If you're asking "should the TB blade bind?" the answer is no.
However there is an idle air adjustment screw on the 04 throttle body. It is underneath the tab where the throttle blade rests. Many people use it to crack the TB blade open to compensate for poor idle and tune issues.
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When the car is off, the tb is closed all the way. When the car is on and idling, it's still closed for the most part but a at a little different angle so that the engine can breathe enough for idling. Why would you want to close your TB all the way completely with the car running? How is your car going to run then? I don't recall even 04s having a small hold in the blade for idle air like some older cars, so the blade has to stay somewhat open to let air in.
When the car is off, the tb is closed all the way. When the car is on and idling, it's still closed for the most part but a at a little different angle so that the engine can breathe enough for idling. Why would you want to close your TB all the way completely with the car running? How is your car going to run then? I don't recall even 04s having a small hold in the blade for idle air like some older cars, so the blade has to stay somewhat open to let air in.
04's use an IAC for idle air, as well as having the hole in the tb...its also not a perfect seal around the tb blade so air gets around there...
the set screw can be used to crack the blade a smidgin to lower IAC counts, but the difference isn't even perceptable to the eye most times...
the 05 06 's use the TB blade motor for idle air control... the computer slightly opens the blade at idle to adjust idle air, which is why at idle the TPS is never zero on those cars (usually 3-6%) depending on the car...
the air needed to idle a car even a v8 is remarkably small actually..
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thanks for the responses so far, guys.
it's an aftermarket TB that i have on my 416.
to be more specific: this TB, brand new out of the box, would bind when still 3-5% open. it was physically impossible to get it closed all the way (90 deg).
when i had the car initially tuned, the tuner told me it was binding and that when i got back home (200 miles away) i should relieve the blade where it was binding.
the car was surging, stalling, and hunting for idle even before i got home.
i contacted the maker of the TB and was told to advance the set screw 1/8 turn and reset the tps. this did not help.
in desperation, i selectively relieved the tb blade to eliminate the binding so the tb blade could close completely.
the car continued to surge, stall, and hunt for idle.
i thought it was in the tune.
yesterday, edcmat-l1 was attempting to re-tune the car. he said that the TB was NOW passing too much air at idle for him to tune it. so he replaced the TB blade.
so the question remains............do they intentionally manufacture throttle bodies...........is it part of the design......to have a brand new throttle body where the TB blade does not close all the way? or was i misinformed by the first tuner? i am trying to figure out if this was a manufacturing defect or if the TB was made that way on purpose.
2004 GTO Owner
