I'm in the process of deleting the FIAV by closing it off as shown in this post, and I'm running into problems screwing the black plastic seat all the way in. I got it to turn maybe a 180 degrees before it stopped and won't go anymore.

The plastic just breaks away when I put a ton of pressure on it with the needle nose. I am 90% sure it's nowhere near close enough to being closed, as I can still push in the center and see a fair amount of space around the valve that air can get through. I sprayed PB blaster all over it in the hopes that that would loosen it up, and it didn't seem to do much. I'm letting it sit overnight right now, so maybe tomorrow afternoon I'll get lucky.

Does anyone have any advice for getting this to turn without breaking the plastic? If not, would putting a relatively thick layer of grey RTV over where the spring loaded middle piece/valve and the black plastic screw/seat contact close off the FIAV enough? I'm somewhat wary of putting sealant all over the inside of my TB, but you all know much more than me. Alternatively, could I screw in some sort of solid metal plate with threads on the sides in place of the plastic piece if I just broke it out of there?

I'm sort of out of ideas here, since I can't do much more without breaking the part unless I'm doing something totally wrong here. If the goal is simply to close off the center of that plastic piece (and correct me if I'm wrong, because I know I understand what the FIAV does, but I only believe I understand how it does it), could I just rig up some way to do that if worst comes to worst? Attached are a couple pictures of the valve as it sits so you can see how far (not very) I was able to get it to turn. I apologize if this has been asked before, but I couldn't seem to find any threads where others had this much trouble getting it to turn and close. Thanks!

The free mod can be a PITA sometimes. If it's giving you trouble just forget it, seal up the freeze plug with some rtv and get the bypass plate. It's only $12.
https://m.ebay.com/itm/FIAV-Bypass-...858841?hash=item2aa059b059:g:ZKwAAOxy02dRgSCv

Damn, was hoping not to have to spend the money. I guess I’ll try it again tonight and if I can get it, I’ll just buy the plate. I guess if it’s seeing the whole 10-15 lbs of boost going through the intake, it’s gonna need to be something more solid than just rtv holding it closed.

I second the bypass plate. Do it right and do it once. To many people try to cut corners and give these cars a bad rap...

Pull the plastic piece all the way out and clean the threads in the bore.

donniekak said:

Pull the plastic piece all the way out and clean the threads in the bore.

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Ding ding! You are fighting against 20 years of corrosion and water deposits. Try this method before you spend the few dollars.

I bought a plate years ago, no problems. I think I got the one from JMF, but you can find other "cheaper" ones.

Not to judge but if a 10$ plate is to much i hate to be your car when it's time to do any repair. Maybe of it was a 50 or 75$ id understand.

Dsm panda said:

Not to judge but if a 10$ plate is to much i hate to be your car when it's time to do any repair. Maybe of it was a 50 or 75$ id understand.

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It’s not that $10 is “too much”, it’s that spending $10 on something that could be free will and should leave a bad taste in your mouth. That’s $10 I could be spending somewhere else. This isn’t a “budget build” at all, but I’m trying to save money where I can. If I need to replace something, I have no problem shelling out the cash too, but that stuff adds up and if I can eliminate a purchase here and there by putting in the extra work, I definitely will.

Off topic but trying to understand this mod fully. Is there any kind of gain to doing this, or is this only done when the car is experiencing poor idle/idle surge? After reading the write up I see that unlike other cars, you cannot simply disconnect the coolant lines form the TB and loop them on this design right? Because in doing so the FIAV will never close without warmed up coolant temp and give crappy idle? Do I understand this correctly?

Meaning the over all benefit to a car "not" experiencing idle issues is a cooler throttle body for a denser air/fuel mixture?

As I understand it, there are a couple small benefits:
1. Stopping warm/hot coolant from flowing through the TB will very minimally effect intake temps - probably not even noticeable but it can’t hurt.
2. If the FIAV fails, you’ll have idle surge problems. Since the removal of FIAV won’t cause any problems besides possibly having to hold the throttle open a little on very cold starts for a minute, eliminating it will eliminate this point of failure without repercussions.

Edit: If you don’t close it but you eliminate the cooling lines to the TB, you’ll have problems because the valve will take a long time to close as it needs to be heated to the right temperature from heat in the engine bay/intake charge.

Fill the port with JB weld if you don’t want to use a plate. The FIAV is the biggest nonsense on this throttle body. The 1.8L engines don’t have it, why does the 2.0L need it?

It’s basically a thermostat for idle. A piece of wax heats up which closes the valve and opens as it cools. Screwing that plate all the way in closes the valve. That’s how you would adjust it’s operation at the factory but trying to adjust it correctly is almost impossible after wear unless you close it haha.

When you go to put the freeze plug back in and you don’t fill the port with JB weld or something, make sure to use RTV on it so it seals. It can become a vacuum/boost leak.

jcastello214 said:

When you go to put the freeze plug back in and you don’t fill the port with JB weld or something, make sure to use RTV on it so it seals. It can become a vacuum/boost leak.

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Thanks, I think I’m gonna go with this method. $2 worth of jb weld is a lot more preferable than a $12 plate.

The way you guys explained the operation of the FIAV is the way I've always understood it. Since I blocked mine off a few years ago I've noticed absolutely no difference in the car. I did when I rebuilt my 1G TB just could I have it off and I was rebuilding it anyway. I'm in PA and I only drive my car in the summer months, I remember when I was reading up on this you might want to keep it if you lived in a colder climate, like Canada or something. Other than that, it's sorta like an appendix.

I’m doing it for the same reason. Rebuilding my engine and already have it apart, so I might as well take the time to do it. It can get pretty cold around here during the winter, but the engine is going in a 1974 Colt, so I’m not gonna be driving it in the cold anyway.

zsn0w said:

I’m doing it for the same reason. Rebuilding my engine and already have it apart, so I might as well take the time to do it. It can get pretty cold around here during the winter, but the engine is going in a 1974 Colt, so I’m not gonna be driving it in the cold anyway.

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74 Colt! That's awesome. I'd love to some pics of that when it's done. Good luck!

techboy said:

74 Colt! That's awesome. I'd love to some pics of that when it's done. Good luck!

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Definitely! Thanks!