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How Is the Throttle Plate Stop Screw Adjusted?

Posted: Tue Oct 21, 2008 8:01 am
by lavabit
I'm wondering how to adjust the throttle plate stop screw on my 1993 Legacy with AT and no turbo.

I'm positive that someone who didn't know what he was doing has already fooled with it.

I may have missed it, but I didn't see anything about how to do that adjustment in the closest service manual for my year that I could find on the Net, the one for the 1992 Legacy.

Posted: Tue Oct 21, 2008 4:35 pm
by dzx
they're set from the factory, but the white mark on the screw should be line up with the white mark on the plate that's painted on.

Posted: Tue Oct 21, 2008 6:56 pm
by Legacy777
If it's been messed with, you may want to look at picking up a used throttle body. You should be able to get one for cheap.

Once the throttle body stop screw has been messed with, getting that throttle body back to where it was from the factory is near impossible.

The throttle position sensor can be adjusted/calibrated where it should be, but getting the stop screw back isn't as easy.

Re: How Is the Throttle Plate Stop Screw Adjusted?

Posted: Wed Mar 14, 2012 3:41 am
by 91Beater
My car idles at like 1500 and I'm sure the screw's been messed with. I mean the adjustment stop screw with a spring on top of the throttle body, not the one on the bottom where you shim with a feeler gauge for adjusting TPS.

What do I do?

How Is the Throttle Plate Stop Screw Adjusted?

Posted: Wed Mar 14, 2012 5:50 pm
by entirelyturbo
You're not supposed to mess with either of them. Subaru themselves have called the throttle body a non-serviceable part.

As Josh/Legacy777 suggested, I would look into getting a used throttle body from a junkyard. I made the mistake of adjusting both of those screws, and I ended up having to replace mine too.


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Re: How Is the Throttle Plate Stop Screw Adjusted?

Posted: Wed Mar 14, 2012 6:14 pm
by 91Beater
DerFahrer wrote:You're not supposed to mess with either of them. Subaru themselves have called the throttle body a non-serviceable part.

As Josh/Legacy777 suggested, I would look into getting a used throttle body from a junkyard. I made the mistake of adjusting both of those screws, and I ended up having to replace mine too.


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The bottom one is not so tempting to a tech/DIYer, but I think the top one is very tempting "go to" adjustment. When you get a throttle body from the junkyard, its a hit and miss, because whoever had a problem with the car it was attached to may have messed with it also.

You'd think that there would be a way to adjust the top one in reference to the bottom one.

I'll have to look at the TB again, but whats the difference between the top and the bottom one?

Re: How Is the Throttle Plate Stop Screw Adjusted?

Posted: Thu Mar 22, 2012 5:39 pm
by Legacy777
Look for white paint across the stop screws. If they haven't messed with, the paint will be in tact.

As for the difference between the top and bottom screws...not sure.