After installing my new 58MM TB, the blades stick only when the car is running. I had to slot the tps, fabricate a throttle stop, and the manifold is bored. The car idles fine and runs good, when I try to ease into the throttle it snaps open, and then sticks open slightly unless I blip the throttle.
As soon as I turn the engine off it moves as smooth as silk, cold, hot same thing. I can minimize the stick by opening the blades with the idle screw, but 1500 rpm idle is the result. This leads me to belive it is an airflow issue, when the blades are open with the idle screw there is obviously a opening for airflow between the blades and bores, thats why I am considering drilling the blades to alow airflow to the plenuum. Guys on the impalassforum have fixed split blm's by drilling 7/64 holes in the blades, but I have not heard about that fixing the binding. I have to stress that the blades have no mechanical binding, I have centered the blades polished the edge of the blades, same results. With the TB mounted and throttle cable/cruise control removed same thing....moves free....start car....sticks.....turn off car....free again! I do not want to turn the idle screw out and then have the IAC counts at zero...I want to find the real problem.
One other note I did try drilling the IAC passage to match the stock TB hole same problem with sticking but idle increased slightly.
Car idles fine, just need to fix the sticking without using a monster return spring!

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96DCM,230/236 comp,ported heads & Intake,Borla Cat-back,AS&M intake&Headers,exports, 3.73 gears,edge 3000 stall, probuilt trans kit, electric W/P, pcmforless, and pulleys.

 

is it a holley?

 

My BBK TB does that. I had to clean it really well with some Berryman's and then use a little WD to lubricate it. It works fine for a while and then it will do it again. Did a little reading and it seems they are known to do that so I just accept it.....for now.

 

I had the same issue with my holley. I took it off the car, and dissasembled the piece. When I looked dowm the air tunnels I could see a Groove dug in from where the blades had been hitting the TB slightly. It worked fine with the engien off, but it would get stuck at around the same RPMS with the engine on. So I took the rod out and sanded it down a bit and polished it to make sure it would never stick again, then I took the blades, and sanded the edges on them. what I think the problem is that the blades I think are CNC'd. They have edges on them, so they are not actually round when you inspect them up close. I just sanded the blades till they where actually round like they should have been, then polished the edges and reintalled them. I checked the clearance using a flashlight. If I could see light slightly hallowing around the blade than it was fine, the parts that had shadows, where still touching, which Ironically where they areas that the grooves had been worked in. When I was done I just put it back together and it was pretty smooth. Just remember only take teeny tiny bits off.

 

Here's what I did. Works perfect.

 

that looks like a good idea where did u get that spring? is your tb also a holley? does that spring have alot of tension i mean can u feel a differance when u press the gas? thanx

 

It was generic. Nothing special - hardware store type item...Answered your PM.

 

If its a Holley TB, the return spring is adjustable.

In any case, fix the "sticking" problem before you start drilling holes in things.

 

90% of the time they stick because they are closing to far. There have been many issues over the years. I prefer to only use good TBs like the LPE and the AS&M

Never had a problem with either because they were desighed well

At present I have a LPE on two of the shop cars and a AS&M on the TT Shop truck. I have had simular issues with cheap LSx TBs as well