combustion problems - HELP

Discussion in '1974 - 1978 Mustang II Talk & Tech' started by cobra_2_76, Jul 25, 2004.


  1. Wart

    Wart I'm Mad as HELL and I'M not Gonna Take it ANYMORE! Founding Member

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    That could have turned the car into a paint shaker but wouldn't have kept it from running.
     
    #21
  2. cobraii351

    cobraii351 Founding Member

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    I popped a dist. gear roll pin a few years back. I couldn't figure out what the problem was as I just drove 45 miles!! Turned a corner and pop..... BANG! I it sounded like a gun going off. I parked and ****ed with it a while and found nothing. Every once and again it would go off like a gun. Load the exhaust with raw gas and hit the fire while an exhaust valve is open and look out! I guess my oil pressure fuel pump shut-off paid for itself. I wasn't getting gas except when I turned the key.
    I got a tow and scratched my head for a bit. I had pulled the cap and hit the key and the rotor moved so I forgot about it and moved on to other things. Later a friend said to recheck it and I pulled the cap and this time grabed the rotor and gave it a good twist! A $.15 roll pin cost me a 25$ tow. Don't underestimate the power of a very tiny part binging things to a stand still.

    Good luck finding the cause. I hope it's an easy fix for you.

    Tim
     
    #22
  3. cobra_2_76

    cobra_2_76 Founding Member

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    Wasn't the pin. Pulled the distributor last night, gear was tight. Decided the best way to check to see if the pin was sheared to was to try and drive it out. Three taps and out the pin popped intact :damnit: , hole real nice adn round. Put it back together, so tonight I tear the front of the engine down....weeeeeee.

    Dave
     
    #23
  4. Wart

    Wart I'm Mad as HELL and I'M not Gonna Take it ANYMORE! Founding Member

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    Your sure the reluctor is still tight on the shaft?
     
    #24
  5. cobra_2_76

    cobra_2_76 Founding Member

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    99% sure yes, there's always that lingering doubt/possibility something was overlooked.

    I'm tearing down the front end tonight and at a minimum I'll at least be able to eliminate a variable. You did remind me that the alignment pin wasn't as tight as I expected and from the perspective of FINALLY identifying the problem, hope it has moved and caused the problem. At least I can then fix it and again start terrorizing the neighborhood!

    And our local Buckeye Mustang Club has rented NRP and I was really hoping of getting out there and seeing what it would do.
     
    #25
  6. cobra_2_76

    cobra_2_76 Founding Member

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    :bang: Bad news....nothing wrong in timing chain area. Cam pin intack and properly aligned. AAAAAAAAAAAAAAAAAAAAAAAAAHHHHHHHHHHHHHHHHHHHH

    I guess I'll put it back together, re-check all parts of the distributor, lube it up. Recheck MSD box is working, re-align the distributor to #1, and re-check the carb.

    Start over with evaluation too.

    Wart: correct my logic if I'm wrong. If the weights on the relulctor stuck then the whole distributor would be advanced requiring the initial advance to be retarded to compensate before it would run. Opposite of what I thought I saw?



    Thanks everyone for all the ideas.
    Dave
     
    #26
  7. Wart

    Wart I'm Mad as HELL and I'M not Gonna Take it ANYMORE! Founding Member

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    Crank gear and key intact?



    Well, yeah, theres 20 - 30 degrees of mechanical advance in the distributor, if it got jammed it could cause problems, I thought the distributor was A-1.
     
    #27
  8. cobra_2_76

    cobra_2_76 Founding Member

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    Key way fine....I even took a hack saw to it...now just cut a small groove between both sides of the harmonic balancer halves to make sure it's not moving.

    If the 30 degrees of advance got stuck and it would only run with 30 degrees of initial advance, then moving it to 10 degrees should make it run better not worse? I'm not positive on the logic, is my sense right or wrong??? Maybe was the key to the problem.

    Dave
     
    #28
  9. 77sleeper

    77sleeper GO BUCS! Founding Member

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    with that much advance it would run way hot though, wouldn't it
     
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  10. zwhitr

    zwhitr Founding Member

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    you mentioned balancer being like 30 degrees off I had the same problem with mine on another thread.

    use the positive stop method and find TDC and bump it up to your current balancer bet you will find there is nothing wrong other than the marks being in the wrong place.

    IE... not a II specific part .

    your marks should be roughly in the 10:00 position when TDC

    good luck I'll search for the thread It might be you situation if you balancer is not stock...
     
    #30
  11. Dano78

    Dano78 Founding Member

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    Seems as if you've covered most the stuff! I've had the dist. gear shear off before. Was a real head scratcher for a while. Also had a cam chew away 1/2 the dist. gear and jump time. Came to find out the damn cam bolt had loosened up and backed out enough to cause the cam to "walk" but still work the eccentric! Took a couple of days to figure that one out.

    Think you might have problems with the centrifugal weights/springs inside the dist.? Still a possibility of an ittermittent short in the MSD box. Might want to bypass the MSD system and see if that corrects it. Usually I stuff a points dist. in the car for this, real simple to set up the points without butchering your current wiring for the testing purposes. That, and they are cheap, if you don't have one.

    I've also seen Hi-pressure oil pumps, when revved, over pressure lifters causing the valves to hang open. But I don't think yours is in this area.... at least I don't think it'd alter the timing that greatly.
     
    #31
  12. kcobra302

    kcobra302 Founding Member

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    about a year ago i replaced my distributor with a remaned unit.
    the car was running pretty good then the performance started to decline. this spring i check the msd box, coil, plugs, wires couldn't really place my finger on the problem. then i started to have the same problems you are having. swapped the carb out, tried different chokes, went thru the dstributor top to bottom, advance kit, everything.

    so after watching this thread i decided to barrow and msd distributer from a friend of mine. no vacuum advance, just a straight up distributor.

    car runs great.
     
    #32
  13. cobra_2_76

    cobra_2_76 Founding Member

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    Short answer it runs!!! Seems the coil was not dead,
    worked but just barely enough to hide its
    problems....here's what transpired.

    Well went back to the drawing board and started over
    with the spark. Re-checked the magnetic trigger on
    the box and got a good spark with a plug in the coil
    wire.

    Next decided to check the wires from the MSD box to
    the distributor. Stuck two tabs into the female side
    of the Duraspark distributor connection and used a
    screwdriver to make the trigger jump. Again fantastic
    spark with a plug in the coil wire.

    Next put the coil wire on the cap, aligned the rotor
    with a plug terminal, pulled that wire off at the head
    and installed a spare plug. Then ran the screwdriver
    over the terminals again to trigger the plug.....hit
    six times THEN it started discharging in the MSD box
    not at the plug. OOOOOO, shades of a bad box?

    Tried several times with same results. Re-checked
    cap, no cracks.

    Friday morning called MSD and discussed findings. Of
    course electricity finds the closest ground, so
    concensus was box was ok. Said to check coil. Now
    the instructions say if the ignition FAILS to replace
    the coil and if it still doesn't work return the box
    for service. They gave me the ohm spec's for the
    primary and secondary windings.

    My ohm meter on my Craftsman diagnostic box failed so
    Friday I take an eary lunch to Radio Shack and they
    don't carry one in those ranges, darn. Off to my
    favorite parts store and get one there. (Should know
    better and stay with a sure thing.)

    Take off early from work, (one of the few benefits of
    being salaried!) Get home and check the ohms.

    Supposed to be .7 for primary and 4.7K for secondary.
    The coil registers 1.2 primary and 4.3k secondary

    Hummmm, call MSD back and they say the coil is bad.

    OK, off to Summit, three and a half hours later return
    with the coil. Ohms match, install and still won't
    run. ****.

    This morning go back out and recheck - notice no fuel
    in carb. Hummm, I know I re-tightened the cam
    eccentric bolt, but no fuel. Try some gas in the carb
    anyway, doesn't run. Oh well, I'll get back to it
    when I get the eccentric tightened. Get started
    tearing the power steering off AGAIN, when I notice my
    vice grips hanging under the car. Darn forgot to hook
    up the fuel lines to the pump. Hooked it up, turned
    over the car to fill the bowls and IT STARTS!!!!

    Seems the thing was slowly failing....who would have
    guessed. Because it was not generating a strong enough
    charge it wouldn't jump the gap in the distributor and
    grounded in the MSD box. I guess if I had followed
    the MSD instructions I would have saved a lot of
    frustration, but darn it was still generating a spark.


    OH well it runs great and I'm out of my gloomy
    cloud!!!! Summer may be good afterall!!
     
    #33
  14. Blue Thunder

    Blue Thunder Active Member

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    Cool that you found the trouble.
    In the future, to check for coil issues, pull the coil wire out of the socket and rest it on top so there's a small gap between the wire terminal and the coil terminal. Run it. The gap will increase resistance and force the coil to put out more current to bridge the gap. If the car runs better when you add the gap, you know the coil is bad. (Don't leave it running for a long period with the wire loose or the coil might eventually overheat and explode like a grenade)
     
    #34

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