Throttle shaft and blades stuck closed on my spare TBI unit. Any suggestions on getting the shaft free? It's been sitting on the shelf for a number of years.

 

Penetrating oil, a propane torch, and prayers. Let it soak, see what happens. If it won't free-up, warm the casting a bit with the torch. DON'T melt or distort the casting by overheating it.

If you force the shaft, you risk twisting it, so that the two throttle blades don't align any more. One blade may close, while the other is still somewhat open. Don't force the throttle shaft.

Once you free-up the throttle shaft, you may discover that the rust that seized the shaft in the first place has scored the bearing area of the throttle body. Then you may have vacuum leaks through the shaft/bearing area. When this happens with carburetors, the throttle blades are removed, the shaft pulled out of the throttle body, and the throttle shaft holes are bored oversized, and bronze bushings are installed. I don't know of anyone doing this with TBI units, but there's no reason it wouldn't be about the same procedure.

The trick is to bore the oversize throttle shaft holes concentric with the original holes. After that, you need to press the bushings into place. A machinist I know uses bronze valve guide liners, cut-to-fit.

 

I had some unexpected time today. So I just did the TBI mods to the unit that is on the car. Guess the TBI unit base that was on the shelve is going into the scrap pile.

 

Yeah, don't even try to salvage it. That way, you can spend more money later when you need parts from it; or if something happens to the one you have. And it would be a shame for you to learn something, or to gain a new experience.

 

I have no qualms about putting that throttle body base in the scrap pile, they are a dime a dozen. I saved the rest of it.

 

Nice. Around here, a TB assembly is about $60/each. More for the ones from a 454.