1. Registration trouble? Please use the "Contact Us" link at the bottom right corner of the page and your issue will be resolved.
    Dismiss Notice

No spark question

Discussion in 'Intermediate CJ-5/6/7/8' started by 74Cjake5, Mar 13, 2014.

  1. Mar 13, 2014
    74Cjake5

    74Cjake5 Member

    louisville colorado
    Joined:
    May 30, 2011
    Messages:
    102
    Last summer I installed a msd 6a in my 74 w/ a 304. I drove it around a little wih no issues and nothing but good feelings abou the upgrade. parked it and let it sit until now, as life got moe busy and important than the jeep. I finally got the time to fiddle with the jeep again and I have found that I now have no spark... I looked up how to test the 6a for spark and followed those directions and I got spark (6a module is fine) I am not getting any spark to the plugs when I crank however. When I added the 6a I changed out the cap for a new grey cap and a new grey rotor, as well as adding 8mm spiral wound wires. My question is; Should I suspect the distributor itself? Or look for a different cause? Maybe new points? not sure exactly where to go from here...
    Thanks, Jake
     
  2. Mar 13, 2014
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
    Joined:
    Sep 23, 2002
    Messages:
    11,539
    Have you visually inspected points,cap, rotor, etc. for corrosion?


    Sent from my iPhone
     
  3. Mar 13, 2014
    74Cjake5

    74Cjake5 Member

    louisville colorado
    Joined:
    May 30, 2011
    Messages:
    102
    Yes, no visible corossion.
     
  4. Mar 13, 2014
    PeteL

    PeteL Member 2020 Sponsor 2019 Sponsor

    Hills of NH
    Joined:
    Aug 3, 2003
    Messages:
    6,701
    If its been sitting, maybe the point contacts oxidized? Did you try cleaning and setting them?
     
  5. Mar 14, 2014
    jeepcj

    jeepcj Member

    cincy, Ohio
    Joined:
    Aug 23, 2009
    Messages:
    601
    I would suspect the points and condenser as well. You should be able to turn the ignition on (engine off) and manually snap the points open and closed, you should see a spark if they are good. No spark or very weak spark, get new points and condenser.
     
  6. Mar 14, 2014
    Corveeper

    Corveeper Member

    Chanute, Kansas
    Joined:
    Jul 29, 2005
    Messages:
    817
    Would he still see a spark at the points with an MSD box?
    Since the current carrying load is handled by the box and the points are only a trigger I wouldn't think there's enough current at the points to spark.
    I would still remove the points and clean off the contacts just to eliminate that as an issue though.
     
  7. Mar 14, 2014
    timgr

    timgr Jeepin' Nerd 2020 Sponsor 2019 Sponsor

    Medford Mass USA
    Joined:
    Aug 10, 2003
    Messages:
    20,581
    Depends on which spark you are talking about. Opening and closing the points should generate a spark at the coil or spark plug, but no arcing at the points.

    The MSD should not be picky about what kind of switch it needs to make a spark when set up for a Kettering trigger (points). You should be able to discard the condensor entirely - it's there mostly to protect the points from excessive arcing. Indeed, you should be able to simply ground the lead to the distributor and make the coil spark. IIRC this is the "MSD Test" that the OP refers to.
     
  8. Mar 14, 2014
    Walt Couch

    Walt Couch sidehill Cordele, Ga. 2020 Sponsor 2019 Sponsor

    cordele, Ga.
    Joined:
    Mar 29, 2007
    Messages:
    5,467
    Be sure you have two wires on the positive coil lead and that the positive coil lead is hot during crank mode.
     
  9. Mar 16, 2014
    74Cjake5

    74Cjake5 Member

    louisville colorado
    Joined:
    May 30, 2011
    Messages:
    102
    So I went ahead and got a net point set because on further inspection I noticed some deep burn spots (I haven't changed them since I owned the jeep) The next question is what to gap them to? Should I gap them as if there were no msd module, or is there a different gap size because they are triggering the msd?
     
  10. Mar 16, 2014
    Danefraz

    Danefraz Well-Known Member 2019 Sponsor

    Chico CA
    Joined:
    Aug 11, 2012
    Messages:
    1,968
    Interesting question. Gramps used to use a matchbook cover. I have a feeler gauge. TSM says gap on the 4 is 0.020" and 0.016" on the v6.

    Edit... No info in my book on the later 304.

    Sent from my iPad using Tapatalk
     
  11. Mar 16, 2014
    timgr

    timgr Jeepin' Nerd 2020 Sponsor 2019 Sponsor

    Medford Mass USA
    Joined:
    Aug 10, 2003
    Messages:
    20,581
    It probably does not matter much, considering how the MSD uses the points.

    However, I would assemble the points and condensor to factory specs, usign a dwell meter. Then if the MSD conks out, you are ready to use the points ignition as a backup. Easy on a Delco distributor, if you own a dwell meter.
     
  12. Mar 17, 2014
    jeepcj

    jeepcj Member

    cincy, Ohio
    Joined:
    Aug 23, 2009
    Messages:
    601
    " Gramps used to use a matchbook cover."
    A older friend of mine set my point gap on my jeep this way years ago. It worked
     
  13. Mar 17, 2014
    PeteL

    PeteL Member 2020 Sponsor 2019 Sponsor

    Hills of NH
    Joined:
    Aug 3, 2003
    Messages:
    6,701

    It does work. And don't call me Gramps.
     
  14. Mar 17, 2014
    74Cjake5

    74Cjake5 Member

    louisville colorado
    Joined:
    May 30, 2011
    Messages:
    102
    New points gapped to .017 jeep is running like a champ... now on to the transfer case...
     
  15. Mar 19, 2014
    Corveeper

    Corveeper Member

    Chanute, Kansas
    Joined:
    Jul 29, 2005
    Messages:
    817
    That’s a very good point. My Mallory Hyfire came with a bypass plug so that if the box ever “conks out” it can be unplugged, the bypass plugged in and the distributor then acts as it would without a box. That’s also why I kept my ballast resistor in line, in case I ever need to use the bypass plug.
     

Share This Page

New Posts