4agze build questions

[ae86boy]

So I've tried the gen III throttle body on the car with poor results.

I had the J tube ported as per the instructions, swapped over the throttle cam, attached the tube adapter to the top, connected the afm, blocked off the abv as per instructions and plugged the s/c outlet side of the abv. Everything's sealed with flange sealant (what I've always used).

I cut off and plugged the three vacuum lines on the back, leaving the coolant lines and the idle intake tube on the front wide open.

Needless to say, it doesn't idle and runs like a box of rocks. Leaving the idle inlet open gives poor rough response, no idle. Sealing it off gave a smooth quick response but no idle.

Two thoughts: would puting the abv back on make this better? Do I need to run air from between the afm and the intake to the idle tube on the throttle body? I assume so, but am burned out and not thinking straight at the moment.

Thoughts?

[TERRA Operative]

Did you check that the idle control motor works in the right direction (you *may* have to swap the outer two of the three wires around).

Also, did you do this cutout to let the air through?




The installed TB. Notice the guide for the wire on the cam has been stretched open a bit to guide it better.




I then designed and got this adapter made up to provide a good, unrestricted inlet to the TB.

[ae86boy]

I've done everything you've listed except the idle control motor like I said in my post.

Now, because it isn't pictured, I assume that this is the 3 pronged yellow/grey/green plug next to the tube sticking out of the throttlebody in the first picture. How do I hook it up? What signal does it get that tells it to work? Is your tube not connected back to the intake strem through that black hose in the tb adapter picture?

[ae86boy]

Actually, I'm looking at the old mr2 throttle now...it has the same idle motor control...I never had it connected to anything either. It must default in the correct direction or not be a factor. I'm going to reconnect the abv and see if that fixes it...though I do believe ill wind up connecting that idle tube between the afm and tb before it works.

Thanks guys!

[ae86boy]

So, the idle tube didn't help much. All it really does is extend the time it takes for the car to stall by a few moments. Ill see if replacing the abv makes this better.

Any ideas how to wire the idle motor? Can I feed it constant 12v with the car on or something?

[PrettyCoolWagon]

Terra' Does that elbow narrow down to the new alloy adaptor or does is just look that way in the pic?

If so, curious as to the diameter of alloy intake pipe pre-elbow?

[TERRA Operative]

The silicon bend is 3" to 2.5" at the adapter.

The ABV motor is that green thingo you mention, it requires a pulsed signal from the ECU. If it's wired backwards, then it will close rather than open when it should, this may be the case depending on what vehicle the new TB is from and what it's going into, you just have to play with it and see. To swap the direction, you need to swap the outer wires around (leave the middle one alone). I used the motor from the new TB, and I didn't need to swap the wires, but YMMV.

[ae86boy]

It looks like I'm going to have to wire up something to the idle connector...it still won't idle.

Can I get away with connecting power and ground to the terminals to force it open all the time? I assume ground would be the center pin and power would go to either side to open/close it?

[TERRA Operative]

So you have nothing connected to the idle motor at all??

As I said in my last post, you cannot wire a power and ground directly to it, it needs a pulsed signal from the ECU. The only other way to do it is to use a different idle valve to bypass the throttle body entirely.

[ae86boy]

Right.

So, can I alter this idle valve to work in some way? Is there another tb that will give me this control like I had with the gen 1 unit before? It idled with no electrical connections. Should I go back to an ae86 4age tb and adjust it so its open just a tiny bit to maintain idle?

Does anyone know of any options or ideas that I have not considered?

Second question: this new tb has caused the car to run dramatically rich. Has anyone here swapped in a 5mg afm to increase airflow while decreasing door angle on the sensor?

[TERRA Operative]

A standard 4AGE throttle body uses a wax pellet ISCV which has no electrical connection and is the same size as the 3SGTE TB.

[ae86boy]

Did I miss something? I thought you said the 4age tb wouldn't work? Also, I've tried it and had the same results as you posted below...have you made it function since you posted this? Do you mean a different 4age tb?

If I can maintain idle w a 4agze tb with no electrics connected to it, but neither of the other two we're talking about, how is it maintaining idle?

You need a throttle body that allows ECU control of idle speed.

4AGZE and gen2 3STGE I have confirmed to work. I used a 4AGE throttle body, but I had issues with unstable idle and stalling too, hence I changed to a 3SGTE throttle body.

[TERRA Operative]

You need to be clearer with the way you have things setup. Why do you not have the wiring connected for the ISCV? You *NEED* it for the 3SGTE throttle body idle control to work. That is why yours does not work, it doesn't run on magic, it needs a signal from the ECU.
Just hook the three wires up as I've been saying and it will work.


The 4AGE throttle body will bolt up fine and will operate the cold start idle-up but will not react to any other engine loads (A/C, headlights, throttle transients, etc), so it's fine for track but sucks on the street (especially in summer, when it stalls every time the air con kicks in).

[ae86boy]

Okay...we're getting turned around here I think.

I have this 4agze engine running off the ae86 4age ecu, wiring etc. There's no where to plug in the ISCV...there's no signal to be had. No it doesn't run on magic...please don't be like that. I had assumed that because the previous 4agze throttle body idled just fine while having the ISCV disconnected, that this one would to. The 4age throttle body will not idle on the 4agze. I do not know why that is, but it does not. You said so yourself, above.

Do you have any idea why the 4agze throttle body would idle, but not the 3sgte one if they both "require" the ISCV? Is there another alternative that I have missed?

Secondly, does anyone know of a way to lean this thing out? This 3sgte throttle has caused the car to run very, very rich. I assume this is because the flap door on the airflow meter is maxing out well before it should due to air volumes. I was going to try and swap in a larger AFM off a supra to see if that would help. Funny, it didn't run rich off the 4age throttle...could it be some annomaly associated with the 3sgte throttle? I can't see that doing it, but I am unfamiliar with such things.

[nick.parker]

Do you have any idea why the 4agze throttle body would idle, but not the 3sgte one if they both "require" the ISCV? Is there another alternative that I have missed?

Some more stabs in the dark...IIRC 4AGZE has a idle bleed screw in addition to the solenoid and hot wax air valve device. Not sure about the 3S? Could it be an airflow is too little problem and the ECU is not able to 'understand' this scenario and compensate?

Also check the ECU for fault codes to see if its happy with the output of the 3SGTE TB at closed (idle). Maybe the ECU in some kind of limp home mode?


Cheers.