1G BISS screw stuck

[Robert503]

Attempting to adjust my biss but that little guys does not want to turn in or out more than a squeak and it will strip out with to many more attempts…. Am I okay to drop a little bit of penetrating oil on top of the biss screw? Not sure if it will hurt anything in the throttle body side

 

[2gmitsueclipse]

Is your biss screw plastic-like or metal?

 

[Robert503]

Is your biss screw plastic-like or metal?

Metal

 

[19Eclipse90]

I'm surprised the metal screw is giving you trouble. A little oil won't hurt anything. Make sure to use the best fitting bit for it to minimize risk of stripping it out.

 

[2gmitsueclipse]

Metal

You could try a small amount of penetrating oil such as PB-Blaster or Kroil. This is the drawback of the metal BISS screw over the plastic one. At minimum, you'll want to replace the o-ring. Some anti-seize would be helpful for next time if you're able to remove the screw undamaged.

 

[19Eclipse90]

I didn't realize this was a common issue on the metal ones. All the ones I've pulled from the junkyards, if they didn't screw out completely, I'd pull the throttle body and poke them out from the inside.

And of course, this isn't as uncommon as I thought... Biss will not come out [Merged 6-7] removal stuck remove take out

 

[Robert503]

I'm surprised the metal screw is giving you trouble. A little oil won't hurt anything. Make sure to use the best fitting bit for it to minimize risk of stripping it out.

It’s so incredibly tight I can barely get it to squeak counter clockwise. It didn’t have the rubber plug for the biss when I got the car, idk if that’s the issues but there isn’t corrosion in the hole. Seems like it could have got messed up by a previous owner. I’ll probably just pull the throttle body off at this point and see what it looks like on the inside.

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You could try a small amount of penetrating oil such as PB-Blaster or Kroil. This is the drawback of the metal BISS screw over the plastic one. At minimum, you'll want to replace the o-ring. Some anti-seize would be helpful for next time if you're able to remove the screw undamaged.

I tried a proper fitting flat head bit on a 1/4 drive ratchet and it doesn’t want to budge, I’m also trying not to slip off and strip it all the way but I gave it a good amount of pressure and it didn’t budge

 

[2gmitsueclipse]

It’s so incredibly tight I can barely get it to squeak counter clockwise. It didn’t have the rubber plug for the biss when I got the car, idk if that’s the issues but there isn’t corrosion in the hole. Seems like it could have got messed up by a previous owner. I’ll probably just pull the throttle body off at this point and see what it looks like on the inside.

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I tried a proper fitting flat head bit on a 1/4 drive ratchet and it doesn’t want to budge, I’m also trying not to slip off and strip it all the way but I gave it a good amount of pressure and it didn’t budge

It may have been bottomed out or cross-threaded. The thread is very fine on this particular screw. Pulling the throttle body would be a good idea at this point. You might have luck using a manual impact screwdriver. For reference:

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[99dsmer4g63]

I typically use a #2 square screwdriver on the 2g biss. Not sure if the 1g is the same but the square #2 fits the best IMO. I would order a new one and then remove the existing one and replace it if you can.
-Daniel

 

[Robert503]

I appreciate the replies. I ended up getting it out, it was all the way tightened and corroded some. O ring was bridle and broke getting it off. It’s definitely got some issues somewhere in the idle system/ vacuum leaks. I’ll have do dig into it and see what’s been messed with or not working properly. It’s currently biss all the way in(how I got the car) and ips not fully set to spec as it should be 15/16 turn after you get continuity, the ips is set to just making continuity and then the lock nut tightened. I assume that was done to achieve a lower idle getting it to about 1100 rpm so that’s where I left it and made sure the tps was reading correctly. I was also having issues with my isc, when I installed the new one it would idle around 3500 cold so I reinstalled the old one for now. I’m just not sure where to start, I assume boost leaks test is a good starting point

 

[2gmitsueclipse]

Since you have the throttle body off, would be a good time to rebuild it. Shaft seals are a common pressure leak point.

 

[19Eclipse90]

Yes, absolutely boost leak test. If the BISS was all the way tightened down, it was masking some other issue with the system. And if the O-ring was broken or torn, that's a leak that would cause issues - and not likely the only one you'll find.

 

[2gmitsueclipse]

For reference, from my build thread:

Have been itching to take care of some large pressure leaks from the throttle body shaft seals on the red Summit. Opted to go for the HD shaft seals for this rebuild. 91-99 DSM shaft seals will work for the Evo III throttle body. Really need to get myself one of the shaft seal install tools. Fuel injector upper and lower seals were also replaced (common pressure leak). Some words of advice if you try this:
-Keep all components together and take pics for reference.
-Mark springs/sensors/throttle plate for reassembly.
-File/grind the throttle plate screws since they are peened to prevent backing out.
-Use an impact screwdriver (manual) to remove the screws on the throttle shaft and housing.
-purchase extra shaft seals in the event you damage any upon install.
-use thread locker and re-peen the throttle plate screws on reassembly.
-take the time to adjust everything properly.

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