Has anyone had any experiences where they've cleaned their throttle bodies and plates and removed this coating? I understand that it is to create a better seal when the plates are closed related to IAC functioning. I am in the process of cleaning my throttle body and some of this coating is chipped / missing.

Can I (or should) I remove it all and possible replace it? Or just clean it best I can?
Thanks

 

There is no "coating" on a stock throttlebody. You have the alloy throttlebody housing and you have the zinc/dichromate plated steel butterflies. Thats all there should be.

Perhaps what you're seeing is a thick hardened build up of old carbon and old oil. Which should all be cleaned off properly.

 

I'm pretty sure that's a deliberately applied coating

note coating on butterfly and around bore on UIM side

 

Thats just normal CAD plating on the butterflies. It's not of much consequence at all. Its not some magical "coating". Its present in the throttle bodies of Supras, Nissans, Camrys, etc. Its very much industry standard.

And not thick enough to be of any consequence except corrosion prevention.

There is no discernable "coating" on the bores either, only dark spots from repeated butterfly wear. I think you're over-thinking it. It just needs a good clean.
Thats why you haven't had many replies to this post.

 

It looks like to me that someone put some type of anti seize on the butterflies to keep them from sticking... Its not needed. Just clean the throttle body with some brake clean and call it a day.

 

Some manufacturers use a small strip of coating along the base of the throttle body bore (think speed bump) to create a better bore/butterfly seal at idle. Not sure if that is true for the FD.

 

All the FD throttle bodies I've had a look at, have that on the backside of the butterflies, so not anti-seize. Wouldn't worry about it too much. Usually dress throttle blades with a bit of scotchbrite if there's a "bad fit".

Fwiw, they're brass not steel plated too - double throttle I think, may be though if I recall. Probably be a bit reticent about spraying much in the way of a strong solvent towards the outer walls of the manifold too, if you pressure test the system, throttle shaft leaks like a sieve, which suggests the bearings don't have seals on the inside.

 

Does anyone know where you can buy the plates and shaft for the throttle body (i looked online and in the parts manual, but haven't went to mazda yet)? I removed the lower one and it took a beating coming out. It is back in but looks like crap and is severely bruised up. Also i can't remember if that shaft move freely by hand or did it need a little bit of torque. The top moves easily by hand but the bottom (one that connects to the throttle cable) is the one that is sticky.


*update* I figured out the shaft problem...it isn't suppose to stick,so my common sense was right there...BUT the machine shop bent the stupid shaft a little. Which is why it doesn't turn freely. I need this and the bottom butterfly, or plate. I went to mazda and it isn't on their secret menu.

 

You won't be able to buy a shaft I doubt. You may be able to find a junky throttle body that has a good shaft you can use.

Dale

 

the Miata has something like that too, on those it causes problems when you remove it, the Rx7 it doesn't seem too.

i think you could duplicate it with a paint

 

I posted this in error. Please delete *

 

Thanks that is actually what i ended up doing. I run the risk of the same problem again, but i'll proceed with a bit more caution in removing its screws and shaft. My throttle body is modified from stock and I would rather keep it than redo everything. Its funny your name came up in a conversation the other day talking about RX7s. Good things only mate.

 

Haha, don't talk too bad about me!

On the coating, there definitely is some sort of a coating where the plates meet the shaft. I've seen new throttle bodies with that coating, it's not just dirt or grime. Not entirely sure what the coating is but it does look like some sort of soft coating to improve the seal of the plates to the bore at full close.

Back in the day on the FC a few of us cleaned the heck out of the TB's and removed that coating and couldn't figure out why the idle was high afterwards. Had to adjust the throttle stops to fix it and it was probably metal on metal which isn't ideal.

There's no good reason to really clean a throttle body beyond a quick spray and wipe if there is large amounts of material. You don't want to remove that coating for sure.

Dale

 

It is definitely a coating, used to improve the sealing of the plates against the bore and prevent them from sticking shut.

Some people use paint or epoxy or other sealants to restore lost coating but a dry film lubricant its actually recommended to reduce friction and prevent sticking.

I bought a used big bored RC Engineering FD throttle that had the coating gone and it would idle high until I redid the coating. If you see light around the throttle plates when fully closed it may cause high idle. I used DAG213 dry film lubricant https://www.laddresearch.com/chemicals/dag-213