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Putting the pedal to the metal??

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Wallyb, Feb 17, 2001.

  1. Wallyb

    Wallyb Registered Member

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    Location:
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    I'm wondering, when going down the highway I put the pedal to the floor why is there so much pressure doing that? I mean I have to really apply alot of pressure just to get it to the floor! Plus it kinda just maintains the speed and then I let off the pedal a slight amount that's when you can feel it picking up speed? It shoud be kicking down and picking up speed when I put it to the floor, shouldn't it??
     
  2. pr1aw

    pr1aw 1/2 ton status

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    Fuel injection, 2 barrel, or a 4 barrel.
     
  3. 90K5

    90K5 1/2 ton status

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    It probably has something to do with the accelerator spring being stiff. All the K5s and old chevys I have driven have been like that.

    90K5

    See my truck at <A target="_blank" HREF=http://albums.photopoint.com/j/Albumindex?u=1329584&a=9886502>http://albums.photopoint.com/j/Albumindex?u=1329584&a=9886502</A>
     
  4. blazercrazy

    blazercrazy Registered Member

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    Get a generic spring and adjust it so it's comfy

    Make sure your truck is the muddy one! [​IMG]
     
  5. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Well your Bio says "90 FI" so I asume that's the truck we are talking about since it wasn't mentioned in your post. My guess for the hard throttle is your bottoming out the TV linkage or your flexing the brackets. I would pull the cleaner and have somebody floor it (not running of course) and watch the linkage and see what one it is. If it is just the TV bottoming out then it should be no big deal. If it is flexing the brackets then quit pushing it so hard [​IMG]
    Now as for why it feels like it pulls less when floored will depend on what you find after checking the throw. If there is still movement in the throttle plate all the way to the floor then my guess is the TPS is running out of travel and not signaling the ECU. It might be slightly out of adjustment. Also on some FI (not sure on the GM since I have not owned one) but at full throttle it Kicks out of closed loop and goes to a extra rich condition to help prevent detonation. It may be that for some reason that is failing or there are other problems like your getting into a detonation issue. I believe the 90 had a knock/detonation sensor and under full throttle it may be seeing detonation occuring and backing off the timming advance to stop it resulting in a loss of power.
    Might just start by going through the truck and doing a good tune up including a new O2 sensor if it's old and new fuel filter. Check the TPS for proper adjustment as well as setting the timing. You didn't indicate a check engine light so what ever is causing it should be minor but it would be worth reading the codes. Sometimes a "soft code" will occure and be logged that may not be enough to trip a light. Reading the codes will reveal any "soft codes".
    Nice little trick that can be used is while you got your timming light hooked up to set the timing you can point it at the injectors and see the spray pattern. Make sure it is a good even conical pattern with no dribbles. If it's dribbling or poor pattern it could be having a poor burn and throwing of the mixture as read by the O2 Sensor.

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

    Wallyb Registered Member

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    Thanks everyone!...........adjusted the spring, so I'm hoping that'll do the trick!!
     

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