Throttle flap set screw setting

[raueda1]

On the bottom of the throttle body there's a very small set screw with locking nut to set the opening of the throttle flap.  Note that I refer to the throttle flap, NOT the air flow sensor or plastic idle speed set screw.  It's clearly not something that would be routinely adjusted, you can't even get to it without removing the airflow sensor body.

Anyway, I haven't been able to find anything in the manuals about this setting.  I noticed that on my car the flap did not completely close.  The gap is very small, to be sure, but it's there.  I'd guess 0.2mm or so.  Does anybody know what the gap ought to be between the flap and throttle body bore?  Thanks as always,

[UTn_boy]

There wasn't ever anything mentioned about this in the books after the early 1970's.  Itss just not something that anyone needed to mess with.  It's actually referred to as a "stop" set screw, as it stops the throttle plate from seating so well in the throttle housing that it sticks.  However, if it makes you feel better to monkey around with it the procedure is simple.  You simply loosen the jamb nut, and then turn the stop screw until it just lifts the throttle plate off of the internal bore.  Again, it's only to keep the throttle plate from binding in the throttle bore.  In the early books no specifications were given as to gap.  Only what I stated above.  These were made by Bosch, and when new they'd not test the gap.  They's test them by measuring the air flow when the throttle plate was closed.  Hence, the lack of any set up procedures.  Then again, unless someone has messed with them in the past they don't ever really need messed with.  It's a whole different story on early 6 cylinder mechanically fuel injected cars because the stop screw is accessible, and people would monkey with them to adjust idle....which is exactly how one doesn't adjust idle on those engines. 

[raueda1]

There wasn't ever anything mentioned about this in the books after the early 1970's.  Itss just not something that anyone needed to mess with. It's actually referred to as a "stop" set screw, as it stops the throttle plate from seating so well in the throttle housing that it sticks.  However, if it makes you feel better to monkey around with it the procedure is simple.  You simply loosen the jamb nut, and then turn the stop screw until it just lifts the throttle plate off of the internal bore.  Again, it's only to keep the throttle plate from binding in the throttle bore.  In the early books no specifications were given as to gap.  Only what I stated above.  These were made by Bosch, and when new they'd not test the gap.  They's test them by measuring the air flow when the throttle plate was closed.  Hence, the lack of any set up procedures.  Then again, unless someone has messed with them in the past they don't ever really need messed with.  It's a whole different story on early 6 cylinder mechanically fuel injected cars because the stop screw is accessible, and people would monkey with them to adjust idle....which is exactly how one doesn't adjust idle on those engines.

Of course that's what I immediately did.  Curiosity and the cat and all that.     And after doing so I surmised that it must be along the lines of you clarification.  But what if it's something critical???  Hence my concern.  The plate digs in pretty hard if it's not stopped.  Anyway, thanks for the info.  I'm confident I can get it back where it was.  Thanks and cheers,