2UZ hybrid Throttle body to full cable (1 Viewer)

[woytovich]

NOTE: So I changed the thread title to reflect where this thread has gone.
It started out with a simple question about the connectors below... the intent the whole time was to convert the early 2UZ TB from hybrid (cable actuated but mostly electronic) into a full direct cable actuation. Follow along as I see if this is going to work...
Disclaimer: this is part of a project to stuff a 2UZ into a FJ45LV using a Spitronics Mercury2 ECU and harness, thus the need to ditch the hybrid system, but also in order to regain what I hope will be better pedal to TB response.


What are the 2 grey electrical connectors shown in this pic?
Thanks...

 

[badlander]

That is the idle air control motor on the end where the plugs are located. One connector would be for that. Not sure what the other is for. My best guess is a throttle position sensor or temp sensor.

 

[87warrior]

• Throttle Position Sensor
• Throttle Motor

The Throttle Motor is what opens the butterfly. The cable only actuates the Accelerator Pedal Position Sensor, not the butterfly. The cable will open the butterfly a little bit if the pedal is wide open if the Throttle Motor or APPS malfunctions.

 

[woytovich]

THANK YOU 87warrior and badlander...

And what is this plug on the cable side? (on the TB, not in my hand)

 

[Zjohnsonua]

That black mechanism is the pedal position sensor that @87warrior mentioned. The name screws with you because while it directly measures the pedal position, it isn't by the pedal.

This throttle control is a pretty slick mechanism. I've long wondered why they bailed on the mechanical fail-safe.

 

[woytovich]

Pedal position vs throttle position? What is the pedal position sensor use/function?

 

[woytovich]

3 plugs are being discussed.
Black on on cable side...
2 grey ones on motorside...

 

[Zjohnsonua]

Yup, it's a little odd. Black is pedal position. The ECU uses this to determine how far to open the throttle blade. One of the gray ones is motor power. The other is throttle position. Throttle position creates the feedback loop to let the ECU know the throttle blade is in the correct position relative to the pedal demand.

There are some subtle advantages to this control architecture over a pure cable throttle, otherwise yeah, they could've simplified the heck out of this and just used a cable throttle like every other OEM. IIRC these UZ variants don't have an IAC valve- because the engine is controlling the throttle plate all the time.

 

[woytovich]

So:
Pedal Position Sensor detects how far the pedal is pushed (via the cable)
(Cable only turns the spring loaded piece that feeds the pedal position sensor)
ECU reads the PPS and tells the butterly how far to open via the throttle motor
and the TPS tells the ECU how far the butterfly is open

Do I have that right?

How is that then better/different than the fully electronic throttle body in function? There is no direct connection between the pedal and the butterfly in either case...?

 

[Zjohnsonua]

Yup. That's correct. The only addition is that the pedal can mechanically open the throttle blade at the end of the pedal travel. IIRC the pedal will engage the blade at ~85%. This lets the driver have at most 15% throttle in limp mode. IMO, fully electronic engines are a step back in that regard.

 

[woytovich]

Thanks...

 

[woytovich]

Has anyone here modified this semi electronic (hybrid) TB to be fully manual? Cable direct all the time?

 

[Zjohnsonua]

What's the goal in doing so?

 

[woytovich]

I'm working on a 2uz swap into my fj45lv and I am hoping to simplify the electronics. Plus having fully manual control over the butterfly might increase reliability and decrease complexity of the overall system.

 

[Zjohnsonua]

Nice! I'm swapping one as well, into my 60. I can appreciate trying to simplify that harness, but I think you'll be inviting more gremlins than you want. A big one would be maintaining idle since there would be no ECU-controlled IAC function in place.

 

[woytovich]

I am using a Spitronics ECU: "The throttle has a mechanical stop screw which you will use for the idle rpm, with fuel and timing compensations in the ecu software you will be able to make it idle."

You can see the screw that holds the butterfly open enough for idle:

I'm fabbing up an adapter ring to clock the cable mechanism thingy to the position where the lever will be just touching the butterfly's lever. This should mean that the butterfly will move right away as the pedal is pushed rather than waiting for nearly full throttle.

Clocked position:

Original position:

I may also try to find a way to detach the motor from the butterfly although with no power it does not seem to offer any resistance or other complications. The TPS will still function as necessary.

 

[woytovich]

This is a VERY basic proof of concept cut out of thin aluminum.... but it works! Final will be steel, possibly tapped rather than nut/bolt for the clocked spring piece, and some spacers added where you see threads on the shiny hardware.
I'll also likely have to mess with the cable routing/brackets to get the cable to pull at the right angle for full 0-100% throttle.

 

[abuck99]

Cool thread

 

[Zjohnsonua]

I'm very interested in seeing where this project goes.

 

[Eicca]

Very interesting. My 1UZ has the same system, and I read about some LS400 guys taking the same approach a while back. The trouble they ran into was the clutch from the butterfly motor trying to manipulate the butterfly in opposition to the cable. They say it resulted in anything from a stiff pedal to error codes.

But you’re using an aftermarket ECU so you should be able to bypass those issues.