redude Formula Junior

    Jan 13, 2005
    732
    Fungus Corner
    Full Name:
    Brian Keegan
    #4 4redude, Apr 24, 2006
    I'm not sure if this is relevant, but there was a Service Bulletin (#80-24)pertaining to Digiplexes and unusual anomolies for 328/3.2 Mondials. It involved buying a 120307 protection diode and installing it (wiring diagram provided). Part is under $5.00. The other thing to check is the power modules (black plastic part) on top of the coils. These seem to fail more than the coil itself, but Ferrari only supplies the entire $600 coil. These modules are available separately in either a Marelli or Bosch component, but not from Ferrari. We stock all of the above components here a T.Rutlands.

    Brian
    [email protected]
     
  5. Iain

    Iain F1 Rookie

    Jan 21, 2005
    3,320
    UK
    #5 Iain, Apr 24, 2006
    First thing to do would be to get an inductive timing light i.e. a timing light where the signal cable just clips over a plug wire & not one that goes in line with it - not expensive.

    To get power for it you can use the number plate light feed on the right side of the rear deck - just unplug the connector & turn the sidelights on. Ground it anywhere sensible.

    Once you've got that working then you can test each cylinder in turn and each bank in turn & you should be able to narrow it down quite quickly as to whether you are losing one or more cylinders or an entire bank.

    If its a single cylinder then start at the rotor arm & work forwards i.e. rotor, disty cap, plug lead, extender, plug. Swap some parts around & see if you can get the problem to move.

    If its a bank then start at the rotor arm and work backwards. Swap parts from one bank to the other to see if you can move the problem with a part - i.e. swap the rotor arms over & if the problem moves then you know its a rotor arm - same with the disty caps, leads from coil to cap & ultimately the coils.

    If its none of the above then maybe look towards the cranbkshaft sensor(s).

    HTH

    I.
     
  6. Stefan_328

    Stefan_328 Rookie

    Nov 2, 2004
    12
    #6 Stefan_328, Apr 25, 2006
    Thanks for all the tips you give me.
    Can the ignition module give a fault how is intermittent?
    I have checket all sparkplugs several times. I can´t see any diffrent color on them. I have checked with stroposcope lamp and today it was no problem but the car runs a bit ruff. I can´t here any diffrent but it vibrates att some rpm. And the sound is not right and loss of 50-70 bhp.
    When the sun is out and it´s dry air it works. But if i drive in to bad weather it´s comming back.

    I keep on looking....

    Stefan
     
  7. Verell

    Verell F1 Veteran
    Consultant Owner

    May 5, 2001
    7,022
    Groton, MA
    Full Name:
    Verell Boaen
    #7 Verell, Apr 25, 2006
    Usually humidity related problems are in the high voltage wiring. The humidity will encourage arcing to ground.

    Here's a trick: Start the car at night in a dark garage & see if you can see a spark coming from somewhere in the ignition wiring.

    The inductive timing light will tell you if current pulses are going thru the lead it's attached to. If all the leads check OK, then the problem is most likely inside the spark plug wells, either the insulating boot, the extenders, or the plug itself.

    It's pretty common for one of the stand-offs to develop a pinhole burn-thru. Usually you can see a small (~1/8") dark smudge on the inside of the stand-off, & a tiny black pinhole on the outside. I've drilled out the pinholes & repaired the insulator with epoxy or silicone. However, I don't know why humidity would be a factor.

    If you can't find it, a shop with an ignition oscilloscope should be able to pinpoint the problem cylinder(s) right away. Might be worth their diagnostic fee to get a quick answer.
     

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