LT1/LT4 Tech 1993-1997

Throttle blade stop screw

Old Mar 11, 2026 | 05:47 PM
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Default Throttle blade stop screw

I think the throttle blade stop screw is a T20. I have several different types of the T20 but none will fit because things are in the way. Looks like I'll have to take the throttle body off to adjust the screw BUT I can't use the EEHACK program while it's off. Catch 22. Is there a special tool for this job?
 
Old Mar 11, 2026 | 06:29 PM
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I thought Its an Allen wrench... been a while so not sure. i said f it and used a needle nose vise grip and did my best to not harm threads in the wrong area
 
Old Mar 14, 2026 | 01:48 PM
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Well, got the throttle body off and upon close inspection it is a T20 screw head BUT it is also not very deep so a T20 bit just slips on it. To add to this problem it's a steel screw going thru an aluminum body which means it's all one piece now. Soaking it, will use a bit of heat and use the Craby method to see if I can break it loose.
 
Old Mar 15, 2026 | 11:27 PM
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I have also bent the bracket just a tad to tweak it
 
Old Mar 15, 2026 | 11:35 PM
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may old stock one was like yours and was not happy. got it cleaned and adjusted as best I could and it worked fine. I did upgrade to a 52mm
 
Old Mar 16, 2026 | 09:04 AM
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Bad info off the 'net (go figure), it's not a T20 but a T15 screw head. Good news is that it's the same size as lots of popular wood screws. A 2" T15 tool can be shortened a pit to fit in the adjustment hole so that it's not necessary to remove the throttle body. I use EEHACK to adjust the IAC valve to a count of about 40 at hot idle. Having a little problem with getting it adjusted correctly so I took the throttle body apart and cleaned it. Now I'm a bit stuck because the gaskets that I need are special order with a hefty delivery fee.
 
Old Mar 16, 2026 | 09:54 AM
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wow I cant find stock tb gasket kit. bbk has what looks like two gasket 52mm set. https://www.summitracing.com/parts/b...maro/year/1993
 
Old Mar 20, 2026 | 05:57 PM
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Took the throttle body apart and cleaned everything. Had to make my own gaskets while waiting for the special order to bounce around the U.S. Acts completely different now. When I start it the idle goes from about 900 down to 600 quickly. Idle is lots smoother and IAC count is closer to normal. Cleaning the throttle body was a good thing and my home made gaskets seem to work but will change them out to factory whenever they get here.

Short poll: how many have swapped the unvented Optispark to an aftermarket vented one?
 
Old Mar 21, 2026 | 02:00 AM
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I changed mine to newer opti style when I built and changed engine. after a while i switched to coil per cylinder.
 
Old Mar 21, 2026 | 07:23 AM
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Craby, that's interesting, coil near plug. I have seen a conversion kit where the Optispark is just a trigger to the coils and also uses a LS based ECU. As I remember the cost was around $2200. Is that what you did? How do you like it? Tune?
 

Last edited by craby; Mar 21, 2026 at 07:19 PM.

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