Haltech Control of the A442f (5 Viewers)

[moremazda]

Long time lurker, first time poster here. I have a '94, non-locker bought it a couple years back. I'm looking to put together either an Elite 2500 or the 2000 to control the engine and transmission for a few reasons. I'd like to be able to tune the 1FZ to understand what the milage potential truly is, move to newer control electronics (the ECU's aren't get any younger)......and maybe turbo....maybe.

I am wanting to poke at the crowd for help trying to understand the control scheme of the A442f. The FSM does a complete job of describing the control of the two main shift solenoids and the lock up solenoid. It doesn't, however, talk about the timing solenoid.......at all......and there is no hydraulic schematic showing how the solenoids interact with the control valves.

Haltech has mapped the A34x but not the A442f. Looking notionally at the FSM for the A343f the "accumulator solenoid" may do the same thing as the timing solenoid.......so anyway that's the question I suppose, Does anyone know what the control scheme of the timing solenoid is? Does anyone have a hydraulic schematic of the A442F?

 

[Speedytech7]

Long time lurker, first time poster here. I have a '94, non-locker bought it a couple years back. I'm looking to put together either an Elite 2500 or the 2000 to control the engine and transmission for a few reasons. I'd like to be able to tune the 1FZ to understand what the milage potential truly is, move to newer control electronics (the ECU's aren't get any younger)......and maybe turbo....maybe.

I am wanting to poke at the crowd for help trying to understand the control scheme of the A442f. The FSM does a complete job of describing the control of the two main shift solenoids and the lock up solenoid. It doesn't, however, talk about the timing solenoid.......at all......and there is no hydraulic schematic showing how the solenoids interact with the control valves.

Haltech has mapped the A34x but not the A442f. Looking notionally at the FSM for the A343f the "accumulator solenoid" may do the same thing as the timing solenoid.......so anyway that's the question I suppose, Does anyone know what the control scheme of the timing solenoid is? Does anyone have a hydraulic schematic of the A442F?

Are we the same person, I just asked this haha

 

[moremazda]

Are we the same person, I just asked this haha

Haha yeah I clicked back to the forum after the post and saw yours like three or four down, hilarious

 

[ThreeEyedBandit]

Years ago I setup a 442F to manual electrically manual shift via the shifter. I used the shift solenoid matrix in the FSM, manual switch for OD and TC lockup. I did absolutely nothing with the timing solenoid, just left the wire disconnected. Still to this day it is working.

Not a real answer to your question, but some info. I am planning on doing the same as you, but with am 1FZ/A750 via a FuelTech ecu someday.

 

[Speedytech7]

Years ago I setup a 442F to manual electrically manual shift via the shifter. I used the shift solenoid matrix in the FSM, manual switch for OD and TC lockup. I did absolutely nothing with the timing solenoid, just left the wire disconnected. Still to this day it is working.

Not a real answer to your question, but some info. I am planning on doing the same as you, but with am 1FZ/A750 via a FuelTech ecu someday.

I like the sounds of this, if that is the case, and the timing solenoid isn't a requirement, more of a luxury so to speak that lets me put off playing with it until after I get the rest wired up and working. Thanks for the info!

 

[moremazda]

The troubleshooting guide basically lists the timing solenoid as contributor to harsh 1-2, 2-3 and 3-2.
@ThreeEyedBandit so you have it wired so the shifter position makes the electrical patterns of the two shift solenoids?

 

[ThreeEyedBandit]

The troubleshooting guide basically lists the timing solenoid as contributor to harsh 1-2, 2-3 and 3-2.
@ThreeEyedBandit so you have it wired so the shifter position makes the electrical patterns of the two shift solenoids?

Yup, that's what I did. L,2,D run 1st through 3rd and od switch clicks into OD, all electrically though the solenoids. Lockup is done through an extra switch.

 

[PIP]

Megasquirt controls the 442 fine. The timing solenoid is unnecessary.

 

[moremazda]

@PIP I have been all over the megasquirt forums (meaning I read the two or three theads that contained "a442f" in the topic) and there was nothing on that site that said "this is how I got my a442f working". Are you controlling your transmission with a megasquirt ? or know of thread where a functioning setup is detailed?

The solenoid is necessary for something, else you could remove it and the trans would work...... probably not the case. The designers would not have put it in place if it's function was purely arbitrary.

The way @ThreeEyedBandit is running theirs......without the hydraulic schematic.....is tough to say weather the manual mode is bypassing the function of the timing solenoid or the operation of the transmission is simply just tolerant to non operational solenoid.

 

[PIP]

@PIP I have been all over the megasquirt forums (meaning I read the two or three theads that contained "a442f" in the topic) and there was nothing on that site that said "this is how I got my a442f working". Are you controlling your transmission with a megasquirt ? or know of thread where a functioning setup is detailed?

The solenoid is necessary for something, else you could remove it and the trans would work...... probably not the case. The designers would not have put it in place if it's function was purely arbitrary.

The way @ThreeEyedBandit is running theirs......without the hydraulic schematic.....is tough to say weather the manual mode is bypassing the function of the timing solenoid or the operation of the transmission is simply just tolerant to non operational solenoid.

Yes, I have used megasquirts with 442 and 343 transmissions.

It is not detailed anywhere online I'm aware of.

If you want to find out just how important the timing solenoid is open your glovebox, pull out connector IH3 and cut the wire going to pin 3. Then go for a drive.

 

[ThreeEyedBandit]

I thought I read in some document that it was more of an accumulator to soften the shifts.

The way I did it is completely electric. I originally ran it in D using a rotary switch to select gears. Now it gets its inputs via the selector switch. I'll see if I can find the documents this evening

 

[moremazda]

I thought I read in some document that it was more of an accumulator to soften the shifts.

The way I did it is completely electric. I originally ran it in D using a rotary switch to select gears. Now it gets its inputs via the selector switch. I'll see if I can find the documents this evening

That's my suspicion right now, is that maybe it acts as a line pressure bleed when energized.

And I miss stated earlier the troubleshooting guide...... it is harsh engagement on the 2-3 and the 3-2, not the 1-2. But is engine braking in first gear.

 

[azngarage]

94s has separate ECU that control the transmission. Should it be easier to leave the transmission ecu in place and use Haltech ECU to control the engine.

 

[Speedytech7]

94s has separate ECU that control the transmission. Should it be easier to leave the transmission ecu in place and use Haltech ECU to control the engine.

Needs a ton of input from the stock computer to function properly unfortunately though.

 

[moremazda]

Yeah the stock TCU takes 3 or 4 inputs that are not defined out side of voltage measurements. Those 3-4 outputs could be used to drive the solenoids directly, since the logic of the TCU is defined in the FSM replacing the tcu is the same amount work setting up the standalone

 

[Speedytech7]

Yeah the stock TCU takes 3 or 4 inputs that are not defined out side of voltage measurements. Those 3-4 outputs could be used to drive the solenoids directly, since the logic of the TCU is defined in the FSM replacing the tcu is the same amount work setting up the standalone

I know the TPS is one, another is temp, and there is some cross computer communication, very primitive but the TCU tells the ECU it is time for a shift which make it retard timing for a smoother transition (easy to set up the same functionality with way less wiring with a haltech)

 

[PIP]

Yeah, the stock tcu works fine standalone. Iirc it just needs temp and tps analog signals.

 

[nickolai]

Compushift:

Toyota A442 Transmission Control with the COMPUSHIFT

Controlling the Toyota A442 Transmission with the COMPUSHIFT Sport transmission controller.

hgmelectronics.com

 

[ThreeEyedBandit]

Somewhere I have more info on the timing control solenoid, but of course can't find it. I'll keep digging but here is a tiny information

Diagnostics for the fun of it.

 

[PIP]

Compushift:

Toyota A442 Transmission Control with the COMPUSHIFT

Controlling the Toyota A442 Transmission with the COMPUSHIFT Sport transmission controller.

hgmelectronics.com

Highly not recommended.