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1990 Throttle Body Seal replacement

You may follow this for other years however some steps are different, for any other year I suggest following one of these two vfaqs, it would also be helpful to refer to these for the 90 as well, however neither are 90 specific.

For those of us who own 90's we know there are many differences in the 90 dsms compared to the 91-94 versions. One such difference is the throttle body. As far as other technical differences they can be discussed elsewhere, the key here is the seals. When doing a boost leak test, if you can hear leaks around the throttle body, try turning the throttle by hand, if the sound of the leaking air changes you can bet your seals are worn out (this goes for any year dsm). Unfortunately the seals for the T/B are no longer carried by most dsm parts manufacturers. I am unsure as to whether or not you can get them through the dealership but if all else fails try them. A better solution to the stock seals is to order some new stronger seals made by Chicago Rawhide. The actual seals I purchased were made for Chicago Rawhide by SKF Seals. For a dealer in your area follow this link and chose the FIND DISTRIBUTOR button at the top of the page. Type in your zip code and they should be able to find you a dealer in your area who can order the seals in, expect to pay around 15 for the set.
For the 1990 TB's you will need one part #3030 and one #3930, if you have a 91-94 you will need two #3930.

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These seals are metal encased in rubber, they will not wear out like the old stock seals, this should be a permanent solution.

EDIT: 92 GSR-4 has another solution for the seals if you can't get them from ChicagoRawhide. INA also carries these seals which should be available through You can get them under part number:
G10X14X3 (which is the larger seal which you will need two for the 91-94 TB and one for the 90)
and for the 90' Tbody's smaller seal:
They are identical seals. Even the little numbers printed on them are the same.
The last page has a pic of these seals!

Now Start by removing the TB from the car, if you don't know how to do this follow the first VFAQ link above as it explains removing the TB in the first half.
Now mark your TPS so you can replace it in the exact position it was before, if you do not do this step you will need to reset your TPS by following this vfaq I have no idea if this the same way to configure a 90 TPS but I would assume it is very similar.
Here is how I marked my TPS to make sure the screws sat in exactly the same place when i put the TPS back on. I used a silver sharpie.

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Now you can remove those two screws safely. Make sure you set them somewhere where you won't lose them.
Now turn the throttle body around and look at the other side, you will want to mark the spring so that when you re-install it you have it at the right tension. I used a black sharpie to make a straight line, when wound tight it will be straight again.

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Now carefully remove the end nut with a 10mm socket, set the nut and the washer off to that same spot you set the TPS screws. Now VERY VERY carefully remove the throttle plate wheel, the springs will want to unwind themselves very quickly and it can be painful if they catch you. If it didn't fly off then pull the springs and white (thing?) off.

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Now you want to mark the throttle plate so when you re-install it you can put it in the correct way. Mark one end such as this

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This where it can get scary, make sure you have the right size philips screwdriver tip to remove these screws, they are easily stripped. I found it best to place alot of downward pressure in order to keep from stripping the screw heads.

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You should then be able to rotate the shaft and pull the throttle plate out, for mine it took a little muscle, however they normally slide out quite easily.

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On your 90 you will need to remove a small rubber seal, a plastic washer, and a C clip (C or E, I forget what they call them) from the front side of the TB. You can see the C clip in this picture

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And now the clip having been removed, also note the metal washer behind the clip.

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Do not lose these little parts as you will need them when you go back to re-install.

Now you should be able to pull the shaft out.
EDIT: according to Eclipsh he noticed on his TB shaft that after removing the screws in the TB plate there was a ridge around the side where the screw ends had been crushed. He had to machine these ridges down before pulling the tb shaft so He didn't score the channel. Although I didn't notice these ridges on mine it may be something to look out for. Thanks Eclipsh!
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Clean it up with a non abrasive cloth or paper towel.
Now using the blunt end of a screwdriver pry the old seals out of both ends.

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This is what my old seals looked like, hardly and rubber left on them

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Use some dielectric grease and lube up the new seals and the ends of the shaft. Dont worry about using a lot as this will only help. Then press the new seals into the TB, I used the end of my ratchet to push them in, again the more grease the better.

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Now you can begin the process of putting everything back together. Push the rod back into the TB and on your 90 place the metal washer on the end and then the C clip, overtop of that the plastic washer and the tiny rubber seal. Then put the throttle plate back in (make sure you put it back in the right way as marked) and put the screws back in. It is recommended to use new screws 4mm x .75 with a 10mm length. Use locktite as if these screws came out they would go straight through your intake and.....well you can imagine the terror they would cause. Now test out the action, does it move in the correct direction? Does the plate line up correctly? On your 90 it may stick in the fully closed position, this is ok as when you tighten the nut on the other end of the shaft it will pull everything tight and keep it from sticking (had me freaking out for about 10 minutes, don't want anyone else to worry)

On the other end put the springs and the white (thing?) back on and wind the springs (I used a regular screwdriver) until the lines are straight again, place the throttle plate wheel back on the end of the rod and hook the springs around the proper end piece. Place the washer and thread the nut back on the end of the rod, tighten it firmly but not too strong, you can strip the threads very easily. NOw check the action, does it snap back into place like it did before? Does it stick when it snaps closed and you try to open it again? If everything checks out fine move on to the TPS. Make sure you have the little rubber seal that goes on the inside end of it and place it back on the end of the rod. Line your screws up according to your marks and tighten them on down.
Guess what, your ready to reinstall it in your vehicle and do another boost leak test! The gaskets in between the TB elbow and the intake manifold are known to be great places for leaks as well. I suggest using some copper rtv silicone as well to get a good seal. I have also heard of others using some rubber sheets from Home depot to make new gaskets and those work wonders as well. Happy boosting!

Alternative seals from INS which you can obtain through

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