What's inside the 4AGE 16V TPS ??

User avatar
jondee86
Moderator
Posts: 2420
Joined: Fri Jan 11, 2013 10:21 pm
Location: Wellington, New Zealand

What's inside the 4AGE 16V TPS ??

Postby jondee86 » Thu Dec 20, 2018 11:58 pm

This is a question that I'm sure many people have asked themselves. But not
having a spare TPS to pull apart, most are destined to live out their lives without
ever achieving black-belt level in TPS knowledge. Never fear... help is at hand :)

Image

This is the throttlebody side of the TPS... what you see when you take it off.

Image

This is the other side with the plastic cover removed.

Image

The metal "wipers" that rotate with the throttle and run on the carbon tracks.

Image

And the carbon tracks that complete the circuits and provide resistance.

This particular TPS (89452-12050) came from an AE82 if I remember correctly, but
it is of the same era as the AW11 and AE86, so should be near enough the same. It
is not designed to be opened so therefore should be considered non-repairable. The
clips that hold the back cover on have to be broken to get the cover off. Under the
cover is a thin rubber diaphragm/sealing gasket, and below that the white board for
the carbon tracks. The board is gripped by clips that are part of the TPS output pins.

Cheers... jondee86
The reasonable man adapts himself to the world; the unreasonable one
persists in trying to adapt the world to himself. Therefore, all progress
depends on the unreasonable man.

Disable adblock

This site is supported by ads and donations.
If you see this text you are blocking our ads.
Please consider a Donation to support the site.


User avatar
Sprite
Club4AG Regular
Posts: 35
Joined: Sat Mar 19, 2016 5:23 am
Location: Twin cities, MN

Re: What's inside the 4AGE 16V TPS ??

Postby Sprite » Fri Dec 21, 2018 9:36 am

Interesting, I have wondered what was in there. I also wonder what makes one different from another for various engines. Is it simply the bolt and throttle fitting? And when they go bad is it just wear of the wiper tracks? They seem to cost more than they should. Anyway thanks for getting us to black-belt TPS level.
Rick

User avatar
jondee86
Moderator
Posts: 2420
Joined: Fri Jan 11, 2013 10:21 pm
Location: Wellington, New Zealand

Re: What's inside the 4AGE 16V TPS ??

Postby jondee86 » Fri Dec 21, 2018 4:19 pm

Toyota often use the same component under different part numbers on several
models. I see this particular TPS is also suited to certain Lexus cars as well as AW11
and Corollas. It is a key component in your car driving well, so it needs to be a
quality item. And the dealership network has to keep inventory available for the
expected lifetime of the vehicle (about 20 years IIRC), so they are gonna cost :(

But these days you can usually find a China made version on Ebay for cheap, or
grab a second hand one from somewhere, so no need to pay dealership prices if
you are on a budget.

While virtually all older TPS's have the same basic design, each car manufacturer
will have variations in housing design, plug, orientation with the throttle spindle,
resistance values etc. This helps to avoid installing the wrong TPS for the engine.
A late model TPS will usually have three pins instead of four (no IDL switch).

Because the TPS spends most of its life at the low throttle openings, the tracks
tend to wear out near the start of its sweep. They don't like water inside them
either. But apart from that they are a pretty reliable item and should be good for
200k plus miles of normal driving.

Cheers... jondee86
The reasonable man adapts himself to the world; the unreasonable one
persists in trying to adapt the world to himself. Therefore, all progress
depends on the unreasonable man.

oldae82
Club4AG Enthusiast
Posts: 97
Joined: Sun Apr 07, 2013 5:38 pm

Re: What's inside the 4AGE 16V TPS ??

Postby oldae82 » Sun Mar 31, 2019 2:41 pm

On my ae82 with the 4age, on and off low throttle is accompanied by a lurch, as best as I can describe it. It's either accelerating or closed throttle. I've adjusted the TPS by the service manual's resistance method, but I expect my adjustment is off a fraction. Any suggestions?

Disable adblock

This site is supported by ads and donations.
If you see this text you are blocking our ads.
Please consider a Donation to support the site.


User avatar
jondee86
Moderator
Posts: 2420
Joined: Fri Jan 11, 2013 10:21 pm
Location: Wellington, New Zealand

Re: What's inside the 4AGE 16V TPS ??

Postby jondee86 » Mon Apr 01, 2019 1:46 am

The transition of the engine from "idling" to "running" is controlled by the idle
(IDL) switch on a 4-wire TPS. The switching point is when the wipers just come
into contact with and bridge the two stubby tracks you can see in the above pics.

The switch should be closed when the throttle arm is on the stop or very close,
and open once the arm moves away by a small distance. Operation of the switch
can be confirmed by connecting your multimeter to the two appropriate pins on
the TPS. You are setting the switching point when you use the two different
feeler gauges between the throttle arm and the stop. The procedure is described
in the factory service manual.

Image
Generic image but you get the idea :)

While you have your multimeter out, you can also connect between the ground
signal pins and check how the resistance value changes as you move the throttle
arm. An analog meter makes this very easy as you are looking for a smooth
change in value from closed to open without any sharp jumps or dropouts. If you
find that there is a gap (dropout) right at the moment the throttle starts to come
off the stop then you are looking for a replacement TPS.

Cheers... jondee86
The reasonable man adapts himself to the world; the unreasonable one
persists in trying to adapt the world to himself. Therefore, all progress
depends on the unreasonable man.

oldae82
Club4AG Enthusiast
Posts: 97
Joined: Sun Apr 07, 2013 5:38 pm

Re: What's inside the 4AGE 16V TPS ??

Postby oldae82 » Mon Apr 01, 2019 5:49 pm

Thank you kindly.

Disable adblock

This site is supported by ads and donations.
If you see this text you are blocking our ads.
Please consider a Donation to support the site.



Return to “TECH: 4A-GE ENGINE”

Who is online

Users browsing this forum: No registered users and 2 guests