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Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by jimmyjack, May 23, 2000.

  1. jimmyjack

    jimmyjack 1/2 ton status

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    I have just poured about 1300.00 into my 83 BLAZER. Had some tranny problems and decided to spend some serious dough on rebuilding it all.
    The problem is I have an engine miss. I think its a valve or even a bad lobe on the cam. The compression runs about 150lbs on all 8 but i haven't done a leakdown test. Anyway do you think I should get the heads rebuilt or save the dough and get the whole engine reworked? Its only got 30,000 on it and it runs really strong except for the miss. It's already .30 over and I have no idea what the cylinders are like. Anyway it's a daily driver and offroading hasn't suffered much so I can wait. I'm very impressionable and your thoughts could sway my decision (hint hint wink wink)
    creepin and crawlin
    Jim
     
  2. James90

    James90 1/2 ton status

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    I would say new heads and maybe a hi-pro cam.

    But I really dont know jack![​IMG]

    If I were you I would find out what is worng and fix it if thr miss is the only porb at leae I thank that is what I would do.[​IMG]

    [​IMG]Go prepared
    </font color=red>90 k5 soon to be big, bad, and mean
     
  3. Casey 86K5

    Casey 86K5 1/2 ton status

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    you can check for a burnt valve by using a vacuum gauge, every time the burnt valve opens, the vacuum reading will drop. be sure to check the obvious, bad plug wire, spark plug, etc
     
  4. Russell Keys

    Russell Keys 1/2 ton status

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    The shade tree in me says to pull the valve covers and start it up. This would definately tell you if you have a flat lobe on the cam. Also check for burnt or cracked plug wires. Pull the cap and check it, maybe take the module to be tested(they can still run but be bad)if this applies to you. Maybe pull the plugs and see which are fouled or not firing. If it runs rough it could be a vacuum leak or carb needs adj. I didn't pay attention to what year you have so some of this might not even help. Good luck,Russell
     
  5. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Is the miss at idle or at speed? If it's at idle you may have a EGR stuck open. Ifi it's at speed the EGR ports may be plugged on one side. My 79 would idle perfect but get a "Miss" at about 1700 rpm. I Pulled the intake to do head gaskets and found the EGR port for one side of the engine was blocked so the other side was getting the full dose. The port for the EGR comes up in the Plenum devider directly under the carb.

    Diging it in the dirt with my K5's
    Grim-Reaper
     
  6. MudFrog

    MudFrog 1/2 ton status

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    If it's only got 30,000 on it, you might as well just fix the problem instead of saving for a differen't engine. Unless you wanted to upgrade to say...hmmmmm.....a 502 or something :-)
    Let me guess....Yea Right...It'd be sweet as hell though
     
  7. Mudzer

    Mudzer 1/2 ton status Author

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    What carburator do you have? Engine miss is not always valvetrain or ignition related. I poorly operating carb will cause a bad miss. Sounds like with only 30k miles on it, the motor should be fine, check the other things like carb adjustment or ignition.

    <font color=red>Mudzer</font color=red>
    1978/91 K5 Blazer
     
  8. jimmyjack

    jimmyjack 1/2 ton status

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    I've been chasing this for awhile and I've replaced all the wires,cap and rotor, had the carb worked on. The #8 plug gets pretty fouled up on a regular basis. I'm not realy sure I want to get that involved in it. I might just find a junk motor and build it up while this one rattles on for another year or so. I've still got to install my tranny, I'm picking it up today and I'll be busy tonight. If you live near Tucson and your dog starts howling, thats me screaming profanities at the top of my lungs!
    creepin and crawlin
    Jim
     
  9. BluThndr71JMMY

    BluThndr71JMMY 1/2 ton status

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    Hey Buddy,
    I live in Tucson (well, speed trap city --Oro Valley) with a similar gripe: I've got a '98 350 box motor [old style] in my '71 GMC Jimmy with less than 12,000 miles on this engine. When I put an HEI distributor on it, it took all kinds of hell to stabilize. I rebuilt the carb; r&r'ed the counterweights and springs,cap, rotor, module,condenser,coil, pickup-coil,plug wires with fibreglass boots. I added a big ground strap. I even changed the oil. It gets a little better with each step, but it still has a hard time on acceleration. It idles smooth and strong.I've been trying to get on a scope, but don't seem to find a time that's convenient for some mechanics. A friend thinks I need a valve adjust, but the engine's awful young --11,800 -- for that. But I'm not the expert. Maybe it's the #@%$-ing gas they're palming off on us here?!
     
  10. Executioner

    Executioner 1/2 ton status

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    Hay, I am in Tucson also, lets try to meet/get together this long weekend. I am off fri-mon
    If you can give he a little more history on your problem I give it some thought.
    P.S. should be 107-109 this Sunday
     
  11. jimmyjack

    jimmyjack 1/2 ton status

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    Only 109 on sunday? I don't work on my truck unless its at least 115. I love this heat don't you? I live near 22nd and Kolb if you want to try and hook up. I'll probly put my tranny tomorrow and get it rolling again. Its been 3 weeks since I even had the motor running. The miss is kinda funny. I can go out start the motor and hear it plain as day, another time it'll just chug right along but I notice when i stomp it, it feels like the valves are floating. I hope its the carb. I tried to put an edelbrock on but the egr is the size of a Denny's platter and i wasnt going to put two inches worth of adapters on to make it fit.
    E mail me and maybe we can hit Redington or something. I've got two friends in the Rough Riders, Derek and Virgil Doran, and another guy ummmmm Bob Lozen i think, he has a jeep with a pepto bismol pink stripe on it.
    creepin and crawlin
    Jim
     
  12. getsome

    getsome 1/2 ton status

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    Just a thought. When I put on my new Edelbrock carb I had the the same problem with the EGR running into the electric choke. I went to get a beer and came back out to find that my EGR called my chisel a slut then it was a slug fest from their on out. The chisel won by cutting me EGR's head off. I didn't want to have a big vacuume leak so I put the EGR back on and filled in the holes with silacone and what do you know my new carb fit! The moral of the story is: always lock up your tools.

    Getsome
     
  13. Espen88k5

    Espen88k5 1/2 ton status

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    Need stitches after that one!!! You guys really make my day. Sometimes during the night I'l brake in to a giggle and my wife will ask what's so funny.
    She claims I'm spending to much time on CK5.

    <font color=blue>Espen88k5</font color=blue>
     
  14. Executioner

    Executioner 1/2 ton status

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    Sounds good ! I am a member of TRR as well. Look for private message.
     
  15. jimmyjack

    jimmyjack 1/2 ton status

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    i like the analogy. my wifes car called my truck a sissy and it got so upset that the tranny blew up.
     
  16. SnakeEyes

    SnakeEyes Registered Member

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    Is the #6 hole the problem?? Sounds like a burnt or partially burnt valve to me. Try this. Disable the coil so it won’t start when you crank. Crank it over and listen to see if the engine speeds up through the cranking cycle at any point. If the mill is healthy then the strain against the starter will be constant. If you have a hole somewhere, sounds like #6, the starter will speed up when you go past the hole.
    To locate it more precisely, fill each cylinder in turn with about 180psig of air AFTER making sure that the piston you are working on is at BDC, and then listen to see where the air is leaking from the cylinder. Carb, exhaust , or (you’ll love this part) water jacket. Take off the radiator cap and look for bubbles!
     

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