I'll also put in that the JDM throttle bodies are slightly different - very minor things. The big one is the primary throttle stop, it's an easily adjustable screw with a spring between in and the TB. The US TB's use a small set screw with a nut around it.

Also, the TB with the fast idle cam disengaged should have all throttle plates shut. If you put a bright light on the other side you shouldn't see any light around the throttle plates. If so, the stops need to be adjusted. If there is a gap you'll have a high idle.

Dale

If ya run across some photos, stick them in here for further reference. I’ve only seen one Tb with the primary set screw having a compression spring. That would make adjustment easier.

Interesting that you mention that. There is an actual primary butterfly degree that you set initially. I’ve seen it floating around the forum but can’t place it at the moment. I can tell you’ve been in this a long time because the flashlight trick is an old-school thing. One that I still use. When making initial adjustments on the primary and secondary butterflies, you want the stop screws to just make contact with the stop arm. I “think” you make one half turn from fully closed to start Initially. Also, it’s a good idea to put a spacer ( I use two nickels ) between the fast idle cam adjuster screw and the thermo plate. This way you won’t have it opening the primary butterfly slightly as it does for cold start operation.

ps~ thanks for your insight, I quite enjoy reading your write ups also. They’ve help me out over the years.

~ GW

Can anybody reference where i can get these quad rings and what size / part number they are?

It’s the first picture in the thread.


~ GW

that part number works, i bought some ~3 months ago. my throttle body is like a colander lol

That was one of the reasons I started this thread. I really disliked that you’d see these gorgeous engine days that had been completely redone, upper intake manifold and piping coated / polished but the tb was just the same old dilapidated piece. Kind of an eyesore really.


~ GW

thanks thats what i get for using the copy text from photo on iphone (didnt copy right)

good write up and thanks!

i just rebuilt my throttle body, and even with the Vessel screw driver i managed to strip one throttle plate screw, and mangle a couple of others. these screws are 4mm x 0.7 x 9mm long. its a common size, i think 8mm long screws would be flush with the end of the shaft, which should be a couple CFM better flowing, but the store had 10mm screws, so i have 10mm screws....

other than that its all good news!
GDubs pics are great, i took my own, but used his
second, except for the TPS, none of the adjustments get touched.
third, if you only wanted to change seals, the shafts can come out without taking everything apart, although it is nice to clean/grease all the moving parts
four, the secondary throttle plates have a 7 on them, so its easy to put them back in the right orientation (they aren't cylinders, there is a bevel), the primary throttle does not, so a little mark is a good idea, saves a little time messing with it
five, there is a coating on the back of the throttle plates and around the place where they seat, and its somewhere between a sealant and a paint, but its there to seal any little leaks. IMO its a good idea to leave it there. or even put it back
six, i think this took me about 4 hours, it is a carburetor with no float bowl.
seven: if you have a stock ECU and need to set the TPS, i've found that safety pins work great for this, the pin goes in the ECU connector, and the safety part holds the voltmeter probe, win win

I found that some of the really corroded tb’s I had rebuilt were really stubborn hardware. I gave them ( screws / linkage ) a shot of pb blaster, put the heat gun on them till they got hot to the touch ( you don’t wanna use a torch because it will get excessively hot / soldering iron takes too long ) and used a Milwaukee m12 impact driver with a jis tip. If I tried to use a screwdriver by hand it would booger up the heads some. With the impact and moderate down pressure I find they come right out perfect.

If you stripped a butterfly screw thread on the round plate bar it’s self, it’s salvageable. There’s actually enough meat to tap it to the next size. I’ll have to look at what the next size is but it may be standard like 3/16 or 13/64. Something in between before you get to 6mm. For the overall length, and easy trick is to spin a nut down on the screw and cut / grind off the excess. Then spin the nut back off to clean up the threads. Those screws are LITTLE. Also annoyingly short. I may have an extra bar and or screws, I’d have to look.


~ GW

Can a leaking throttle body cause a boost leak?

Sure can. Your best bet is to smoke test it first.

~ GW

I did smoke test it. It’s definitely leaking but could it limit my primary turbo to 2psi? And not my second turbo?

Doubtful. That’s going to be in either the mechanical or electrical turbo control. Without derailing this thread, you should go thru the fms and run down the checklist like suggested in your other thread.

~ GW

Nah, my FC'sthrottle body had slight leak out the shaft seals and it had no issues holding 30psi boost.

You have to view boost leaks on how many cfm they are flowing. A boost leak limiting you to 2psi would be something you can stick a finger or two in.

I wanted to update this thread with some pertinent information. I’ve had a number of pm’s asking if I would be interested in refurbishing tb’s. Though I am still not interested in doing that, the guys over at @JP3 Motorsports are now offering this service. I am not affiliated with them but wanted to pass the information along. At this time they are the only ones offering this service which appears to be top notch, just like the rest of their offerings.

~ GW

Link >
https://vaporhone.com/throttle-body-restoration

just for fun, i found a stock throttle body with the thermowax adjusted at the last line opens the throttle about 0.040" or 1mm.
so if you put your feeler gauge between the throttle stop it should be about there.

I learned if you do not know where to initially set the fast idle cam, there’s a trick. With the car cold or the tb by its self, adjust screw “B” which is the amount the primary butterfly opens to the correct temp on the corresponding dash mark. Then take two pennies and slip them between adjustment screw “A” and the wax rod. Adjust screw “A” until the primary throttle plate just starts to crack. This gets you in the ballpark for opening angle and duration. You adjust from there by adjusting screw “B” clockwise for higher rpm and screw “A” clockwise to reduce the duration or to lower the coolant temp it disconnects at. Also, the amount of cold start up timing reduction you have will change the rpm. You just have to play with it over a few sessions to get it dialed in.


~ GW


https://cimg4.ibsrv.net/gimg/www.rx7...90b2a3fd2.jpeg

He
https://cimg0.ibsrv.net/gimg/www.rx7...182d345a9.jpeg
Heres my finished throttle body.