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1G ARC-2 CDI Questions

Posted by RT-AWD, Sep 15, 2018

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  1. RT-AWD

    RT-AWD Proven Member

    337
    0
    Joined Apr 28, 2007
    Norristown, Pennsylvania
    Spark notes:
    Installed arc-2
    Tach not working
    Car breaks up really bad
    Its a 1991

    Hello all,
    Last night i spent a solid 3 hours wiring up this CDI box to hopefully fix an occasional breaking up issue (spark blowout). I got everything wired correctly and noticed right away my tach wasnt working?! Figured, ah screw it lets go for a spin and see if the car performs better.. its MUCH worse. Car breaks up at about 15psi now (used to be at 25psi at around 6k). I have my setting on the box to crank, rising edge, and restrike.
    I did not use the launch control, timing retard, or tach wire. The diagrams didnt even show these and i have all that stuff (besides tach) setup on DSMLink, so i thought i didnt need them.
    What do i need to do? Also, i have a sparktech COP that i didnt put in.. would that be beneficial or no? Seen mixed opinions on COP with CDI
     

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  2. Boomdeeze

    Boomdeeze Proven Member

    1,472
    178
    Joined Jul 5, 2009
    Independence, Minnesota
    Check your ignition timing, I had to redo mine after I installed my ARC-2 or else it was missing.
     
    My DSM:
    1997 Mitsubishi Eclipse GSX

    Street Build

    10.793 @ 128.98 MPH
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  3. ChessmoDSM

    ChessmoDSM Proven Member

    155
    87
    Joined Apr 22, 2017
    Burlington, Vermont
    I have actually heard the opposite, COP without CDI does not run the best, CDI combined with COP however is really good, that is what I currently run in mine..
     
  4. 19gsx91

    19gsx91 Proven Member

    929
    262
    Joined Apr 20, 2011
    Walworth, New York
    ARC 2 compliments a COP setup, mine ran pretty smooth until some wires wore bare and started arcing. I'm running the ARC-2 hooked up to the stock coil and its working pretty good for me, did idle a bit smoother with COP but that's about it. I can't remember what mine is set it. if the tach isn't working its because that small tach adapter box is bad.. if you did any searching you'd notice that's the first thing people complain about.
     
    My DSM:
    1992 Mitsubishi Eclipse GSX

    Street Build

    292 whp   264 lb/ft
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  5. brads

    brads DSM Wiseman

    781
    48
    Joined Oct 24, 2002
    Alta Loma, California
    Did you use the install harness that was designed for DSMs? It looks like you didn't, since you posted that wiring diagram.

    The install harness is designed to give a tach signal back to the PTU, so that the tach works correctly. If you don't use the install harness, you have to wire the tach output from the ARC-2 in as well.

    Do you have a timing light? I suspect you have something miswired on the install. This should be obvious when you try to check your timing.
     
    My DSM:
    1995 Mitsubishi Eclipse GSX

    Street Build

      manual
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    SAKJR likes this.
  6. RT-AWD

    RT-AWD Proven Member

    337
    0
    Joined Apr 28, 2007
    Norristown, Pennsylvania
    All, so an update, i installed the wrong harness. Last night i got the new correct harness and installed it. Tach is now working and car runs better however still hitting what feels like fuel cut at 20psi and building and about 6k rpm. I didnt remove the little black box capaciter on the coilpack and havent put in the COP yet. Im going to put in the COP and see if it improves.

    Settings are
    Restrike
    Crank
    Rising edge
    Rpm limiter i have off and timing ret i have off
    All this i have setup on dsmlink
     
    Last edited: Sep 19, 2018
    My DSM:
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  7. motomattx

    motomattx Proven Member

    995
    199
    Joined Dec 9, 2010
    wampum, Pennsylvania
    I would shut the restrike off, mine ran like crap with it on.
     
    My DSM:
    1995 Mitsubishi Eclipse GST

    Drag Race Build

    GT42   manual
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  8. brads

    brads DSM Wiseman

    781
    48
    Joined Oct 24, 2002
    Alta Loma, California
    That capacitor is on the 12V wire on the stock ignition. When you wire the ARC-2 up with the plug in harness, that should change that 12V wire to a ground wire, so the capacitor is basically grounded on both sides. It shouldn't affect things, but it can't hurt to remove it anyhow. On some of the early cars(90 I think), I think there is a tach adapter on the coil signal side, and that definitely does have to be removed.

    New plugs and wires? Have you tried lowering the plug gap to see if it gets better?


    Restrike really shouldn't cause it to run worse, unless you have some other issues, probably wiring. All it does is add a few more sparks after the main one, which can be good for lean running/idle/cruise.
     
    My DSM:
    1995 Mitsubishi Eclipse GSX

    Street Build

      manual
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  9. motomattx

    motomattx Proven Member

    995
    199
    Joined Dec 9, 2010
    wampum, Pennsylvania
    It caused it to run poorly at idle, Im not alone in that though, I have known others with the same issue, the wiring is new so I know its not a problem, and it runs fine with the cdi bypassed, I of course run full standalone and can log anything and everything and theres nothing notable going on, I dont think the 4g63 does well with restrike for some reason, it might be a flame propagation issue or something.
     
    My DSM:
    1995 Mitsubishi Eclipse GST

    Drag Race Build

    GT42   manual
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  10. brads

    brads DSM Wiseman

    781
    48
    Joined Oct 24, 2002
    Alta Loma, California
    The successive sparks on the ARC-2 at idle are several degrees apart, almost a full millisecond between them. I would be surprised if the second spark that much later made a big difference.

    Your standalone is logging timing, correct? Does it actually monitor the output from the ECU? Or is it logging the timing value it calculates? Even if it did actually monitor the output, it wouldn't see anything past that, unless you have additional logging monitoring the output of the CDI. As an example, if you wired in the timing retard on the ARC-2 and activated it, would you see any difference in the ignition timing value shown in your ECU? What I am getting at is that anything going on in the ignition wiring past the ECU is largely invisible to the ECU. Logging would catch problems with stray noise affecting other sensors though.
     
    My DSM:
    1995 Mitsubishi Eclipse GSX

    Street Build

      manual
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  11. RT-AWD

    RT-AWD Proven Member

    337
    0
    Joined Apr 28, 2007
    Norristown, Pennsylvania
    Got everything hooked up and put in my COP noticed a sputter accelerating just at a cruise. Popped the hood and the led was not on. Switched to restrike and the led came on... bad box?
     
    My DSM:
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  12. Vegas smith

    Vegas smith Proven Member

    2,151
    936
    Joined Dec 2, 2002
    Houston, Texas
    The chances of you having a bad box is extremely unlikely (sarcasm).
     
    My DSM:
    1993 Eagle Talon TSi AWD

    Street Build

    GT30   manual
    1992 Eagle Talon TSi AWD (sold)

    16g   manual
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  13. ChessmoDSM

    ChessmoDSM Proven Member

    155
    87
    Joined Apr 22, 2017
    Burlington, Vermont
    Did you purchase this new or used? There have been some issues here and there, I purchased mine brand new from Extreme PSI, no issues yet..
     
  14. brads

    brads DSM Wiseman

    781
    48
    Joined Oct 24, 2002
    Alta Loma, California
    That doesn't sound like the way the LED should operate. But it's been a long time since I worked on that project, and the LEDs may operate differently now. Contact Dynatek and ask them.
     
    My DSM:
    1995 Mitsubishi Eclipse GSX

    Street Build

      manual
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  15. amsrn13

    amsrn13 Proven Member

    1,856
    460
    Joined Dec 1, 2013
    danbury, Connecticut
    The light is on as soon as the unit is powered.
     
    My DSM:
    1992 Eagle Talon TSi

    Street Build

    645 whp   498 lb/ft
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  16. RT-AWD

    RT-AWD Proven Member

    337
    0
    Joined Apr 28, 2007
    Norristown, Pennsylvania
    The unit was purchased brand new from extremepsi. I was cruising home and came across a buddy and while playing in mexico, the car could not go above 4500 under heavy throttle and boost. It voilently breaks up each time. Im going to call them tomorrow
    When i got home the LED was on but flickering. I have my idle set to 750
     
    My DSM:
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  17. We're on Boost

    We're on Boost Proven Member

    827
    43
    Joined Aug 25, 2007
    Seattle area, Washington
    With the ARC-2, do you still need the stock power transistor? Or can you eliminate that and run straight from the ecu to the ARC-2?
    In the ARC-2 install manual it says "If installing on a vehicle with a power transistor, you have 2 choices. You can install the ARC-2 between the power transistor and coil, and set it up like a standard coil. Or you can remove the power transistor, and wire the ARC-2 directly to the ECU and coil, and set the ARC-2 up as if you were replacing a coil w/driver."

    But I wonder which way works better on our cars.


    Also, if the ARC-2 really does output something like 500 volts to the coil, how can that be OK with a stock coil pack? Doesn't the coil pack normally only get 12 volt pulses from the PT?
     
    Last edited: Oct 21, 2018
    My DSM:
    1990 Eagle Talon TSi AWD

    650 whp   510 lb/ft
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  18. brads

    brads DSM Wiseman

    781
    48
    Joined Oct 24, 2002
    Alta Loma, California
    If you want to install it the way I designed the ignition to be installed, you leave the power transistor in place. You use the plug in harness that plugs in right at the coil pack, and make installation a breeze.

    I say that it works better to leave all stock stuff in the car. Other people say to remove the power transistor because it isn't reliable. But the transistor should help to isolate the ECU from some of the electrical noise during firing/charging. and it should provide a stronger signal to the ARC-2 to fire.


    With a standard ignition, the coil pack generates a voltage spike of up to 400V on the coil negative when it fires. That is how inductive ignitions work. The CDI is just generating that spike from the ignition, instead of inside the coil. I think if you can find a copy of the ARC-2 manual, you can see a description of that.
     
    My DSM:
    1995 Mitsubishi Eclipse GSX

    Street Build

      manual
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  19. We're on Boost

    We're on Boost Proven Member

    827
    43
    Joined Aug 25, 2007
    Seattle area, Washington
    OK thanks for the good info!
    I looked for the plug-in harness on the Dynatek web site and couldn't find it. In fact the oldest DSM they let you even search for there is 1995. (My car is a 1990).
    Anyway, I would like to see a good pic of the harness if there is one made for 1990. I mean, my coil pack, PT, ecu, engine wire harness, and instrument panel are all 1990 in my 1990 Talon.
    But if I do an ARC-2, I probably would want to do it together with a COP setup.

    Are you one of the original designers of the ARC-2 unit?

    "if you can find a copy of the ARC-2 manual" LOL, yeah, I wasted about 15 minutes trying to find one on the Dynatek web site and could not find one.
    But I have one, "DARC-2 NEW INSTALL.pdf" that I got in 2014 via email from Larry Nelson at Dynatek Tech Support.
     
    My DSM:
    1990 Eagle Talon TSi AWD

    650 whp   510 lb/ft
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  20. brads

    brads DSM Wiseman

    781
    48
    Joined Oct 24, 2002
    Alta Loma, California
    Yes I was one of the original designers, left there a little after it was released. My car was the one in the install pics, I don't know if they ever updated that. Larry isn't there anymore either.

    IIRC, the 95-99 kit includes the mounting bracket for the unit, and a harness. The harness will work on the 1991-94, no changes needed. It plugs in at the 3 pin coil connector and gets all the signals there. It has a small tach adapter built in. This makes it so that your tach should work, and everything should plug in no splicing needed.

    It works on the 90 too, with just a little change to account for the 4 pin connector on the coil(the 91-99 all use a 3 pin connector). There have been a few people on here who have done it and posted threads on it that would have all of the specifics.

    The Dynatek website never was easy to navigate to get to the instructions. I have had better luck pulling them off the RoadRace Engineering website when I need to find them.
     
    My DSM:
    1995 Mitsubishi Eclipse GSX

    Street Build

      manual
    Loading...
  21. We're on Boost

    We're on Boost Proven Member

    827
    43
    Joined Aug 25, 2007
    Seattle area, Washington
    Ok, thanks Brad!
     
    My DSM:
    1990 Eagle Talon TSi AWD

    650 whp   510 lb/ft
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