So I picked up an Auto TB from a forum member and while it was in good shape and I shouldn't have messed with it - I did.

I took care to mess with the teflon coating on the walls of the TB, however, the plate does not quite seal (If you hold it up to a light there's some light pass through in the upper corner).

Has anyone just removed the teflon altogether and been able to maintain a low idle? I'm convinced the high idle + teflon removal is more myth and fact.

-Zach

 

Teflon coating? Never heard of a TB with a Teflon coating. Most likely its just dirt and gunk on the interior. Clean it with some carb cleaner and a toothbrush and I bet it will seal again.

 

the butterfly should never quite make a full seal.

 

The 90-93 TB's have some sort of plactic/teflon coating on the intake side of the TB. It's a gunmetal color and looks to be just painted on with a brush. I suppose it was done to prevent build up/throttle sticking over time.

-Zach

 

never heard of this or seen anything that looks painted on...

 

Wrong side, it's on the back. I'll take a picture of it when I get home.

It's pretty common on Fords, BMWs, etc.

It looks like carbon build up until you clean it at which point it becomes pretty obvious that there's some sort of coating applied - I swearz. Keith from FM has posted on the GRM boards before.

After spending 6 hours filing off all the unused bosses, smoothing flashlines and polishing the TB I'll be pretty pissed if I can't get this ****** to seal.

-Zach

 

Having worked with teflon (Xylan) coatings, and having 2 1.6L throttle bodies on hand I can safely say they don't come with any kind of coating.

 

oh this ****:

 

that would be the **** and unfortunately it's causing the plate to not 'seat'.

The mazda shop manual just mentions a 'plastic coating' but I assume it's a teflon based coating.

I'm looking for the best way in which to remove the coating with using any agressive abrasives. So far, no luck.

-Zach

 

I don't see how that contributes at all to sealing. the bottom edge wouldn't even contact the bore.

 

Every miata TB I've ever held to light has a halo around the butterfly...if it completely seals you wont idlez well.

 

hmmm ... I'll just bolt it up and deal with it later if I can't get it to idle.

I have a feeling I'm going to regret touching everything on this car at once ... too many variables.

-Zach

 

I still stick by my last point. I don't see how that "coating" on the back of the throttle plate has anything to do with sealing when the whole bottom half of the leading edge of the plate that does the sealing is the FRONT of the plate. Which btw, has no coating.

 

I don't see it either, however, according to Keith at FM (based upon a post on GRM) they constantly get high idle calls after people have cleaned their TB and they've attributed it to a tolerence change from the removal of the 'plastic coating'. I can see how it could affect the air gap to some degree as the crap was clearly painted on after the throttle stop was set and as a result, the throttle plate sorta butts up to the coating. If you remove the coating but do not adjust your throttle stop then you could in theory end up with a larger than OEM air gap.

At this point I'm just going to remove the coating then dial in my throttle stop. Any Idle adjustment can then hopefully be done with the idle screw.


-Zach

-Zach

 

Right, you should be able to trim up your idle with the screw. Also don't forget to adjust the throttle cable. Twice now when I fucked with the TB area my idle was running high afterwards and it was because the cable was pulling the throttle open.

BTW Brain, how is your chiseled up throttle doing? AOK?

 

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