2G Throttle Body Sticking

kyler021 · Tuesday at 2:13 PM

Hey all,

I recently rebuilt my throttle body with new shaft seals and a FIAV delete, and now my throttle plate seems to stick. Seems simple, but the weird thing is it only sticks when the engine is turned on. I can't get the throttle plate to stick when the car is off. It doesn't even feel hard to open/close. I'll get some resistance when the car is on around 5-10% throttle but it pushes past nicely after that. Another thing I noticed is that when I turn the car off while the throttle is sticking, I'll go to the engine bay to pull it back to it's resting position and it's already there. (I know this isn't a vacuum leak or anything of the sort because DSMlink will display the throttle position when I turn the engine off and it's greater than 0%.)

TPS and IAC were working normally prior to teardown. Throttle body blade is at the correct orientation, no gouges on throttle body surface.

Things I've tried:
Loosening throttle cable
Lubricating shaft seals and shaft with silicone dielectric grease
Throttle body shaft was wet sanded to remove the gray debris that was on it
Boost leak test at the throttle body showed no visible leaks

Is it possible that I tightened the nuts on the shaft too tight? I couldn't find torque specs anywhere so I just counted the threads on the pictures I had and set it to there. I'm not even sure what else to look for... Something around the FIAV maybe? Help me out guys!

Thanks!
Kyle

Anthony Hornback · Tuesday at 2:34 PM

So it wants to stick closed? If so, is your throttle stop set to low?

kyler021 · Tuesday at 2:42 PM

Anthony Hornback said:
So it wants to stick closed? If so, is your throttle stop set to low?

Wow it would've been helpful if I included that in the original post haha, but when it sticks it'll stick slightly open. So it'll rev up to like 2000-2500 and stay there.

I am looking at videos and pictures again, and it looks like everyone puts the flush with the side of the ring thing that the seal pushes into. Would it be bad if they're recessed into the seat? Could that be putting too much pressure on the throttle body shaft causing it to catch and stick open?
Another possibility is that I never messed with the throttle stop... could that also be an issue?

Kyle

Anthony Hornback · Tuesday at 2:46 PM

kyler021 said:
Wow it would've been helpful if I included that in the original post haha, but when it sticks it'll stick slightly open. So it'll rev up to like 2000-2500 and stay there.

I am looking at videos and pictures again, and it looks like everyone puts the flush with the side of the ring thing that the seal pushes into. Would it be bad if they're recessed into the seat? Could that be putting too much pressure on the throttle body shaft causing it to catch and stick open?
Another possibility is that I never messed with the throttle stop... could that also be an issue?

Kyle

Not sure on if you can overtighten those.
I do have the experience of having my stop set wrong and sticking closed as well as being hard to start open.
Did you mark your springs before you took it apart? I doubt this would cause anything, just wondering

FIBA M - EC17PSE · Tuesday at 2:56 PM

What you have is the shaft nuts too tight and not central either. Once the casting warms up it expands a bit and jams. I have had this before and was 1/4 nut turn too tight LOL

small amount bit jams it.

Can check that and it is central with a light behind the TB to view it.
The lther thing is jamming when closed means the throttle stop is to far back. If you release it slamming shut and it jams its to fsr out and needs to just be allowed open but following the oem soecs is a good first step on that tiny screw

Anthony Hornback · Tuesday at 2:59 PM

FIBA M - EC17PSE said:
What you have is the shaft nuts too tight and not central either. Once the casting warms up it expands a bit and jams. I have had this before and was 1/4 nut turn too tight small amount bit jams it.

Can check that and it is central with a light behind the TB to view it.
The lther thing is jamming when closed means the throttle stop is to far back. If you release it slamming shut and it jams its to fsr out and needs to just be allowed open but following the oem soecs is a good first step on that tiny screw

Needed a Pro in here to shed some light!

FIBA M - EC17PSE · Tuesday at 5:08 PM

Anthony Hornback said:
Needed a Pro in here to shed some light!

Hopefully, you can resolve this, but doing it on the car can be done but might not be as precise. Ideally off the car is more ideal. Then you can clearly see the gap surrounding the plate. You will be fine and the small amount of widdle in the bar means it is working ok.

Snapping back and not jamming is the check I always do when I rebuild them so make sure to add this check at the end.

USMCGSX · Tuesday at 5:10 PM

It might just be the way I reassemble my throttles after a rebuild, but I had that same problem a couple of times and it drove me nuts. There's other possible reasons that can happen, but what worked for me was to loosen the two throttle plate screws a hair, then clap the throttle a few times, tighten one screw then clap it again a couple times and tighten the other screw. The tiny bit of play thats in the shaft screws is enough to clock the throttle plate enough that it's not seated right, but you won't notice until it gets hot.

kyler021 · Tuesday at 9:15 PM

FIBA M - EC17PSE said:
I have had this before and was 1/4 nut turn too tight small amount bit jams it.

Can check that and it is central with a light behind the TB to view it.

So basically, I just need to take the TB off, undo the 2 screws holding the throttle blade on and center it? How do you know when it's just right? When there's minimal light coming through on the sides of the housing?

FIBA M - EC17PSE said:
The lther thing is jamming when closed means the throttle stop is to far back. If you release it slamming shut and it jams its to fsr out and needs to just be allowed open but following the oem soecs is a good first step on that tiny screw

I don't think this is the problem with mine. It slams shut and it's pretty easy to get back open... Doesn't jam up or give me much resistance.

FIBA M - EC17PSE said:
Snapping back and not jamming is the check I always do when I rebuild them so make sure to add this check at the end.

See that's the thing... Even with the car running, it'll slam shut perfectly fine and open just fine, it'll just occasionally get stuck when I rev it or give it any gas trying to drive it.

Thanks all for the replies!

FIBA M - EC17PSE · Wednesday at 5:38 AM

kyler021 said:
So basically, I just need to take the TB off, undo the 2 screws holding the throttle blade on and center it? How do you know when it's just right? When there's minimal light coming through on the sides of the housing?

I don't think this is the problem with mine. It slams shut and it's pretty easy to get back open... Doesn't jam up or give me much resistance.

See that's the thing... Even with the car running, it'll slam shut perfectly fine and open just fine, it'll just occasionally get stuck when I rev it or give it any gas trying to drive it.

Thanks all for the replies!

It might be the internal screws but more than likely it is the nuts on either end of the shaft. (Under the tps and out back of the springs) Having these too tight or off center can cause sticking. This is what I said was my main issue before as it was slightly tighter one side and caused a bind.

kyler021 · Wednesday at 12:11 PM

I think it's probably time I just get a new throttle body... No matter what I do nothing changes. I've loosened 1 shaft nut at a time, loosened both at the same time, taken the TB off, centered the throttle blade, tightened the nuts while the blade was as centered as it could be and still nothing.

I did notice that when I force the shaft towards the TPS side, it gets caught on the side of the throttle body housing. When I force it to the throttle cable side it won't catch. I don't even know anymore

. I'm trying to get this POS tuned and this is the only thing preventing that. It's probably just easier if someone else rebuilds it.

dwb · Wednesday at 12:35 PM

Not sure if 2g is same, but I seem to recall a similar issue after I rebuilt my 1g TB. It was many years ago and if I recall correctly I had the throttle plate in wrong (upside down).

kyler021 · Wednesday at 9:05 PM

dwb said:
Not sure if 2g is same, but I seem to recall a similar issue after I rebuilt my 1g TB. It was many years ago and if I recall correctly I had the throttle plate in wrong (upside down).

I originally did that... Now that's all good. It wouldn't even open half way when I had it flipped haha.

chrysler kid · 2026-06-18T18:59:42-0500

I messed up twice rebuilding one and gave up

First time I installed the throttle plate in backwards, which also damaged it. Caused it to have a ding on the edge of the blade

Second time the new seals leaked worse than the original which caused an irratic idle. Ended up buying a used one on eBay and it worked fine enough to daily drive the car

I’m not sure what intercooler elbow to the throttle body you are using, but to this day removing the elbow from the throttle body causes me trauma because the lower bolt facing the valve cover is absolutely diabolical if you have anything other than the stock upper intercooler elbow. Then I’d have to take out the battery to get the rest of the pipe out

So yes I recommend getting a new one, I’ve never had success rebuilding one

kyler021 · 2026-06-18T19:19:08-0500

chrysler kid said:
I messed up twice rebuilding one and gave up

First time I installed the throttle plate in backwards, which also damaged it. Caused it to have a ding on the edge of the blade

Second time the new seals leaked worse than the original which caused an irratic idle. Ended up buying a used one on eBay and it worked fine enough to daily drive the car

Yep I also put my throttle plate in upside down the first time... I think I dinged up the blade and the housing. I wet sanded with 800 grit till I didn't feel any dings with my nail and put the throttle blade in correctly, and it wont ever get bound up while it's off the car. For some reason, it only gets stuck on the car and once I turn the car off while it's stuck, it somehow gets unstuck.

I wonder if it may be an ISC or TPS issue maybe? I'm not sure if they can make the throttle plate get stuck open or not. It's so confusing to me because it only gets stuck sometimes. Usually I can force it to get stuck but it's easily unstuck once I pull up on it. Doesn't feel like it's binding on the housing or plate or anything like that.

It's going to Shaun at AO Customs. I wrote a little note in the package to let him know what was going on. I guess he'll tell me if I need a new housing or blade.

chrysler kid said:
I’m not sure what intercooler elbow to the throttle body you are using, but to this day removing the elbow from the throttle body causes me trauma because the lower bolt facing the valve cover is absolutely diabolical if you have anything other than the stock upper intercooler elbow. Then I’d have to take out the battery to get the rest of the pipe out

I got so fed up with this. I must've done it 10 times in the past week and a half. Almost sold the car everytime

.

I'll update the post once I get an update from AO Customs on my rebuild.

-Kyle

1990TSIAWDTALON · 2026-06-18T22:42:57-0500

Ok,.not sure if it's been brought up but all of the help has been good so I didn't ask anything.
Are you SURE you got the TB springs wound exactly the way they should be?
I mark my Throttle Plates and Throttle Springs. Ya know, UP, Out or whatever. I mark the twin springs with a black magic marker with a straight line before disassembly. If the springs aren't tight enough, the Throttle "could" hang. Idk if that is whats happening but just another idea. The other guys had the rest covered and thanks guys!
If the springs are marked with a straight line, they will only line up correctly (or the way it was before disassembly) with the correct turns for loading the throttle shaft.

Marty

kyler021 · 2026-06-19T08:15:38-0500

1990TSIAWDTALON said:
Ok,.not sure if it's been brought up but all of the help has been good so I didn't ask anything.
Are you SURE you got the TB springs wound exactly the way they should be?

Yep! I took pictures from before and matched them up. So that part should be good.

I may have found something? If anyone can take a look at this log for me... that would be appreciated. I'm not sure why I didn't look at this before, but does that ISCPosition look weird to anyone? It's 2-5 at idle and when the throttle sticks it's at around 25 ish. The throttle sticks at ~1200 seconds and ~1400 seconds in the log. I'm not sure if the ISC can make the throttle stick or not but it's worth a try.

Thanks for reading!
Kyle

1990TSIAWDTALON · 2026-06-19T09:06:38-0500

Kyle, did you say it only sticks when it is running? Have you cracked the throttle plate open a half turn more on the Idle Stop Screw? The ISC should control the idle, even if the blade is opened up just a smidgen more, which would keep the plate from sticking in the bore. I've rebuilt carbs (and TB's since they came about) almost all of my life. You need to have a slight opening in the TB blade and be able to see a "corona" around the blade when its shut with a light behind it. That keeps it from sticking.
I'd open the blade setting slightly.
Marty

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2G Throttle Body Sticking

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