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See if you can figure this one out... **PROBLEM SOLVED**

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by thatK30guy, Sep 20, 2003.

  1. thatK30guy

    thatK30guy 1 ton status Premium Member

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    Update 9/24/03: Got the problem fixed today and now the truck has its power back and an even smoother idle as well as running engine.
    Turns out number 1 & 3 plug wires were burned thru the boot as a result of them touching the damn headers. Got 2 new wires and the power came back.
    This is not the first time I've had trouble with the plug wires resting on headers. I've gone thru like 5 sets of wires and nothing seems to work. Right now I've got those Kevlar boots covering the plug boot and they seem to be working good. My next solution to eliminating the burning boots on wires is to switch from straight boots to 90 degree so they will not sit on the headers.
    Anybody else running 90 degree boots on BBC's? /forums/images/graemlins/confused.gif



    The 454 in my K30 runs good and smooth. Idles good and strong. But when I shift into gear (automatic), and start to acclerate, there is absolutely NO power at all. The motor becomes sluggish and backfires slightly. I tried WOT and it would not accelerate like it should. While on the highway, I shifted to nuetral and revved it and the BBC was smooth with no shakes or anything. Shift back to drive and the loss of power came back.
    I've checked the transmission and the fluid is clean and good. It still shifts good hard and crisp. But while doing WOT, 3rd gear did not kick in until I got up to around 60 mph.

    Sounds like the vacuum modulator is acting up? Or something vacuum-ralated with the th400? Any other ideas? /forums/images/graemlins/confused.gif
     
  2. rick88blaze

    rick88blaze 1/2 ton status

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    Re: See if you can figure this one out...

    check all your vaccuum lines. my dad had a chevy camper with a 400 in it that did the same thing. he changed a $3 check valve, and it fixed it.
     
  3. BowtieBlazer

    BowtieBlazer 1/2 ton status

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    Re: See if you can figure this one out...

    WES:

    Definately sounds transmission related, check the modulator, and next the TQ-convertor....after building a very strong stroker motor we had the same results and were disappointed in the engine, turned out to be the tranny, the engine is one hot sucker
     
  4. muddysub

    muddysub 1 ton suburban status Staff Member Moderator GMOTM Winner

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    Re: See if you can figure this one out...

    definetly vacuum related, try the modulator first.
     
  5. txtough

    txtough Registered Member

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    Re: See if you can figure this one out...

    If your running convertors then don't forget to check for back pressure. The effects are very similar to your problems and are often hard to diag. If all else fails try loosing and dropping your down pipes.
     
  6. FWP

    FWP CRS

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    Re: See if you can figure this one out...

    Had a similar problem on my K10, power -wise. Turned out to be the plug wires. Bought a cheap set from the local parts chain, which solved it. Took them back, and warrantied my original set of good wires (which lasted 5 years BTW). HTH....
     
  7. POWERMAD

    POWERMAD 1/2 ton status

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    Re: See if you can figure this one out...

    That just about sounds like the advance is gummed up.
    Smooth at an idle and so forth but under a load loss of power and backfiring.
    A timing light will eliminate that possibility.
    Or the coil could be ready to take a dump on ya.
    What you have described sounds like ignition and/or timing issues.
    Awhile ago my 73 had that little copper button under the coil burn out. It acted just about the same way.
    Idled good but ran like crap under a load. Spitting and sputtering and fell on it's face when the loud pedal was nailed.
    It burned out 2 of those before the coil went out.
     
  8. thatK30guy

    thatK30guy 1 ton status Premium Member

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    Re: See if you can figure this one out...

    [ QUOTE ]
    That just about sounds like the advance is gummed up.
    Smooth at an idle and so forth but under a load loss of power and backfiring.
    A timing light will eliminate that possibility.
    Or the coil could be ready to take a dump on ya.
    What you have described sounds like ignition and/or timing issues.
    Awhile ago my 73 had that little copper button under the coil burn out. It acted just about the same way.
    Idled good but ran like crap under a load. Spitting and sputtering and fell on it's face when the loud pedal was nailed.
    It burned out 2 of those before the coil went out.



    [/ QUOTE ]

    This is exactly what my dad was telling me over the weekend. Was asking how the coil was looking but I haven't had a chance to pull off the cap yet. Will be trying to mess with it Tuesday hopefully. /forums/images/graemlins/thumb.gif
     
  9. thatK30guy

    thatK30guy 1 ton status Premium Member

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    Problem solved. Go back to the top post and read about it. /forums/images/graemlins/thumb.gif
     
  10. KRAZIE87K5

    KRAZIE87K5 1/2 ton status

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    [ QUOTE ]
    Anybody else running 90 degree boots on BBC's? /forums/images/graemlins/confused.gif


    [/ QUOTE ]

    Aren't you supposed to run 45* boots on a BBC Westy? Thats what I always had on mine... regardless headers are BRUTAL on wires that aren't made for HI-TEMPS. I bought a set of Taylor wires for like $70 than ran well for an entire year... /forums/images/graemlins/rolleyes.gif

    -Dan
     
  11. FWP

    FWP CRS

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    Plug wires....

    "A blind squirrel gets an acorn once in awhile" /forums/images/graemlins/laugh.gif
     
  12. thatK30guy

    thatK30guy 1 ton status Premium Member

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    The Accel wires I used to run were straight boot, but called "vari-angle" since you could bend the boot to the desired angle you needed to clear the headers. I tried 3 sets of those and still burned thru them. /forums/images/graemlins/tongue.gif /forums/images/graemlins/angryfire.gif These "vari-angles" where simply boots you could bend to any angle you needed but they still didn't work for me. Then I found out about the Kevlar boot covers and installed them. Worked like a charm but still the heat can transfer thru them and still heat up the wires. Gotta look for thhose stock factory thin steel wire separator-thingies that bolt to the exhaust manifolds found on stock BBC's.
     
  13. KRAZIE87K5

    KRAZIE87K5 1/2 ton status

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    2 notes - #1. Accel wires SUCK in heat... known fact. #2. Accel wires have a LIFETIME WARRANTY! Hope you didn't pay for three seperate sets! /forums/images/graemlins/eek.gif

    -Dan
     
  14. 84_Chevy_K10

    84_Chevy_K10 Banned

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    I had a single bad plug wire that took me forever to find once. Didn't miss at all unless you really got on it. One day I was reaching down by the side of the motor when it was running and it bit me...found that damn thing quickly.
     

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