Throttle Plate Clearance
 

How do I adjust the primary throttle plate clearance on an '87 NA? I'm looking at the FSM now and it says the clearance should be 12 degress (0.8–1.4mm) when the seconday starts to open, mine are 0, dead closed. I can't see in the FSM which tab I am to bend to get proper clearance. I had done the throttle body mody last year—removed the secondaries and now I'm not sure what the clearance of the primaries should be. Should they be slightly open at idle without the secondaries in?

B

Don't worry about plate clearances - what matters is that the engine idles.&nbsp You shouldn't be messing with the TB anyways.


-Ted

LOL!

Thank you Reted.

So, the primaries, without the secondaries, should be completely closed at idle? You see, I can't remember if I changed anything when I did the TB mod. I'll leave the plates as they are.

B

The Mazda FSM claims the 5-speed manual options to have a slight clearance.&nbsp For some reason the auto trans options can have them totally closed.&nbsp I wouldn't worry about the clearances once you have the engine up and running and idling fine. :)

That's what the idle screw and throttle stop screws are for. :)



-Ted

REted: That's what I needed to know.

Which is more preferable for adjusting the idle on an N/A—the idle adjust screw on top of the plenum or the bac screw on the BAC (I can do both.) Hmmm, should I just screw down the idle adjust screw fully and use the BAC to adjust my idle? I'm not sure if doing it that way would affect my idle under A/C load. I don't know where I would turn the BAC screw to set it for factory setting. I'll go mad trying to find the right combo of BAC valve, Idle screw, idle mix, throttle stop and fast idle screw. AND(!) there are TWO throttle stop screws on either side of the throttle body. Did I mention that you can also adjust your idle with the dashpot!?!?!?

I would like for someone to tell me/us where to start with everything. For example: completely screw in your BAC valve, remove your dashpot, disengage throttle stop, fully turn idle screw clockwise. Basically, should I start with all components "disengaged" and start with the BAC valve (or whichever you tell me) and work my way up from there?

I think I'm making it more difficult than it really should be.

B