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Suggestions needed !! Truck is pinging badly..

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by rocko, Jan 26, 2001.

  1. rocko

    rocko 1/2 ton status

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    I did a tune up on my truck, changed the oil, only put premium gas in it. And with the slightest acceleration it pings really bad. And it doesn't go away no matter what speed except Idle.
    Any ideas what this might be before I buy a new carb?
    Timing? Bad Carb?
    Thanks guys... sorry if I'm beating a dead horse with this issue.. I have to have my truck ready for tomorrows Slab run..

    (updated) <A target="_blank" HREF=http://www.rocko.coloradok5.com>http://www.rocko.coloradok5.com</A>
     
  2. Emmettology 101

    Emmettology 101 3/4 ton status

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    Check you timing first...



    Mike [​IMG]
    See <font color=green>EMMETT</font color=green> -&gt; <A target="_blank" HREF=http://emmett.coloradok5.com>http://emmett.coloradok5.com</A>
     
  3. rocko

    rocko 1/2 ton status

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    Thanks much Emmett.. any other suggestions in case it's not the timing?

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  4. Emmettology 101

    Emmettology 101 3/4 ton status

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    I went into the post thinking of a few things and then had a brain fart when I started typing...

    You said you use premium gas, so that area is good.

    Have you done a cap and rotor change lately?

    I bet maybe your timing is off.. Or, if you have alot of miles on that engine, there is a possiblity that your timing chain may be stretched and jumped..

    I would check the timing... Sounds like it is off if it pings all the time will driving. And if it is way off it may be time to change the timing chain it the pinging just started all o a sudden!
    How is the performance since it started pinging?

    Mike [​IMG]
    See <font color=green>EMMETT</font color=green> -&gt; <A target="_blank" HREF=http://emmett.coloradok5.com>http://emmett.coloradok5.com</A>
     
  5. rocko

    rocko 1/2 ton status

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    Thanks again Emmett..
    I changed the cap and rotor, plugs, wires, oil change.. and it still pings. I run premium through it all the time.
    I'm thinking it's the timing.. the engine sounds healthy at idle, no ticking, knocking whatsoever. Just pings under load at all speeds.
    She just doesn't have any power when I mash the pedal ..I have to ease the truck up to speed.. to keep the pinging down. lol
    I'll check the timing tonight..
    Thanks again.

    (updated) <A target="_blank" HREF=http://www.rocko.coloradok5.com>http://www.rocko.coloradok5.com</A>
     
  6. JimmyDie6.2

    JimmyDie6.2 1/2 ton status

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    TIMING, TIMING, TIMING...start there!! did you set it??? Did you use a light?? turn the distributor clock wise, only a few degrees 3, 4 or 5. you don't need much. do this soon or you'll crack a piston or/and burn holes in the top of it.....if you go to far clockwise, the motor will backfire, so be careful and use a light......js
     
  7. HarryH3

    HarryH3 1 ton status Author

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    Is the vacuum line connected to the EGR valve? EGR does a lot to prevent pinging under part throttle.

    Did you disconnect the right stuff (vac line or ESC wire, depending on the year) before setting the timing? If not, then you would have set it so that it's advanced way beyond where it should be.

    <font color=black>HarryH3 - '75 K5</font color=black>
    <A target="_blank" HREF=http://ThunderTruck.ColoradoK5.com>http://ThunderTruck.ColoradoK5.com</A>
     
  8. HarryH3

    HarryH3 1 ton status Author

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    I just thought of something else. Didn't you just put headers on this truck? The headers will lean out the engine a bit. If all else checks OK, you may need to richen the mixutre a bit to get things back to normal. If you're running a Holley, you can just swap to the next larger jet size. On a QuadraFlush [​IMG] you get to play with jets and metering rods.

    <font color=black>HarryH3 - '75 K5</font color=black>
    <A target="_blank" HREF=http://ThunderTruck.ColoradoK5.com>http://ThunderTruck.ColoradoK5.com</A>
     
  9. Phyte

    Phyte 1/2 ton status

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    Harry I think you nailed it.. Rocko and I put headers on his blazer about a week ago. We are going to adjust the timing tonight to see if that fixs it(I'm sure it will)

    Phyte
     
  10. redbeast

    redbeast Registered Member

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    Hey Rocko.
    Youve probally fiqured it out by now.. But here is my .02. You just added Headers, most lackly leaned it out a bunch.. If its a Quad jet going to have to change metering rods to fatting it up. Also you might try to raise the metering rod hights. this to will allow a little more fuel in under low vaccum.Its that 1/4 plug in frount top of carb in frount of the air horn.. Remove the plug by very carafully drilling a small hole in it a putting a self tapping screw in it. Dont have to drill all the way through just enough to start the screw. Then get a small pair off dykes a gently pull the plug out.. Once out shine a lite down the hole an you will see a small d shaped adjustment screw in it. raising the screw (counter clockwise) richings Clockwise or lowering it leans it out.. Hope this helps. Have fun at the Slab.. By the way I live in San Marcos jus down the road from you. Would be interrested in some wheeling sometime.. Jus E-mail me its on my Bio...
     
  11. Mr Red

    Mr Red 1/2 ton status

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    Using the wrong gas. Premium is too high an octane for my '86. Anything higher than 87 octane will cause carbon buildup 'cause the fuel has a longer burn time and doesn't fully combust----read: Carbon build up.

    I'd go w/ checking timing and maybe richen things up for the headers but I'd certainly pour a can of GM top engine cleaner in it. Then, I'd fillup with 87 octane and two cans of BG44K to keep the carbon away.

    [​IMG]
    <font color=red>David, '86 & '91 K5</font color=red>

    I'd lean toward the
     
  12. rockosangel

    rockosangel 1/2 ton status

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    Well, guys, they are now working on Phyte's truck. In the parking lot of a parts store, go figure. We were getting ready to start checking the timing and Phyte calls, his truck won't start! The irony. They have been at it for a couple of hours, hopefully they get it figured out soon.
    Mr. Red, thanks for the advice on the premium, but it is the only thing that it runs well on, the lower octane makes it run like crap. But thanks for the .02 anyways. Never can tell, but I bet you guys are right about the headers....Hopefully it is just the timing and we wont have to get up at 5am, just to do that...Heck if I knew what and how to do it, I would go out there and do it myself!

    <A target="_blank" HREF=http://www.rockosangel.coloradok5.com>http://www.rockosangel.coloradok5.com</A>
     
  13. windrider

    windrider Registered Member

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    I have seen the balancers spin on the rubber so the timing marks may be off. I had it happen to me. Especially if you rev it to the moon!
     
  14. rocko

    rocko 1/2 ton status

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    Well, got Jason's truck running.. he blew a fusible link on the firewall.. Problem solved after replacing the starter and ignition switch. lol lol .
    We finally adjusted the timing.. turned between 4 and 6 degrees.. the truck ran the best with this setting. Lot's more umph! !!!! to it. And the pinging stopped under load at all speeds. Thanks everyone for your input.. very valuable resource here... Guess that's why we all come back day after day... Really appreciate everyone's suggestions ..
    And Jason.. Really appreciate you coming over to help out with the timing.. Lets go wheeling..


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