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454 Plug wires?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by option#9, Mar 6, 2003.

  1. option#9

    option#9 Registered Member

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    I just picked up a 76 K5 with a built 454 in it this weekend. I didn't buy it from whoever built it so I don't have much info on it. Anyway I was told it wouldn't start so I replaced the cap, wires, plugs and it fired right up. One of the wires was too close to the header and got a little hot and the truck wouldn't start anymore so I bought a new set. Put them on and it fired right up. I drove it home and started it two days in a row first try. On the third day it wouldn't start again. It sounds like it did before I replaced the wires. I can get it started but it won't run without half throttle and smokes quite a bit. It has an MSD ignition and coil (no HEI), could I be burning the cheap plug wires from the inside out?

    When I was driving it home it was hesitating quite a bit if you stepped on it under load.

    Is it possible the distributer is one tooth off?

    Any ideas?

    Great forum by the way.
     
  2. Blazer79

    Blazer79 1/2 ton status

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    Re: 454 Plug wires? (kinda long)

    If cables are only 3 days old, I don't think they are being roasted, unless they are some really cheap cables.

    If the dist were off by a tooth, it would have never started or at least hard to start, ping a lot and almost undriveable. I'd look into the carb mixture settings. Maybe the carb simply needs adjustment or a rebuild at most.

    Good luck. I have a 454 too. If you have any more questions, just ask.
     
  3. Langosta39

    Langosta39 1/2 ton status

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    Re: 454 Plug wires? (kinda long)

    I had a similar problem with my 454. I had an old set of wires (mismatched even!) and it ran great, after I pulled the motor and put it in my other truck it ran like crap, at first on 7 cyls, thought I smashed a wire putting it in, but then on like 5 cylinders! It ran so bad full throttle would barely hold 1000rpm. Needless to say after 10 minutes of that all the plugs were ruined from the FREAKIN RICH mixture. New plugs, cap, rotor, wires and it was back in action.

    I don't know what to tell you about your wires, but check the plugs and clean them up it they are dirty, and verify all your points stuff. I suppose the carb could be at fault, making it run too rich and ruining your plugs, but I don't know where to start on that.

    andy
     
  4. Greg72

    Greg72 "Might As Well..." Staff Member Super Moderator

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    Re: 454 Plug wires? (kinda long)

    The MSD ignitions have a requirement for the plug wires.....

    I forget all the details, but the resistance per foot is only supposed to be around 40 -50 ohms. That means on the longest wires you should be at no more than 150 ohms or so.


    The MSD will "mask" bad wires for a while by increasing the power to the wire. The effect will be to burn out the center button on the distributor cap (ask me how I know!)

    My suggestion is to verify that the wires you are buying are compatible with MSD-style ignitions....and then if you crimp the ends yourself.....check EACH one with an ohm-meter to be sure you're in spec.
     
  5. option#9

    option#9 Registered Member

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    It was the plug wires. Wierd huh? I took a look at the ones I had on there (belkins from Napa) and there was no physical sign of heat damage. I ordered a set of Taylor Spiro-Pro's and it started up first try. Nice wires by the way.

    Anybody ever heard of bad wires in 3 days? I'm hoping the Taylors will last me a little longer.

    Thanks for the suggestions. I do need to do some carb adjustments but I didn't think it was the root of the problem.
     
  6. captain chaos

    captain chaos 1/2 ton status

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    well if you are running header's, those cheap napa wires arn't gonna stand up to the heat. (unless you put a protective heat boot on the end).
    also where they the 90degree boot on the spark plug end?
    as far as i have seen with bbc with header's you need the straight long boot on the plug end.
    the msd 8.5's work real nice as you can also bend the boot end a little.

    dave
     

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