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90 yj 4.2 no spark

Discussion in 'Wrangler YJ (1986-1995)' started by Lineman1, Jun 10, 2017.

  1. Jun 10, 2017 at 8:44 PM
    #1
    Lineman1

    #1
    Lineman1 [OP] 1990 yj

    Joined:
    May 7, 2017
    Member:
    #1441
    Messages:
    13
    Gender:
    Male
    Sandy oregon
    Vehicle:
    1990 yj
    rear locker,garage fabricated rollbar, tube fenders,skid plates and rear bumper
    I have a nuttered yj that ran great for 10 years.It died while driving.Has voltage to coil 5.8v in run 10.6v in start. Pulled cap,rotor turns, replaced module (waste of $$)still nothing. I swapped the coil into another rig it fired right up.
    No spark at plugs,no spark to coil wire at cap.It sparks briefly when the key is let off start mode.
    Any help appreciated.
    I plan to do the HEI conversion but would like to resolve this issue first so I can address any issues with the swap on their own.
     
    Lineman1, Jun 10, 2017
    #1
  2. Jun 11, 2017 at 5:18 AM
    #2
    OFFGRID

    #2
    OFFGRID Well-Known Member

    Joined:
    Oct 3, 2016
    Member:
    #317
    Messages:
    2,018
    Gender:
    Male
    First Name:
    Peter
    Houston
    Vehicle:
    1979 Jeep CJ7, 258, TH350, NP208
    Howell fuel injection, header, HEI distributor, TH350, NP208, SOA lift with YJ springs in the front & GW springs in the Rear. AMC20 with G2 1 piece chromos trussed, Dana 30 with G2 chromos and 760x ujoints and MM Stainless Hubs, Geared 4.56. Tom Woods shafts, Metal cloaks, Caged, 37" Toyo MTs.
    If I had to guess I would say it is the electronics in the distributor. Get rid of the ignition module and coil, and do the HEI conversion with the integrated coil and all of that 5.8/10.6volts won't matter anymore. All you'll need is 12v
     
    OFFGRID, Jun 11, 2017
    #2
  3. Jun 11, 2017 at 8:31 AM
    #3
    Lineman1

    #3
    Lineman1 [OP] 1990 yj

    Joined:
    May 7, 2017
    Member:
    #1441
    Messages:
    13
    Gender:
    Male
    Sandy oregon
    Vehicle:
    1990 yj
    rear locker,garage fabricated rollbar, tube fenders,skid plates and rear bumper
    Yes I may have to just convert,pulled my dizzy this morning found the wire harness was very worn insulation was cracked and wire exposed where it passes through the housing. I have read the posts by Izzak JTHM71 and searched others now time to research the suppliers.
    I do look forward to cleaning up the wiring harness and simplifying things.
     
    Lineman1, Jun 11, 2017
    #3
  4. Sep 9, 2017 at 8:49 AM
    #4
    Lineman1

    #4
    Lineman1 [OP] 1990 yj

    Joined:
    May 7, 2017
    Member:
    #1441
    Messages:
    13
    Gender:
    Male
    Sandy oregon
    Vehicle:
    1990 yj
    rear locker,garage fabricated rollbar, tube fenders,skid plates and rear bumper
    Problem never resolved ,Received my HEI conversion kit from 4wd parts 120.00 today and now installing.Hope this is a fix will let you know shortly.
     
    Lineman1, Sep 9, 2017
    #4
    JKBob 25 likes this.
  5. Sep 9, 2017 at 9:53 AM
    #5
    aggrex

    #5
    aggrex Well-Known Member

    Joined:
    Sep 12, 2016
    Member:
    #203
    Messages:
    4,840
    DE
    Vehicle:
    Backcountry '16
    Tuffy>AEV>TTO>JW>STech>EVOcage>MagnaFlow>SpiderTrax>RockHard>TF>SpringTail>67design>Bolt>GPCA>Curt>
    At the minimum it removes a variable. Sub'd for the positive outcome
     
    aggrex, Sep 9, 2017
    #5
    JKBob 25 likes this.
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