engine won’t idle with newly remanufactured throttle body

Because of binding at the accelerator bushing, I obtained a re-manufactured throttle body for my 1989 S-10 Chevrolet pick-up with a 4.3 liter engine. The engine, with the new throttle body installed will not idle down. The old throttle body worked ok with proper idle and the computer had been replaced previously with a new one because the old one failed. I went with the re-manufactured one because the binding of the old one caused the accellerator to suddenly give and you would suddenly speed the vehicle forward. In other words, there was not a smooth travel of the accelerator and when you pushed on it with your foot, you had to press hard and then it would suddenly give with more speed than you wanted.

Does anyone have any ideas? I understand that there are adjustments on the throttle body itself. I disconnected the battery overnight thinking the computer might need to reset itself but there was no effective change. I hope that I have made myself clear.

Reply to
jay
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There is a minimum idle throttle plate clearance on the side of the TBI unit that work together with a idle control valve which is controled by ECM. If plates are set too wide open at a idle, the will not idle down enough. ALso, if you had just removed and cleaned the throttle shaft from old TBI unit, it would have worked okay as some times they can gum up a bit.

Reply to
SnoMan

There is a minimum idle throttle plate clearance on the side of the TBI unit that work together with a idle control valve which is controled by ECM. If plates are set too wide open at a idle, the will not idle down enough. ALso, if you had just removed and cleaned the throttle shaft from old TBI unit, it would have worked okay as some times they can gum up a bit.[/quote:53064d72f6]

Sorry, I neglected to say that the throttle shaft was cleaned by Chevrolet service people and I was told that the shaft was binding because of failure of the bushing. With the vacuum when the engine was running the binding caused the shaft to not move smoothly. Thanks for your reply.

Reply to
jay

binding

There is a minimum idle throttle plate clearance on the side of the TBI unit that work together with a idle control valve which is controled by ECM. If plates are set too wide open at a idle, the will not idle down enough. ALso, if you had just removed and cleaned the throttle shaft from old TBI unit, it would have worked okay as some times they can gum up a bit.[/quote:2f89acf125]

Sorry, I neglected to say that the throttle shaft was cleaned by Chevrolet service people and I was told that the shaft was binding because of failure of the bushing. With the vacuum when the engine was running the binding caused the shaft to not move smoothly. Thanks for your reply.[/quote:2f89acf125]

check adjustment of minimum idle speed screw and fucnction for idle control valve too and proper TBI to manifold gasket too.

Reply to
SnoMan

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