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1995 Camry V6 Throttle Opener

Does anyone know what the "throttle opener" on a 1995 Camry V6 automatic transmission 1MZFE engine does or how it works?

What I can see:

There is a vacuum diaphragm located underneath the throttle position sensor. The diaphragm is connected via a vacuum line to the throttle body. The diaphragm has a little piston sticking out f it. As the piston retracts, there is a contacting arm along the outer diameter of the throttle position sensor housing that, I guess, should turn. This arm seems to link via a shaft through the throttle body itself, and connects over to the other side, into the linkage where the throttle cable and shifter cable are attached.

I can't find anything on this in Haynes.

The thing I find odd, is that the contacting arm doesn't seem to turn a whole lot. The piston in the diaphragm will retract, and you'd think the contacting arm would follow it, but the arm travels about 1/8" or less and just stops. The piston in the diaphragm just keeps on retracting...

Is this normal behavior?

Thank you

Reply to
bensteadev
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The throttle opener is an emissions item. When the throttle is closed, the opener rod prevents the throttle from fully closing for a brief period of time. This allows additional air to completely burn the mixture reducing NC and CO emissions.

Testing. Engine at idle and warm. Idle speed 700rpm +/-. Disconnect and plug the end of vacuum hose. Idle should be at 900-1950rpm. Stop the engine and reconnect hose. Start engine, idle speed should be back to normal. If not, replace the opener.

Reply to
toyomoho

================== The Factory Service Manual includes an adjustment procedure for the "throttle opener" in the section on removing, replacing, cleaning and adjusting items associated with the throttle body. For the 1994 5S-FE engine, when I removed the throttle body, and replaced the IAC valve, I followed all the procedures for cleaning and adjusting. The TPS needed to be adjusted, the orofices for the EGR vacuum modulator lines needed to be cleaned and the throttle opener position needed to be adjusted. Basically everything they said to do needed doing. See:

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section under Fuel

Reply to
Daniel

Nice link, thank you!

When you pulled the IAC valve... did you have to re-set the throttle opener and re-set the TPS because it was necessary after pulling the throttle body (in other words, when you pull the throttle body, do you lose the settings)?

Or did you do it just to be thorough?

I was thinking of replacing the IAC valve, and it would be unfortunate if I were to pull the throttle body and lose a bunch of settings in the process.

Thank you

Reply to
bensteadev

Toyota put that opener in there after the problem with the throttle body cooling down and grabbing the throttle plate. And when people try to start up the car and wonder why they can't open the throttle.

The screw is adjusted so it opens the throttle sufficiently when the engine is off and doesn't interfere with anything when the engine is running.

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Reply to
johngdole

================================================ I did it just to be thorough. When I work on the car, I use the Factory Service Manual and follow each step. I do not believe removing the IAC valve had any effect - it is on the bottom of the throttle body and not really attached in a way that would affect anything else. For example, the TPS is adjusted with a continuity tester and a thickness gauge such that the continuity breaks off idle at something like .002" and mine was something like .004". A bit of dark colored goop sprouted out of one of the throttle body ferrules after applying carburetor cleaner and compressed air to the disassembled throttle body at the smallest of three openings in the top. And the throttle opener needed to have the plunger adjusted also. I don't remember the procedure any longer, but I do remember tightening the tiny locknut on the plunger, checking the adjustment, and then re setting it several times before finally ending up with the correct setting. I seem to remember looking at the tachometer as well. I think it was raise the rpms to 1500, release the throttle and then check the adjustment, but the book will tell you the exact procedure. I seemed to notice the throttle responding more smoothly afterward. Earlier, I had also adjusted the throttle cable by holding the pedal to the floor with a weight, and removing excess slack from the cable at WOT.

Reply to
Daniel

You don't have to reset anything if you pull the IAC valve, it's independent of TPS and throttle opener.

The notorious IAC valve, if need to be cleaned do not have to be replaced each time. Daniel uses Triflow spray after cleaning to keep it working, do a search on the post.

You will have to pull the throttle body to be able to work on the IAC more easily. Just don't spray throttle body cleaner into TPS or into the IAC's electrical side. Most cleaners attack rubbers and might cause seal problems.

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Reply to
johngdole

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