Sticky Throttle Problem

[broncosbybart]

i had one throttle body do as you are describing. it was a mechanical issue with the butterfly shaft being worn and the butterfly sticking against the side of the TB.

[chuzie]

If you are gonna be removing the TB I would recommend performing the half shaft modification.

[rtj731]

OK Flyboy
Whats the half shaft mod?????

[SC74]

Update...

I first tried to do as Nick said and hosed down the linkage and throttle spring with some PB Blaster. That didn't help.

Next I removed the throttle body and cleaned the inside with brake cleaner. That didn't help.

Next I sprayed some PB on the top and bottom of the butterfly where it pivots and let it sit. That didn't help.

The butterfly does not seem to have any spring on it's own. Maybe a sporadic jump in it when I work it back and forth, but no consistant spring to make it want to return to closed. How "closed" is the butterfly supposed to be at idle? Is there supposed to be any opening to it or is is supposed to be closed all the way and breathe through just the little hole in the butterfly and perimeter?

[chuzie]

It is supposed to spring back from full open without assistance and be closed to the extent that it will be 90 degrees to the airflow (fully closed). When it is fully closed, the IAC takes care of the flow.

Are you sure the spring is not broken or that is has not fallen off the retainer?

[SC74]

Brought it to work today and took it apart. The butterfly shaft is bent (unless it is supposed to be bent) and this must be causing the drag. Keith has a spare that he needs for the housing so I'm going to rob the butterfly and shaft from it to see if it cures the problem.

[chuzie]

So you removed the two screws from the butterfly to remove the disc? Well, if you went that far, I would recommend performing the half shaft modification since you have to use new screws anyway. Don't forget the loctite!

[SC74]

Yes, removed the two screws from the butterfly and dropped the shaft out. Not sure what the half shaft mod is and I re-used the old screws. I have not put it back in yet but will be sure to add some locktite on them before I re-install.

[chuzie]

The stock screws were hollow so the tips could be crimped to prevent them from backing out. Unless you can find replacements you just have to use locktite.

Check out the halfshaft mod here. It is a good opportunity to get rid of some of that high pitch squeal we experience with our filter setup not terminating in the wheel well. Basically you are cutting on of the two shaft halves off, grinding our some of the throttle body edges, and smoothing the disc slightly.

Good luck.