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Discussion Starter #1
I blasted through the TSRM last night and searched all kinds of weird threads but wasn't able to find an answer to this...

Does anyone know what the factory settings are for:

(a) Throttle Body screw - the one on top facing the front, I don't know if its controlling PCV air in or something do to with the 3 vac lines from the T.Body - all I know is that it can mess with the idle somewhat

(b) AFM screw - the cap is drilled out so I don't know what's been done with the screw setting.

I assume you thread the screw all the way in and then dial it out a certain # of revolutions but how many?

Thanks

Adam
 

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Destroyer of Turbos
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its an individual thing. the afm screw shouldnt affect idle much as it is just letting unmetered air by.
 

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Discussion Starter #4
Thanks so far guys.

I should have mentioned that its an '87 NA motor.

I can tell that the AFM screw is pretty slow to do anything but both of them do affect idle. And even if the AFM screw lets in unmetered air, the ECU will find out about it eventually from O2 readings, right? But according to that logic, the AFM mod (loosening/tightening the spring) shouldn't do much at all.

Am I correct that the throttle body screw lets a certain amount of metered air past the throttle plate? As in, if my ISC was fully closed I could still raise my idle with this screw? And if my ISC is raising my idle too much I could reduce its air supply somewhat by turning the screw in?
 
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