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86 Throttle Body Linkage

 
Old 02-25-2019, 05:41 PM
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Tampa 928s
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Default 86 Throttle Body Linkage



86 5-Speed
I am getting a binding that is causing the throttle to be stuck open at about 2K rpms, makes for an interesting drive. This only happens when warm, Throttle plate and main linkage tested and moved and returned smoothly. The binding seems to be at the pivot arm when moving up on the TP arm opening. I did find a little rust and when moved by hand you can feel the binding. I cleaned both pieces and added a touch of grease seems much better but do not believe this is a cure. Roger could not provide an answer if there is a bushing used on the pivot arm. I could not find any information if there was one from the factory or maybe my arm is just worn. Anyone can enlighten me or have some pictures of there set up.
Thanks
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Old 02-25-2019, 06:33 PM
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Testing showed that the metal bushing should rotate mine did not. Hit it with a little heat and lube seems to have freed it up see how it runs when installed.
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Old 02-25-2019, 08:40 PM
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Hard to tell from my memory and the photo - but is your return spring installed properly?
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Old 02-25-2019, 09:24 PM
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Hello Tampa 928s,

Here are some photos of the rebuild of the throttle body on my 1986.5:


















Good Luck!
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Old 02-26-2019, 02:21 PM
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Just did a test drive seems like things are back to normal, amazing how one little stuck part can change your life. Thanks for the pictures the TB stop adjustment is very critical and a 1/2 turn makes a big difference on idle adjustment and Icv recovery. I found this the hard way had it out twice to set it hopefully good for a while. For you 85-86 guys you can remove the TB without removing the intake tubes. Just remove the center plenum, hose from Idle control valve for room, unbolt and remove. The trick to getting it back in is to connect the connector boot to both the plenum and Tb before you rebolt the TB or you will have a hard time lining things up. Takes a little finesse but hopefully this will help someone else.
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Old 02-26-2019, 03:19 PM
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Did you find that taking the linkage apart changed the throttle stop position? I've got a sticky spring in mine. I noticed the point where the spring resistance increases keeps changing. Wondering if I should take it apart or just leave it intact and try to clean it with solvent to avoid unsettling the factory throttle stop position.
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Old 02-27-2019, 02:07 PM
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No, I found it that way when I removed the TB, it did change the Tps switch and idle setting. As far as I have seen about 2.5 threads showing is somewhere near close.this adjustment makes a big difference I would take it apart check each spring separately and look for any binding. The throttle plate spring has a lot less tension and make sure your Tps is not binding. Look into replacing the O rings and lube the bearings on the shaft and if like mine make sure the metal busing is turning freely. I readjusted the idle stop went out one turn too many and the idle set screw would not lower the idle to spec with it all the way in. I used a light under the plate to allow for a uniform circle of light and make sure you mark the plate so it goes back in the correct orientation. I have never found a factory procedure to adjust the plate so this was trial and error. Anyone of these issues will make your Throttle stick so it’s better to take it apart and clean and readjust accordingly.
Good Luck
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