COP's . . . resistor plugs on 355? 308 cop still don't work | FerrariChat
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COP's . . . resistor plugs on 355? 308 cop still don't work

Discussion in 'Technical Q&A' started by luckydynes, May 13, 2007.

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  1. luckydynes

    luckydynes F1 Rookie

    Jan 25, 2004
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    #1 luckydynes, May 13, 2007
    Hey all,

    Still didn't get my COP conversion working . . . I have yet to shield all the wires although I did wrap most of the loom in tin foil which should've simulated things pretty well . . . couldn't get to the entire loom but I may cut the loom up to shield everything better if this doesn't work . . .

    Do the 355's have resistor plugs?

    I'm running stock plugs in my 308 which I don't think are resistor . . . resistance is in wires . . . right? Should I order NGK resistor plugs with the same number as what I have? I think they're BP7ES if I'm remembering right.

    Just in case you're wondering why I'm asking about the 355 is because there's been several successful COP installations on them . . . and some unsuccessful though.

    Thanks,

    Sean
     
  2. luckydynes

    luckydynes F1 Rookie

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    #2 luckydynes, May 14, 2007
    I think I'm on to something here . . . there would be a ton noise affecting the Haltech ECU using the cop's on standard plugs . . . going to try it.

    Sean
     
  3. treue

    treue Formula Junior

    Jan 22, 2004
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    #3 treue, May 14, 2007
    Sean,

    Original 308 plugs are not resistor-type because the wires and extenders ARE. The extenders should have about 1100 ohms and frequently go bad. The carbon-core wires won't last forever, either. My 308 ran fairly well on just four cylinders.


    Tom
     
  4. luckydynes

    luckydynes F1 Rookie

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    #4 luckydynes, May 14, 2007
    Another reason I'm hoping to get this COP working . . . no more distributor caps, wires, or extenders.

    I'm real hopeful the resistor plugs do it.

    Sean
     
  5. Paul_308

    Paul_308 Formula 3

    Mar 12, 2004
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    #5 Paul_308, May 15, 2007
    What pray tell is a 'COP' ??
     
  6. Etcetera

    Etcetera Two Time F1 World Champ
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    #6 Etcetera, May 15, 2007
    Coil On Plug conversion.
     
  7. luckydynes

    luckydynes F1 Rookie

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    #7 luckydynes, May 27, 2007
    Resistor plugs did it!
     
  8. jeffdavison

    jeffdavison F1 Rookie

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    #8 jeffdavison, May 27, 2007
    I believe I'm the first to concieve and perform this conversion and it's been running absolutely perfect over 2 years now with absolutely no problems on the street or track.

    JD
     
  9. luckydynes

    luckydynes F1 Rookie

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    #9 luckydynes, May 27, 2007
    Yes you were and thanks!!! . . . your thread motivated me and even got me 4 coils from another chatter!!!


    Glad to hear all is still working properly. I thought I recall several other people having problems to the point that $1k+ for plug wires seemed cheap again. A guy with a Countach, aftermarket EFI, and two DIS4's never could get it working. I started thinking it was shielding (I think you used shielded wire) and had numerous conversations with MSD about it. Switching to resistor plugs from the standard plugs seems to have solved my problems. I'm also using a Haltech ECU which I'm sure is more sensitive to high voltage than the 355 ECU.


    So do the 355's use resistor plugs?



    Sean
     
  10. luckydynes

    luckydynes F1 Rookie

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    #10 luckydynes, May 27, 2007
    There's an output on the DIS4 box for rpm but the stock tach reads double . . . isn't there some "tach signal conditoining box" that I can use instead of having the tach recalibrated?

    Thanks,

    Sean
     
  11. f355spider

    f355spider F1 World Champ
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    #11 f355spider, May 27, 2007
    Yes, 355's use resistor plugs. NGK PMR7A is the stock oem plug.
     
  12. mk e

    mk e F1 World Champ

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    #12 mk e, May 28, 2007
    Sean, just use an output from the haltech to drive the tach if any are available. The 308 tach is tough because it's a 4 cylinder tach, not an 8 due to the twin distributors. They used to sell an adapter to cure this in the motorcyle world, you could search there too.
     
  13. luckydynes

    luckydynes F1 Rookie

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    #13 luckydynes, May 28, 2007
    Still need the adapter to split the number of pulses in half. I'm surprised I couldn't adjust this in the Haltech software. Anyway, looks like I found what I needed on another Fchat thread . . . Dakotadigital.com has "universal tach signal interface".

    Another interesting development . . . I've been able to dial in another 8 degrees of advance with this ignition system (36 degrees full advance with 10.5:1 compression, was pinging with dizzy's over 28 degrees) . . . maybe some cross talk or noise from the plug wires was causing some erratic spark or does the CDI spark help suppress detonation?

    Sean
     

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