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Blazer Running Horrible and cutting off. Need some good Help

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Boss, Oct 18, 2001.

  1. Boss

    Boss 1/2 ton status Author

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    Hello,
    This question is for my brother. He drives an 88' S10 Blazer, 2.8L Engine (yes, wimpy) TBI. About 100,000 to 105,000 miles or so.
    He described these problems to me over the phone, so I actually haven't heard or seen the problem (he lives about 30 min away). I want to help him out, but not sure the prob. Ok, here's the description according to him.

    * Blazer starts making a violent type knocking sound in the front end when accelerating from like 15mph and up. When he lets off the gas, the knocking type sound goes away.

    * When he is slowing down, close to stopping, the front end of the truck starts to shake.

    * 40% of the time, when he is at a complete stop, he says the front end shakes violently, then cuts off.

    * When idling, the truck will idle smooth, then shake up front, then idle smooth, then shake again, etc.

    What could be causing this? He said he got a Complete tune up at about 90,000 miles or so. (paid about $200something)He got it professionally done, and says, the plugs and wires were changed, the fuel filter, pcv valve, etc, etc. He is NOT mechanically inclined at all. Knows little to nothing, except how to change his oil, and that's it. I will admit, I'm mechanically challenged when it comes to motor probs and stuff.
    I'm thinking he may need a new O2 sensor and maybe even new exhaust, something might be clogged in there??? I'm not sure what to tell him or where to begin to look when I check it out. Anyone have any ideas what could be causing this? I hope it aint the motor for his sake, b/c he is a extremely poor college kid with no $$ [​IMG] Any help, appreciated and thanks in advanced.



    Pic of my truck Before N' After
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  2. FWP

    FWP CRS

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    I'm not sure if this is the same problem, but I have seen automatic transmissions that lockup when they shouldn't, causing similar symptoms.

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  3. Boss

    Boss 1/2 ton status Author

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    You think a locked up tranny will cuase it to stall too? I'll tell him to check this tranny fluid and stuff. It still drives, so I'm not sure if his tranny locked up. Who knows, thanks for idea.


    Pic of my truck Before N' After
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  4. MUDNUTT

    MUDNUTT 1/2 ton status

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    without hearing it run this is just a guess but has the cat ever been changed. if its the original with that many miles it could be plugged.
    deck

    <font color=blue>DRIVE IT LIKE YOU STOLE IT[​IMG]
    <font color=red>PROUD TO BE AMERICAN[​IMG]
     
  5. Boss

    Boss 1/2 ton status Author

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    Mudnutt,
    I was actually thinking the same thing. It is the stock Cat and Muff, so that's might be it. I needed a 2nd opinion though, b/c I'm not sure. I haven't heard or seen the problem either, so this is all second hand to me too.

    Pic of my truck Before N' After
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  6. FWP

    FWP CRS

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    The lockup style Torque converter can lock the motor to the tranny, causing shuddering at stalling at idle, and all kinds of other wild stuff. Kinda like a manual tranny when the clutch isn't released fully. But, I'm just taking a guess on this. Good luck!

    <a target="_blank" href=http://coloradok5.com/gallery/75K5>http://coloradok5.com/gallery/75K5</a>
     
  7. Rebel88

    Rebel88 1/2 ton status

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    i have an s10 pickup that did the same thing but it was due to the fuel pump going bad...it was on sometimes and then it would cut off causing the truck to stutter and shudder then it would cut back in...sometimes the truck wouldnt start but if you hit the bottom of the tank it would...me and my pops changed mine but it was a pain in the ass because you have to drop the whole fuel tank to do it...the pickup and pump are built into the top like some blazers are...

    Later

    Have you driven OVER a Ford lately?
     
  8. MUDNUTT

    MUDNUTT 1/2 ton status

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    boss, any good muffler shop can check the cat. they drill a small hole in front of the cat and insert a guage then start it and measure the backpressure. if its plugged they'll know right away, the guage will pegg. as i said without hearing it run its just a guess, it may verywell be something one of the other members suggested
    deck

    <font color=blue>DRIVE IT LIKE YOU STOLE IT[​IMG]
    <font color=red>PROUD TO BE AMERICAN[​IMG]
     
  9. Boss

    Boss 1/2 ton status Author

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    FWP,

    If it is a Locked up torque Converter Problem, how does one solve something like that?
    He looked at the Tranny fluid and said it looked kinda burnt (brownish type color). He said the Tune up people "supposedly" changed the fluid and filter about 10K miles ago though. I'm starting to doubt they did now.

    Mud, thanks, I will tell him to get that checked out.

    Reb, yeah, changing In-tank style fuel pumps suck. I dropped the tank on my K5s plenty, so I know what that's all about!!
    Boss


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  10. 1986Blazer

    1986Blazer 1/2 ton status

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    Messed up tranny would not cause the knocking (pinging) while accellerating. I will bet my bottom dollar it is the timing belt - I think that engine is a belt not a chain. They usually need to be replaced at 75K so at 105K it is plenty old. It may have slipped two or three teeth and the timing is too far advanced. That would explain the knocking. It could also be, but unlikey unless he did some work himself, is that one or more of the sparkplug wires are in the wrong place. I did this by confusing the number 5 wire with another one. The damn engine shook like a 8.5 earthquake but it would run if I got the RPM up enough. Just my 2.5 cents

    <a target="_blank" href=http://www.geocities.com/keywestk5/KeyWestK5.html>http://www.geocities.com/keywestk5/KeyWestK5.html</a>
    So I says to him, I said, "get your own monkey."
    1986 K5, 350 GM Crate, 700R4, NP208
     
  11. Boss

    Boss 1/2 ton status Author

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    Thanks 86'. Haven't thought of that one. I'll try and look into it. I doubt it's the plug wires in the wrong place. This happened kinda of recenlty. At first the truck would just cut out everyonce in a while, but now it's shuddering and shaking violently and often. Thanks for all the suggestions. I will have my hands full when I look at this thing!! [​IMG]
    Boss

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  12. Danno

    Danno 1/2 ton status

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    GM 2.8L V6/60 engines do not use timing belts, they have chains.

    1984 K5 Blazer 4x4 Silverado
    6.2L diesel, 700R4, 3.42 gears, 31x10.5" tires
     
  13. Boss

    Boss 1/2 ton status Author

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    Hmm, well that scratches that out then, I guess(...(shows you how much I know about 2.8Ls [​IMG] [​IMG]



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  14. Stoopalini

    Stoopalini 1/2 ton status

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    Timing belt would definitely be a thing to check. Just bring a timing light and see where the marks line up.

    Another thing, totally shooting in the dark here, but how about a broken motor mount? If a motor mount is shot, and the motor is shaking like crazy, the knock sensor (TBI, right?) could be causing the timing to retard big time.

    He can check the motor mount with a frined. Just have one look at the engine while the other holds the brake and gives it gas in drive, and reverse also. See if the engine jumps around in the bay.

    Good luck man,

    Thomas.

    -- '84 1-Ton Blazer --
    When the goin' gets tough,
    the tough go 1-Ton [​IMG]
     
  15. Chris Demartini

    Chris Demartini 1/2 ton status

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    <font color=blue>You dont need to drill holes to check the cat. All you need is an infrared temp gun (not as expensive as you would think). If its warmer at the front of the cat than it is at the back, its clogged and causing excesive backpressure. I would also check the timing and ignition system
     
  16. Kyle89K5

    Kyle89K5 1/2 ton status

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    Jumped time? Never know, we just changed out a timing chain on one with less miles than that. The puter may be trying to compensate for an illtimed vehicle do to chain stretch.

    Kyle
    89K5
     
  17. FWP

    FWP CRS

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    Well, even though I may be wrong as to the actual problem, this may help for future situations. Usually things fail that are not repairable, but a rebuild, replacing all the worn out components, is the usual on an auto tranny. Yeah, sometimes it's the simple stuff, like kick down cable, vacuum modulator line, etc... well worth looking at first. If that doesnt't work, the pan can be dropped, valve body removed, and checked, or the cooler lines flushed out. That's about the extent of the in-car repairs that can be done. But, like I said, I'm guessing here. Sorry, I hope there's more help out there for ya, maybe somebody has another thought?

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  18. chevyracing

    chevyracing 1/2 ton status

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    Boss,
    I think there is a sensor that causes the torque converter to lock up on these vehicles when the rpm is right. If this sensor is going out it will cause what you described. Also check the connection to the tranny wires, if it is dirty it may be getting a false signal. Sounds to me like that is what is going on.

    John

    Like to go sloppin' 'round in da mud in a rapid fashion....=) [​IMG]
     
  19. Boss

    Boss 1/2 ton status Author

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    You know where that sensor is? I want to look at that too. Thanks for the suggestion! And thanks to everyone with all yalls suggestions [​IMG] My hands will be full this Sunday [​IMG]
    Boss

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  20. dyeager535

    dyeager535 1 ton status Premium Member

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    If you REALLY want to test it, unplug the connector on the drivers side of the tranny. This is only diagnostic, not long term. You can fry the tranny this way. But if the problem goes away, its the TCC solenoid.

    To me it sounds like too much other things happening for it to be the tranny, like timing is messing up or something, but it should definitely throw codes if soemthing like spark advance is messing up.


    Dorian
    My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>www.dorianyeager.com/index2.html</a>
    Why insist on counting when the ring gear has the tooth counts stamped in?
     

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