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Gas pedal/throttle sticking - halfway UPDATE

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by newyorkin, Jun 3, 2001.

  1. newyorkin

    newyorkin 1 ton status

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    I'm having trouble with my throttle. Engine running, can NOT press pedal smoothly, engine off, CAN press pedal smoothly. Wierd huh? Feels like crap. I have to keep pretending I'm trying to take off from lights in a hurry because I CAN'T do it smoothly. I could a month ago, though, and haven't changed anything recently (except maybe advancing the timing, but I could still press the pedal smooth then). It's almost like it's (the pedal) getting stuck, then popping out with enough force applied, which punches the engine. I tried it by hand with engine running and not, and there is a HUGE difference in pedal stiffness. What would make the pedal tighten up while running?
    My wife is ready to kill me, and my kids are going to sue me for whiplash if I don't get this fixed. Help me, guys!!

    Ratch
    **<A target="_blank" HREF=http://k5.8m.com>http://k5.8m.com</A> What more is there to life?**<P ID="edit"><FONT SIZE=-1>Edited by newyorkin on 07/13/01 11:15 AM (server time).</FONT></P>
     
  2. xnoahx

    xnoahx 1/2 ton status

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    Re: Gas pedal/throttle sticking

    You might have a kink in the cable or it could be hung up on something, I had a problem like that, it turned out that there was a little plastic collar over the trottle cable on the carb that had brocken and was binding. I just removed it and it wored fine.

    Check out my 73 K5 http://members.theglobe.com/xnoahx/73k5.htm
     
  3. xplosuv

    xplosuv 1/2 ton status

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    Re: Gas pedal/throttle sticking

    make sure the linkage is not binding on the bottom of your air cleaner.

    If you cant go over it...GO THROUGH IT !!! <A target="_blank" HREF=http://www.CaliforniaK5Krawlers.com>http://www.CaliforniaK5Krawlers.com</A>
    75 Jimmy 11" lift with 40's
     
  4. Twiz

    Twiz 1/2 ton status

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    Re: Gas pedal/throttle sticking

    If its TBI, I'll put a 20 spot on gummed up throttle bore.

    If you pull the air cleaner off, open the throttle to WOT (w/engine off) inspect the throttle bores, and just below where the throttle blades rest a idle, there should be a grimmy ring of carbon and unknown junk. This grimmy ring, seals the throttle blades at idle, so that the tip-in throttle responce sticks- baddly. To fix it, get some carb spray and with the engine running, opperate the throttle by hand to keep the engine running while spraying the carb spray into the throttle bores. Turn the engine off and spray a small amont directly onto the throttle blades, let it soak for a second or two, and restart. Use the remaining carb spary to do the final cleaneing. That should take care of the sticking throtle.

    Twiztid

    By the way, do it outside, way-outside, the fumes can bring trears to your eyes.
     
  5. newyorkin

    newyorkin 1 ton status

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    Re: Gas pedal/throttle sticking

    I am going to try it in 15 minutes (when we put the kids to bed after a loooooooong day with the K5). I was thinking something like that, intake vaccuum sucking it closed made a lot of sense, but I couldn't figure out why all of a sudden. Could this also be attributing to super-low idle (350rpm in gear warm), since the plates are sealed up?

    Ratch
    **<A target="_blank" HREF=http://k5.8m.com>http://k5.8m.com</A> What more is there to life?**
     
  6. Twiz

    Twiz 1/2 ton status

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    Re: Gas pedal/throttle sticking

    350 rpm at idle, I know some rock crawlers that would kill for that!

    The super low idle could be a by product of a a gummed up throtle bores, or a IAC problem (remembe those?) But I think the first step would be to check and clean the throttle bores.

    Twiztid
     
  7. newyorkin

    newyorkin 1 ton status

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    Re: Gas pedal/throttle sticking

    Twizted, I checked it out last night but ran out of carb cleaner when I started on it. I can't really do anything with the engine running 'cause I have to climb into the enigne compartment to do this, and my main balancing point is the shroud!
    There's some gunk just below the plates, so I'm betting you nailed it on the head. There was a tiny improvement with the small amount of cleaner I sprayed in, so I'm guessing tonight should fix it. I will yank out and clean the IAC tonight when I pick up more cleaner. Ironically, I recommended to someone else to do that during a tune-up, and forgot to do it during my own tune up...
    Maybe the IAC will fix that door closing problem too (remember Muddin's problem I suggested IAC for?)...
    I know the point of running the motor during this is to get the crap out before it can gum again, but do you think it would be a problem if I sprayed it with the engine off, then started it right away to suck the junk through.
    Thanks Bro!!

    Ratch
    **<A target="_blank" HREF=http://k5.8m.com>http://k5.8m.com</A> What more is there to life?**
     
  8. Twiz

    Twiz 1/2 ton status

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    Re: Gas pedal/throttle sticking

    You should do it with the engine running, This will help keep the engine from "flooding" and also keep large particals from going threw the engine all at once. The procedure stated above, seems to work the best for me.

    Just in case its too late. To clear a flooded engine; Hold the excell pedal to the floor while cranking, keep the pedal floored, and crank again. Then try to restart normaly. This will "tell" the ECM to go into a "clear flood" mode and shut off the fuel supplie during cranking. Its just like the old carbs.

    Good luck

    Twiztid
     
  9. ftn96

    ftn96 1/2 ton status

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    Re: Gas pedal/throttle sticking

    WD40!!!!!!

    Steve Fox for President, 2004.
    Jimi Hendrix was re-incarnated in 1990 as my....JIMI
     
  10. ftn96

    ftn96 1/2 ton status

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    Re: Gas pedal/throttle sticking

    Twisted! (what he said)

    Steve Fox for President, 2004.
    Jimi Hendrix was re-incarnated in 1990 as my....JIMI
     
  11. newyorkin

    newyorkin 1 ton status

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    Re: Gas pedal/throttle sticking only when running

    No Good. I did do it with the engine running (my nieghbors hate me... 10:30pm I'm out there revving my leaky turbo muffler system...). That puppy is sparkling now (bores above and below plates), but the pedal is still sticking when I try to accelerate smoothly. It did get a little better, though.

    I got a trouble code 13 and 43 together a few weeks ago, and most recently have been getting code 13 on long trips. Code 43 (ESC ciruit) went away after I changed the O2 sensor (but not code 13, the O2 circuit. Go figure?!?).
    Haynes says to change the TPS, which is making me think perhaps this sticking pedal and the codes are related. TPS is just a pot really, so I can't see it holding enough to make the pedal stick, and even then it would happen running or off.

    The problem is only when the motor's running, at the throttle itself, so lubing wouldn't do any good. 'Sides, that was the first thing I tried...

    Stumped anyone?

    Ratch
    **<A target="_blank" HREF=http://k5.8m.com>http://k5.8m.com</A> What more is there to life?**
     
  12. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Re: Gas pedal/throttle sticking

    Wow! I have "crud named after me!

    Diging it in the dirt with my K5's
    Grim-Reaper
    <A target="_blank" HREF=http://grimsk5s.coloradok5.com/>http://grimsk5s.coloradok5.com/</A>
     
  13. K10

    K10 Registered Member

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    Re: Gas pedal/throttle sticking

    My throttle was sticking and I replaced my throttle cable and it works great now. It was only like $10.

    <A target="_blank" HREF=http://nick.rockcrawler.com>http://nick.rockcrawler.com</A>
     
  14. newyorkin

    newyorkin 1 ton status

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    Re: Gas pedal/throttle sticking

    It's not the cable, though. The throttle itself (without the cable being connected) is different with the engine running and with it not. It seems like it's sealing up (like Twizted said), and I have to punch it to open it when the engine's running. Engine off, it feels fine, depresses smoothly...

    Anybody have any ideas on the trouble codes? O2 circuit trouble code, replaced O2 sensor, code still coming on?

    Ratch
    **<A target="_blank" HREF=http://k5.8m.com>http://k5.8m.com</A> What more is there to life?**
     
  15. Twiz

    Twiz 1/2 ton status

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    Re: Gas pedal/throttle sticking

    Shoot!!! Looks like I owe you a 20 spot!

    Check the throttle shaft, by wiggiling it back and forth, it should have no play at all. That is kinda reaching, but worth a shot.

    Try it with the throtle linkege discanected, like K10 sugjested. Start the engine and operate the throttle by hand, can you fel it in the TBI? It should help figure out what part of the sys is giveing you problems.

    You didn't say anything about codes before. I'll check my ask some of the Driveability guys tommrow and see if they have any more ideas.

    Twiztid

    If it sounds like I'm reaching for options, thats because I'am. I thought I had that sucker nailed! I'm kinda bummed now.

    <P ID="edit"><FONT SIZE=-1>Edited by Twiztid on 06/06/01 06:19 AM (server time).</FONT></P>
     
  16. newyorkin

    newyorkin 1 ton status

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    Re: Gas pedal/throttle sticking

    Yeah, I thought you had it too. Your suggestion made the most sense.
    I did try it without the cable, before and after I did the cleaning, revving by hand, and it definately is at the throttle. I'm stuck beyond that. I don't remember if I felt any play in it then. I'll check it again later, maybe the shaft is binding for some reason.
    I hacked up the funky boot/cover thing that goes over the cable from throttle to cable jacket the other day, had no effect.

    I didn't mention the codes cause I figured they were totally unrelated (saving up for another post), and I figured I'm reaching too by thinking they could be somehow related.

    What a wierd friggin problem. I will say that it has gotten a little better since I tried your idea, twizted, so the problem may actually be 2 problems, and now 1 is fixed. Ugh.

    Ratch
    **<A target="_blank" HREF=http://k5.8m.com>http://k5.8m.com</A> What more is there to life?**
     
  17. Blue85

    Blue85 Troll Premium Member

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    Re: Gas pedal/throttle sticking

    Well if there is wear in the throttle shaft or in the throttle body around it, then the butterfly may be able to move up and down a little bit. If that is true, then the butterfly itself may be making contact with the inside of the throttle bore and causing it to stick when the engine vacuum pulls down on it. That's my only guess

    <font color=green>If a K-5 is "Built not Bought", why does this stuff cost me so much money? [​IMG] </font color=green>
     
  18. jarheadk5

    jarheadk5 1/2 ton status

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    Re: Gas pedal/throttle sticking

    Hey Blue85, that's not a bad guess!! I have the EXACT SAME PROBLEM on my '87 TBI 305. Sprays of all sorts in all places, greasing the cable and linkage, even a little voodoo (OK, that's a lie...) and I STILL have the problem. The only difference I noticed was when I replaced my TBI gasket-I cleaned up the body, bores and butterflies real good while it was off the intake. I noticed the throttle shaft had some play (radial and axial), and I noticed how $&*@^% stiff the return spring was. Maybe as Blue85 said, between the shaft play, stiff-@$$ spring, and intake vacuum, the throttle shaft is being pulled out of alignment just enough that the butterflies bind in their bores.

    OK, now that we have that theory, what's involved in fixing the shaft play???

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  19. Twiz

    Twiz 1/2 ton status

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    Re: Gas pedal/throttle sticking

    Yep! I checked with one of or drivability guys today at work.

    I told him what the problem was, I said "cleaned the bores and no change" He replyed with "the throttle shaft is worn" I said "damn, Should have thought of that!"

    So
    What probabley has happend is. After several thousand miles of constant off and on throttle in-put. The shaft has worn out the aluminum TBI casting, and casusing it to bind up in the caseing. Thus, the sticking throttle when the blades are closed. Now this is what throws me, I've seen this before, but every time, it also had a high idle speed caused by a vacume leak below the throttle blades. (but now that I think about it, it could have had a bad TBI gasket too)

    The fix is to remove the TBI and remove the shaft and have the caseing drilled out and bronze bushings installed. There is a special kit for this (that I need to get), or you can have it done.

    Twiztid
     
  20. jarheadk5

    jarheadk5 1/2 ton status

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    Re: Gas pedal/throttle sticking

    OK, where can you have this done? Dealer? Good mechanic? Wait, you said kit... can this be done at home??
    I'm sick & tired of the sticky gas pedal!

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