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That darn pinging...HELP! *UPDATED*

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Burbinator, Sep 14, 2001.

  1. Burbinator

    Burbinator 1/2 ton status

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    OK, my Suburban (350, Edelbrock 1904 Q-Jet) likes to ping at part throttle no matter what I do. Here's what I've verified/fixed so far : Vacuum system integrity and routing, control module, coil, plug wires, rebuilt the carb, emissions systems, blah, blah, blah. Spark plugs are the correct HR. I've both retarded and advanced the timing with no change, recurved the centrifugal advance both directions (less/more). Mixture lean or rich, no effect except for idle speed, of course. Cooling system works great. NOTHING. Vacuum is steady, timing is steady. Does anyone have any idea what I'm missing? Also, it blows a little rich on the neighborhood air quality equipment, too (AKA failed it's annual), but not by very much and runs a bit rough at idle. Maybe I should just get one of those new, shiny GM crate motors...nah, wife would freak. Thanks in advance for any light you can shine!

    - Alan

    '82 K10 Suburban Silverado
     
  2. POWERMAD

    POWERMAD 1/2 ton status

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    Re: That darn pinging...HELP!

    I don't remember what year they started puting in the Electronic Spark Control. But is your distributor a regular HEI?

    <font color=green> Too bad ignorance isn't painful </font color=green>
     
  3. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    Re: That darn pinging...HELP!

    Check that your mechanical advance operates freely- you'd be surprised how sticky the assembly can get........



    <font color=blue> MEAN DAD WITH TWO BAD KIDS<font color=blue>
     
  4. Burbinator

    Burbinator 1/2 ton status

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    Re: That darn pinging...HELP!

    As far as I know, the HEI is regular with the solid-state ignition module (i.e. no computer). If my memory serves, GM added the computers to mix in '83 or '84. That module has been replaced, along with the coil. Also, checked the mechanical advance for free operation...all good. I put in some heavier and lighter springs on the mech. advance to no avail.

    - Alan

    '82 K10 Suburban Silverado
     
  5. DuneRunner

    DuneRunner 1/2 ton status

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    Re: That darn pinging...HELP!

    Have you ever thought of putting in a Multi Spark System, (MSD, Jacob ect.)
    I know that the 6A from MSD is one of the most used boxs but the price is somewhat of a factor for some.
    Not knowing if it will fix the proble. In California the price for one runs around $160.00

    Just a thought......
    KEN

    DANGIT it's not a bronco!<P ID="edit"><FONT class="small">Edited by DuneRunner on 09/15/01 12:46 AM.</FONT></P>
     
  6. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Re: That darn pinging...HELP!

    It sounds like you have a lean condition at part throttle...do you have a slight 'surge' at steady throttle like on the freeway? How were the throttle shaft bushings on the carb when it was rebuilt?

    Rene

    <font color=green>Dyslexics of the world...UNTIE!</font color=green>
     
  7. mudhog

    mudhog THEGAME Staff Member Super Moderator

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    Re: That darn pinging...HELP!

    also try replacing the vacume advance on the side of the distributor(sp?) that is what is out on mine and it will not time out right and it also pings very badly

    wheeling videoshttp://community.webshots.com/user/ssmith6333
     
  8. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Re: That darn pinging...HELP!

    You got the factory snorkle hooked up? I was having that issue with my 75. It had the old restrictive air cleaner on it that sucked air from the engine compartment. It also had a defective Thermac control and the preheat flap was staying open after warm up. I put a mid 80's cleaner on it with the snorkle and it took care of it. I also found the distributor coked up and hanging the mechanical advanced. That was part of it but not all of it. They are easy to clean. Pull it out. Take the advance weights off. Drive the roll pin out of the gear (make a index mark on the shaft). Slides apart. Clean it with some brake cleaner and a light coat of HIGH temp grease like that is used for brakes.

    It's not my damn planet monkey boy!
    <a target="_blank" href=http://communities.msn.com/OffroadK5s>communities.msn.com/OffroadK5s</a>
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    79 Chevy Blazer, Her's
    70 Chevy Burb
    Grim-Reaper
     
  9. Burbinator

    Burbinator 1/2 ton status

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    Re: That darn pinging...HELP!

    No surge when throttle is steady; thought that might be it, too (lean). I've tried richening up the mixture with no luck, so I backed it back to where it should be (I'd like to pass at least ONE gas station on the way to work!). Primary, secondary and choke shaft bushings were all replaced. I did find today that the electric choke was misadjusted and partially closing the plates; fixed that. Will check out my vacuum advance, as per Mudhog's suggestion. The factory snorkel is in place and functioning correctly, to answer Grim-Reapers question. I heard somewhere of carbon buildup in the chambers remaining incandescent and causing preignition. Their suggested fix at the time was to dribble some ATF or water down the carb. Certainly doesn't sound like a good idea to me. Perhaps I'll yank the valve covers off tomorrow and check the lash on all of them, just in case one is being a non-team player.

    What's that I hear? I think it's a GM crate motor calling my name...

    Thanks to all of you for your suggestions. Keep 'em coming, sooner or later I'll find it.

    - Alan

    '82 K10 Suburban Silverado
     
  10. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Re: That darn pinging...HELP!

    The ATF trick has been used by several members here with good results. The ATF is high in detergent and does a nice job of cleaning carbon deposits.

    Maybe start another post asking about it...to the best of my knowledge it hasn't come up in quite a while.

    Rene

    <font color=green>Dyslexics of the world...UNTIE!</font color=green>
     
  11. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Re: That darn pinging...HELP!

    I have one other question...how many miles on the motor? I'm thinking maybe your timing chain is getting sloppy which would cause wierd timing issues. The fact that advancing and retarding the distributor a little each way with no tangible result raises a red flag for me. Try watching the timing marks with a light while its running and see how steady it stays...

    Rene

    <font color=green>Dyslexics of the world...UNTIE!</font color=green>
     
  12. mudhog

    mudhog THEGAME Staff Member Super Moderator

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  13. Burbinator

    Burbinator 1/2 ton status

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    Re: That darn pinging...HELP!

    The motor itself is a replacement GM 350 with about 60K on it now, due to the fact that the original motor was over bored too far by the previous owner and left the cylinder walls thin; cracked the block. I thought that the timing chain might be suspect myself; I replaced it last month due to some slop that was more than I cared to see. Definitely cured the timing from wavering all over the place, but the pinging remained. Yanked the covers off today to see if I had a valve adjusted too tight, readjusted them all. Pinging remains, but a little less than before. Vacuum advance checks out OK on my pump; full range of motion. Tried some heavier mechanical advance springs from my neighbors blown 350 on his boat. Decreased the pinging a little more, but hurt the power that this engine normally puts out. Think I'll try the ATF trick to see if that might be my gremlin (carbon); will advise on the results.

    - Alan

    '82 K10 Suburban Silverado
     
  14. Eagle86K5

    Eagle86K5 1/2 ton status

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    Re: That darn pinging...HELP!

    The ATF trick does work...
    Another thing to try is remove the distributor cap and watch the rotor while you manually turn the crank in one direction...once the rotor starts to move, turn the crank the other direction, if you can turn the crank more then say 10 degrees without the rotor moving then the timing chain and gears are bad. I installed a new distributor in mine, an Accel Blueprint with the new super duty Accel coil. It ran good for a while and started pinging. after checking everything you did, I found too much play in the chain and gears replaced it and it went away....good luck!
     
  15. Burbinator

    Burbinator 1/2 ton status

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    Re: That darn pinging...HELP!

    My timing chain is very new, but I checked the rotor movement just to be sure. Just because it's new doesn't mean it's good. How many times have we all run into that one?! No play at all, so I'm back to the proverbial square one. Another thing I have yet to check is compression; I have overlooked that basic thus far. I haven't gotten around to the ATF trick yet, but soon. How much would be needed to have an effect? I'm thinking that the best method would be to use an eyedropper or the like right down the airhorn? Will it affect my cat at all? Thanks to all for your input(s).

    - Alan

    '82 K10 Suburban Silverado (AKA U.S.S. Nimitz)
     
  16. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    Re: That darn pinging...HELP!

    I think one of the more popular ways to get the ATF into the system is to suck it in through the PCV valve.......



    <font color=blue> IT AIN'T NOTHING A NUKE CAN'T SOLVE<font color=blue>
     
  17. WOODYJ

    WOODYJ 1/2 ton status

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    Re: That darn pinging...HELP!

    My vote is for the tranny fluid! Sounds like you just have a carbon build up in the cylinders. Either that or run a gallon of diesel in a tank of gas. That will cut out the carbon too. Hope this helps!!

    k5woody I Don't Understand The Jeep Thing Either!!!
     
  18. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    Re: That darn pinging...HELP!

    I've heard a lot about adding diesel to help clean the engine- how does it affect mileage and performance?



    <font color=blue> IT AIN'T NOTHING A NUKE CAN'T SOLVE<font color=blue>
     
  19. Burbinator

    Burbinator 1/2 ton status

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    Re: That darn pinging...HELP!

    OK, OK...due to the overwhelming suggestions about the ATF, it's time to let the PCV suck some of it up. Makes sense to do it that way so that it mixes with the fuel rather than pooling at the bottom of the manifold. I'll let you all know how it turns out. I thought it might be carbon due to everything else being up to par and that it does it whether it's cold or at normal op temp.

    Also, found a cracked vacuum line between the PCV and the canister a little while ago. Not the problem, but I'm sure it wasn't helping, either.

    - Alan

    '82 K10 Suburban Silverado (AKA U.S.S. Nimitz)<P ID="edit"><FONT class="small">Edited by Burbinator on 09/16/01 11:33 PM.</FONT></P>
     
  20. DMK

    DMK 1/2 ton status

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    Re: That darn pinging...HELP!

    Have you tried a higher grade of gas. My 87 blazer will ping on anything but 92 octane.
     

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