When to replace distributor cap and rotor

Discussion in '80-Series Tech' started by Tool Pusher, Mar 30, 2008.

  1. Tool Pusher

    Tool Pusher

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    My '94 started having a stumble off idle. It idled fine and ran smooth at higher RPMs. But at low RPMs and off idle it stumbled. My first inclination was to check the spark plugs since I had never replaced them after I bought the vehicle over a year ago and did not know the repair history. It also seems logical since the stumble only happened under load at low RPMs when it was hardest to make a spark. When I pulled the first plug out the problem was apparant. The spark plug body was in good shape, and the color on the electrodes was good but the center electrode was worn way down and was rounded to such an extent that the gap was almost double what it should be. all the other plugs were similar. I put in new spark plugs and the stumble is gone. While doing the plugs I went through the rest of the ignition system. The plug wires tested OK with the longest wire at about 27K ohms when the spec. max. is 25K ohms. Do I replace the wires as a set or can I replace just the one that is out of spec? I tested the coil and it is in spec. on the high voltage side but a little out of spec. on the low voltage side. Might get a new one of those. My main question is on the distributor cap and rotor. The FSM does not give a spec. or time frame to replace them. The contacts on the cap look a little eaten away from the arc and so does the rotor contact, but I do not have a new one to compare it to. What is the recommendation of the list?

    Thanks, David Sword
     
  2. sseaman

    sseaman

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    i would replace the wires, plugs, distributor cap, and rotor, if it has been that long, it would be rare for someone to replace the distributor cap, and rotor, and not do the plugs at the same time



    OVER DUE
     
  3. whodat

    whodat

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  4. Tool Pusher

    Tool Pusher

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    That answered it.

    Thanks guys.

    David Sword
     
  5. Brian894X4

    Brian894X4

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    My OEM wires has the date of manufacture on them. I purchased new wires from C-dan only to find that the PO must have replaced them, because they have 2003 on the wires. So, if you have old wires, you'll at least know it, if they are OEM style.
     
  6. Tool Pusher

    Tool Pusher

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    Mine say 1995. Guess it is time for replacement. Vehicle has almost 160K miles so I would estimate the wires have over 140K miles on them. I would guess that the distibutor cap and rotor are the same age.

    David Sword
     
  7. Brian894X4

    Brian894X4

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    Good call...cheap insurance.

    Nice feature having the wires date stamped like that. New ones from C-dan last year are stamped 2007. Haven't put them on yet, since my 2003 ones aren't that old.

    If you have a '94 and the wires say 1995, they might be original. If not, makes you wonder why they put on new wires 1 or 2 years after the rig was built. That's pretty unusual. Maybe defective...and replaced under warrenty?
     
  8. sseaman

    sseaman

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    You arent talking about a huge expense for these parts either.
     

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