North American Turbocoupe Organization



Throttle body explosion
Asimov Offline
Senior Member
#1
Well, I guess the subject will catch attention anyway. Tongue

Making this a new thread here and tf, because the discussion has been spread out over several threads on both sites.

Been trying to get a view of a throttle body exploded before I disassembled mine, and nobody seems to have one. The gasket kit I got has, what appears to be, at least a decent one, so I thought I'd make it availible.
http://pics.l7.net/index.py/Photos/Examp...083-86.JPG

Part #12 on that diagram is, what I desperately hope, causing my vac leak. However, the actual leak is from the other end of the shaft (#22) as shown here:
http://pics.l7.net/index.py/Photos/Misc/...20leak.JPG

I hate taking things apart that I never have before, especially without good diagrams.


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-asi

1986 TC, 132k pretty well taken care of miles. k&n, [email protected], timing @ 8 (spout out), A/C delete. 3" Downpipe (no other exhaust... Whoever described that sound as a "pissed off tractor" hit the nail on the head)

[email pics to asimov at forced-induction org for sales/id/showoff purposes (free hosting)]

[This message has been edited by Asimov (edited 03-27-2005).]
-asi

1986 TC, 132k pretty well taken care of miles. k&n, [email protected], timing @ 12 (spout out), A/C delete. 3" Downpipe (no other exhaust... Whoever described that sound as a "pissed off tractor" hit the nail on the head)

[email pics to asimov at forced-induction org for sales/id/showoff purposes (free hosting)]
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Asimov Offline
Senior Member
#2
I don't understand how the throttle shaft is held inside the throttle body, or how it connects with the TPS.

In the image above of the exploded TB, it shows a "Seal, throttle control shaft" (#12) but that's on the TPS side, mine is leaking from the other side, where it shows the shaft (#22) going into the TB from the front (see the other url above if my explination doesn't make sense, it's circled.

Could somebody attempt to explain how the shaft is sealed into the TB on the side facing the front of the car?

------------------
-asi

1986 TC, 132k pretty well taken care of miles. k&n, [email protected], timing @ 8 (spout out), A/C delete. 3" Downpipe (no other exhaust... Whoever described that sound as a "pissed off tractor" hit the nail on the head)

[email pics to asimov at forced-induction org for sales/id/showoff purposes (free hosting)]


[This message has been edited by Asimov (edited 03-27-2005).]
-asi

1986 TC, 132k pretty well taken care of miles. k&n, [email protected], timing @ 12 (spout out), A/C delete. 3" Downpipe (no other exhaust... Whoever described that sound as a "pissed off tractor" hit the nail on the head)

[email pics to asimov at forced-induction org for sales/id/showoff purposes (free hosting)]
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fierospeeder Offline
Member
#3
i believe the bushings are acting as the seal.

The throttle "rod" is long and at the end is a notch. So the notch goes into the tps, just like a plug.
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Asimov Offline
Senior Member
#4
I discovered this leak while pressurizing the intake, so of course the motor was not running. As I rotated the throttle shaft to WOT, it progressively leaked more and more.

If it's the bushings themself, what are they made from? Are they removable?

The exploded view above only shows a bushing on the TPS side. An error in the explosion view, or is the front side different?

[This message has been edited by Asimov (edited 03-27-2005).]
-asi

1986 TC, 132k pretty well taken care of miles. k&n, [email protected], timing @ 12 (spout out), A/C delete. 3" Downpipe (no other exhaust... Whoever described that sound as a "pissed off tractor" hit the nail on the head)

[email pics to asimov at forced-induction org for sales/id/showoff purposes (free hosting)]
Reply

Asimov Offline
Senior Member
#5
grr, double post

[This message has been edited by Asimov (edited 03-27-2005).]
-asi

1986 TC, 132k pretty well taken care of miles. k&n, [email protected], timing @ 12 (spout out), A/C delete. 3" Downpipe (no other exhaust... Whoever described that sound as a "pissed off tractor" hit the nail on the head)

[email pics to asimov at forced-induction org for sales/id/showoff purposes (free hosting)]
Reply

fierospeeder Offline
Member
#6
bushings are suppose to be the cheaper version of ball bearings.

you can do a search on the web, but i think they are made out of bronze and have oil mixed in with it.


It has been a while since i took my throttle body apart. But in the pic, follow the throttle linkage, and you should see another bushing near the spring.


There are prob tolerances in the factory with the engineers. That the engine can leak so much vacuum. And they compensate for the throttle body leakage, PCV system, and evap. a motor never has 100% vacuum. But it does pull a lot of vacuum when the throttle is snapped shut.

It is normal for the throttle shafts to wear out. It is very common with carbs. Machine shops would just remove the bushings or replace it with sleeves. There might be a spec someplace where you can check it with a dial indicator on how much it can move.
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Pete D Offline
Administrator
#7
The shaft is held in place by virtue of the throttle plate being attached to it, by the two screws

The TPS end of the round throttle shaft is shaped like a screw driver blade on the end. The blade part fits into the TPS and turns it as the shaft turns.
Pete Dunham


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Asimov Offline
Senior Member
#8
Ok, I think I understand now. If the bushings are bronze, it shouldn't be hard to get some made at a local machine shop, I'll just take the parts down and let them mic it and get it right.

I can understand the engineers planning ahead for some vacuum leakage, but just to be honest, I'm absolutely astounded my car runs as good as it does with a leak that large. It seriously sounds.... well, something kinda hard to describe, but imagine drilling a 1/16" hole in a vacuum line, and maybe even a bit larger.

Am I going to need to unhook the battery for about 30 minutes and let the computer reset after I fix this, or will it learn on it's own as it's driven?

Yet another question: logic says that a leak into metered air under vacuum would make the mixture lean, and under boost would make it rich. Is my logic wrong here, does the computer figure it out on it's own and adjust, or have is it simply too small a leak to matter? If too small to matter, where would you draw the line and say it's too big?



------------------
-asi

1986 TC, 132k pretty well taken care of miles. k&n, [email protected], timing @ 8 (spout out), A/C delete. 3" Downpipe (no other exhaust... Whoever described that sound as a "pissed off tractor" hit the nail on the head)

[email pics to asimov at forced-induction org for sales/id/showoff purposes (free hosting)]
-asi

1986 TC, 132k pretty well taken care of miles. k&n, [email protected], timing @ 12 (spout out), A/C delete. 3" Downpipe (no other exhaust... Whoever described that sound as a "pissed off tractor" hit the nail on the head)

[email pics to asimov at forced-induction org for sales/id/showoff purposes (free hosting)]
Reply

GlassRooster Offline
Senior Member
#9
Asimov, I will email to you an expoded view later this week. My part wont be in until then so I wont be going to Ford. Hope you can wait, sorry but the stupid parts guy screwed up not me. Smart parts guy was off that day. Booo
David

87 TC Faded Burgundy with faded red interior
K&N and cold air ducting- rest is bone stock
02 Mazda Protege 5 Replaced Dead Saturn
99 Cougar- Wife's car new body style now Discontinued.
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Qwertys Offline
Senior Member
#10
typically bronze bushings are heat/pressure treated with oil so the oil seeps into the bronze. especially on systems without a constant flow of oil. at least, thats how it works on most electric fans.
'85 TC BPV and Ford FMIC
'88 TC Kirban AFPR, Autometer Boost, FP and A/R Gauge, 8.8 to 4.10 rear, Walboro 255lph Fuel pump, Garrett GT3071R T3/T4 Dual Ball bearing Turbo, Custom AWIC.
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