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Suggestion for a very rough running motor???

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by midnight473, Jun 9, 2003.

  1. midnight473

    midnight473 Registered Member

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    I have an 88 K5 that is stock. The engine started running rough and wouldn't idle. Thought it was a timing issue. Set it, reset it and set it again, didn't help. It had some valve seal leaks (187,000 miles) so I put in a new rebuilt stock 350, however it was bored .30 over. I have checked all vacuum lines visually as well as with starting fluid spray while running. It will run with some throttle roughly, but no idle. Timing is right, does anyone have any suggestions? It's killing me to spend $1100.00 on a motor and still not have a truck that runs. If there is something I am missing or more information needed, let me know and I will describe as best I can. Thanks!
     
  2. mud390

    mud390 1/2 ton status

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    Have you tried cleaning the carb? What kinda shape is your ignition system in? Are the plugs fouling out?

    Kris
     
  3. doctor4x4

    doctor4x4 1/2 ton status

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    mabe ya have a weak spark even if ya get a spark its not ( hot enough ) just an idea
    but because its a 1988 ya got the tbi set up right ??
    well also check your computer for the problem codes
    could be lots of things incorrect air - fuel mixture etc bad o2 sensor etc etc etc
    hope it helps and best of luck 2 ya
    Randy
     
  4. Shaggy

    Shaggy 3/4 ton status

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    <font color="green"> THe most obvious problem to me would be that the distributor is in 180 out. </font>
     
  5. midnight473

    midnight473 Registered Member

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    yes, it is a TBI setup. Sensors were going to be my next step forward. I can't believe the distributor would be 180 out do to the motor being shipped TDC and setting the distributor with #1 at roughly the 5 o'clock position. I suppose it's possible, but I don't know if likely.

    I don't have access to a computer to check the codes, although I suppose for the headaches in the future, investing would be a wise decision.

    Thanks for the suggestions. I'll keep plugging at it.
     
  6. R72K5

    R72K5 Banned

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    187,000 miles on it, its getting tired, i cant say that id expect it to run like new anymore, i run across old 350 engines all the time that are so tired they wont ecvne move the truck hardly, i just junk them i dont even mess with them 4 bolt or not, got one in a 77 thats got a dead miss but no knocking and number eight spark plug hole threads are stripped bad, just am gonna scrap it, same with the 79 350 thats had intake and valve covers off for so long and is dirty in lifter gallery, engine turns by hand and had comperessiona nd all, probablyt would run, but its old and tired and pretty much done, can get a good running one cheaper than rebuilding, a local repair shop guy here thinks im crazy for junking tired 350 4 bolt engines that i have and claims it woulkdnt take over 150 to fix anything wrong with an old 350,
    im sorry but by the time lagor and parts are over it wil be several hundred dollars to fix heads and get gaskets only to end up throwing a rod or bearing which usally happens on old tired engine thats you redo heads on....

    just scrap them, and find a good one, even new heads are way better than any stock ones and are less expensive than stock rebuilds nowadays, its a whole new day than what it was like 30+ years ago, even 20 or even 10



    good luck /forums/images/graemlins/laugh.gif
     
  7. midnight473

    midnight473 Registered Member

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    I did scrap it, this is a newly rebuilt with 0 miles on it motor.
     
  8. slimlynn1

    slimlynn1 1/2 ton status

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    If your new engine has the same symptoms as your old one it sounds like it is an electronic problem or your TBI unit needs rebuilding or replacing. Holley makes a 670 CFM TBI unit that should bolt right up. I would also check your distributor and coil. I assume you put new wires on it when you put the new engine in. Good luck.
     
  9. daimok

    daimok Registered Member

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    egr valve can cause this , if its sticking open. easy to check , pull and use a screwdriver to push in the valve. if its sticking or sticks open , that would do it. I also like marvel mystery oil in the gas and oil to unstick piston rings
     
  10. midnight473

    midnight473 Registered Member

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    Yeah I put the Holley on as part of the new engine swap, that didn't have an effect. The EGR valve however, that is one that I haven't looked at for sticking. I will pop that off this evening or tomorrow and take a gander.

    Thanks all for your tips. /forums/images/graemlins/thinking.gif I knew this would be the place to get this functioning again, I just hope that I can.
     

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