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Engine miss on startup

Discussion in 'Wrangler YJ (1986-1995)' started by Jeepjoc, Aug 18, 2017.

  1. Aug 18, 2017 at 7:31 PM
    #1
    Jeepjoc

    Jeepjoc [OP] Well-Known Member

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    Dennis
    Albertville, AL
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    1995 YJ Wrangler Rio Grande
    As I posted earlier in a separate thread, I was havin' a problem with my Jeep cutting out and backfiring as I was driving along. I changed the rotor, dist. cap, HT leads, plugs, ignition coil, air filter and fuel filter and crankshaft position sensor. All that seemed to have cured the problem and the Jeep ran much better than it had before. Now I developed a new problem and I'm hoping the members here might be able to provide a clue.

    The new problem is that on startup, there is a very obvious engine miss, like only three cylinders with the check engine light illuminated. After a short drive I can make the check engine light go out by turning the engine off then back on and the miss goes away. Kinda like rebooting the system.

    Any ideas???

    Cheers - Jeepjoc
     
  2. Aug 18, 2017 at 7:55 PM
    #2
    chris4x4

    chris4x4 With sufficient thrust, pigs fly just fine Moderator

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    Hows the wiring?
     
  3. Aug 18, 2017 at 8:01 PM
    #3
    Jeepjoc

    Jeepjoc [OP] Well-Known Member

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    Dennis
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    Gotta admit that I really haven't had a look under the hood. Plan to get into it tomorrow and hoping there will be something obvious. I'm satisfied that the complete ignition system is good as I replaced about everything there is to replace.

    Cheers - Jeepjoc
     
  4. Aug 18, 2017 at 10:28 PM
    #4
    OFFGRID

    OFFGRID Well-Known Member

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    Houston
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    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.
    Camshaft sensor maybe?
     
  5. Aug 19, 2017 at 8:06 AM
    #5
    Jeepjoc

    Jeepjoc [OP] Well-Known Member

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    It's possible that the problem is the camshaft position sensor but to me the symptoms don't match unless I'm missing (pun intended) something.

    Cheers - Jeepjoc
     
  6. Aug 19, 2017 at 10:21 AM
    #6
    Jeepjoc

    Jeepjoc [OP] Well-Known Member

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    Dennis
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    I'm also suspecting a possible fuel contamination with water problem but unsure if the displayed symptoms support that scenario. A couple of weeks ago, I changed out the fuel filter and while doing this task, I put a pan under to catch any fuel spill as I hate it when fuel runs down my arm. Before I emptied that pan, I noticed what appeared to be small bubbles at the bottom of the pan. Several of them. I'm pretty sure they were water as water is heavier that fuel and will separate. How would you remove any collected water from the fuel? Would "Heat" do the job.

    Cheers - Jeepjoc
     
  7. Aug 19, 2017 at 10:36 AM
    #7
    chris4x4

    chris4x4 With sufficient thrust, pigs fly just fine Moderator

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    Drain the tank completely and re fill.
     
    aggrex likes this.
  8. Aug 19, 2017 at 12:19 PM
    #8
    aggrex

    aggrex Well-Known Member

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    DE
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    Tuffy>AEV>TTO>JW>STech>EVOcage>MagnaFlow>SpiderTrax>RockHard>TF>SpringTail>67design>Bolt>GPCA>Curt>
    Complete drain of tank as described by Chris4x4 and no heat
     
    chris4x4 likes this.
  9. Aug 19, 2017 at 3:45 PM
    #9
    Jeepjoc

    Jeepjoc [OP] Well-Known Member

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    I believe that I found the problem. Upon examination under the hood, I found one wiring harness connector loose and a couple of vacuum lines that were not well attached. Corrected those things and now everything seems to be good. Keeping fingers crossed. Might still have some water in the fuel which is now on my list to take care of.

    Cheers - Jeepjoc
     
    chris4x4 likes this.
  10. Aug 19, 2017 at 5:07 PM
    #10
    aggrex

    aggrex Well-Known Member

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    Good that you found the wiring + vacuum lines issues. Run the tank pretty low and fill up with fresh 89 fuel and/or try some drygas additive
     
    JKBob 25 likes this.
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