I stripped down a L03 TBI unit tonight for cleaning and rebuild and everything in it makes sense to me except for one part.

When you take the injector top cover off, in the center of the bridge part between the two injector housings there is an aluminum "button" shaped thing about 3/8" in diameter. It has a small "hat" in the center that sticks up and that has a small hole in the center of the hat.

I appears to be pressed in place as I can't wiggle it.

Does anybody know what this is?

I guess it could just be a plug but it looks too fancy for that.

Thanks,

Paul T.

 

I've never bothered with it when I've rebuilt a TB.
I don't know what it is, but a new one doesn't come with a TB rebuilt kit, so I've never tried to remove it.

 

I see what you are talking about, but I don't know what it is or does. I would guess nothing or maybe a vent of some sort.

 

I can't figure out what it is, it looks like there is a chamber underneath it that could even have a spring in it, so its possible its some kind of over pressure release or something like that. If it was just a plug I think they would have used a simpler part.

Is there anyone that can enlighten us on what this thing is?

Paul T.

 

I believe thats a plug thats put in place after they drill the passages.

 

its your fuel pressure regulator, you can drill out that copper ball, drill a I in it, and make it adjustable.