Throttle body question.
 

I am in the process of polishing an uim and throttle body, which is a second set off the car. I noticed on the throttle body that on wot the double throttle plates don't open all the way. When the single lower plate is fully open the upper plates are about 2 to 3 degrees from being fully open. I can move the double throttle plates to fully open by hand and it looks like it is due to slack in the interlink between the upper and lower plates. Should I be concerned about this as a reduction in flow, and can this be adjusted? I searched the forum and only came up with idle and tps adjustment. Note: I have removed the wax rod mechanism, including the spring and control arm.

I made a new link and new metal bushings to correct that on my car after I bored the barrels and made bigger plates . .I also replace the screws holding the plates to the shaft with counter sink allens after counter sinking the shaft.This get the screw heads out of the airflow .I ported one tonight and removed the hot wax rod ,cam and lower water nipple .When removing the cam I make a spacer to replace the parts behind the TPS .

Mine were off by a degree or two as well.

I have a spare throttle body here and the top plates don't completely open either... From fully closed the bottom single plate cracks open first THEN the top two plates start opening after a few more degrees of turn. I'm thinking Mazda did this to create a smooth throttle response from a fully closed throttle...of course at the expense of not having completely open top plates at WOT. Who knows I could be wrong...

Looks like it's a pretty easy fix though...at fully closed position all you have to do is bend the small metal tab to lean against the mechanism that pushes the top plates. Basically take out the slack...





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Garco, is this something you have to do or just something that you like to improve? I just took off my fast idle cam and it doesn't look like I need to touch anything behind the TPS...


sorry to go off topic a bit.





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Thanks guys for the info. I think I will try to tweak it first and if that fails I will make a new link. I know its probably a small gain if any, but I feel that the little things add up.

Pandaz Rx 7,After removing the plates you will see a tube that goes into the unit ,it slips through a rubber water seal to keep water out of the unit .The tube I put in holds the stock tube in place . Easy as that .