JDM User Manual in English?

[svxistentialist]

Joe, my car is a JDM import and has a power mode switch.

Regarding your suggested system, which i gather has not been tried in practice. Be sure that I do have a firm grip on what you have in mind.

I am sure you do understand well what is involved. Your first statement is incorrect. A guy in Jersey has tried this system and is using it in his car. With no problems

The TCU signal is used for several functions and its primary connection is to the ECU/MPFI unit. You are making assumptions regarding the timing and lock in circuitry which is very much speculative.

The assumptions regarding the timing and lock in circuitry are certainly speculative as they must be without reverse engineering the board, or having access to data on the original software and its purpose, none of which is available. They are however based on observed fact and as such are less speculative than your speculation that the timing of the shift map operation is controlled by the ECU.

Aside from that, any adulteration of the signal from the TPS, will surely affect the ECU.

The 5v feed can be taken from anywhere, but the obvious place at hand is the 5v feed to the TPS. The variable feed from the TPS to the ECU is not affected, and the diode is to ensure no reverse current flow in that direction that might adulterate the signal to the ECU

I would speculate that the timing/lock in circuitry/function is based at least in part, within the ECU. What is more, the power shift condition may not in fact be unlocked on the basis of time, as you predict.

I have to totally disagree with this statement Trevor. There is no reason why the TCU would not have enough computational power and enough signals to make it's own decisions on when gearchanges are required. If it required input or computation from the ECU, then turning on full-time Power as you can in your JDM would need to be something less simple than grounding pin 4, which is how your Power mode is activated.

It is possible that Power mode drops off because of some other parameter rather than time as you say. The supposition is based on what was observed, rather than what is known. In either case, for whatever reason it drops out, it is re-activated again by the fluctuating 5v WOT signal, and is not given time to drop out. End result, full-time Power mode.


Cheers, Trevor.

Trevor, I can only presume by what you are stating here that you did not read completely through the two suggested threads. Else you would have known that Mike in New Jersey had already used the system, and postulated the use of a 555 switch to interrupt the 5v signal. Also he observed Power mode dropping back after 5-10 seconds, which is similar to how it operates on the road.

You would also see where Phil had traced the circuitry in his car, and where I had substituted a JDM TCU into my English car, which also was not a success, but yielded information as to the nature of the transmission controllers.

I have copies of the USA TCU wiring in GIF format which I will send to you. Nobody has copies of the wiring diagrams that show the Power switch. These would only be available in the Japanese language Workshop Manuals, and nobody we know has one of these.

Joe

[Trevor]

Joe you said,

“This is provided by giving the TPS INPUT of the TCU a +5v signal with a timed interrupter in the circuit.”
Also, “This is done by using a diode in the line which lets this signal travel one way only. The ECU still needs to see the actual TPS signal to control the engine.”

Now I say,

I must have been asleep, read too quickly and WAS confused. I now hasten to apologise.

Edit P.S. Concisely, what you are saying, is that the when a signal at maximum voltage and in the form of a pulse, is received from the TPS by the TCU, it locks into power mode for a set time from when there is no further such signal. Therefore an imposed continuous repetition of such a signal will retain power mode.

OK, Trevor.

[b3lha]

Originally Posted by SURTEESS

So if the action happens inside the TCU then I guess their are 2 (or more) versions of the black box?

Trevor can you validate that pin 4 of TCU is the pin that I should check out?

Since I am a PCB designer, I have got the option to reverse layout the schematic for the JDM one that I hope to get this weekend, has anyone got a spare NON-JDM one that they can lend me to check over the differences - will post it back to you when finished - will also post what I find.

regards

Steve in Auckland.

Steve,

I compared my JDM TCU to pictures of Euro and USA ones - they all look identical to my untrained eyes. I reckon the difference is probably in the firmware. As PCBs are your area of expertise, would you be able to figure out how to download the firmware onto a PC for analysis?

Phil.

[Trevor]

Greetings Phil,

It does appear that there is more than one version of the TCU circuitry. Unfortunately as far as I am aware no one has a proper schematic covering TCU internals. The only way to sort out the difference would be to place the internals of both, one alongside the other and sort it out. I would expect at the minimum, a double sided board, or even more than one.

A computer can be of no assistance and I for one do not volunteer, for I am aware of the horrible job involved, having gone through this sort of procedure many times. What is more the existence of one or more strange unidentifiable IC's, will likely render the job impossible. Simply establishing the input/output circuitry may give clues, but this will require the application of in depth knowledge.

Cheers, Trevor.

[Trevor]

Joe,

Having now slept on the problem, I have another spanner to throw in. I presume all models have the traditional "kick down" feature as does mine, whereby flooring the throttle pedal, causes a chop down in the gears to provide maximum acceleration.

Surely this function must use the same signal, TPS/TCU, and therefore the add on suggested, would also cause activation of kick down.

Trevor.

[b3lha]

Originally Posted by Trevor

Greetings Phil,

It does appear that there is more than one version of the TCU circuitry. Unfortunately as far as I am aware no one has a proper schematic covering TCU internals. The only way to sort out the difference would be to place the internals of both, one alongside the other and sort it out. I would expect at the minimum, a double sided board, or even more than one.

A computer can be of no assistance and I for one do not volunteer, for I am aware of the horrible job involved, having gone through this sort of procedure many times. What is more the existence of one or more strange unidentifiable IC's, will likely render the job impossible. Simply establishing the input/output circuitry may give clues, but this will require the application of in depth knowledge.

Cheers, Trevor.

I understand what you are saying Trevor, but the presence of a cpu chip must surely indicate that at least some of the functions are controlled by a program stored in firmware? Such a program must read the input ports, process the information, and set the output ports to control the gearbox appropriately. I believe that if we were able to download and disassemble the program then we might gain some insight into how it all works.

[Trevor]

Originally Posted by b3lha

I understand what you are saying Trevor, but the presence of a cpu chip must surely indicate that at least some of the functions are controlled by a program stored in firmware? Such a program must read the input ports, process the information, and set the output ports to control the gearbox appropriately. I believe that if we were able to download and disassemble the program then we might gain some insight into how it all works.

Thanks Phil,

Steve reported that he was a PCB designer (Printed Circuit Board), so that I was presuming that what was in mind, was thus restricted. Yes you could very well extract information from the CPU chip, which could be helpful.

The ultimate of course,is to find out the respective differences and how the Power Mode switch is incorporated within the circuitry.

Cheers, Trevor.

[svxistentialist]

Originally Posted by Trevor

Joe you said,

“This is provided by giving the TPS INPUT of the TCU a +5v signal with a timed interrupter in the circuit.”
Also, “This is done by using a diode in the line which lets this signal travel one way only. The ECU still needs to see the actual TPS signal to control the engine.”

Now I say,

I must have been asleep, read too quickly and WAS confused. I now hasten to apologise.

Edit P.S. Concisely, what you are saying, is that the when a signal at maximum voltage and in the form of a pulse, is received from the TPS by the TCU, it locks into power mode for a set time from when there is no further such signal. Therefore an imposed continuous repetition of such a signal will retain power mode.

OK, Trevor.

Yes mate, this is exactly what I am saying.

You will remember early on in the thread I described it as a "trick", that fools the TCU into staying in Power mode?

Well, that is what it is really, a trick. It uses one of the inputs that the programme in the box reads to switch in the temporary on-demand Power mode shift map, and it repeats that signal so that the TCU circuitry leaves the car permanently working off that shift map.

In your JDM box, the Power switch merely grounds Pin 4, and that has the same effect, permanent Power shift map. It is a lot simpler to achieve, but only because the software in the Japanese TCU is set up to accept this signal, and act accordingly.

This raises an interesting possibility for our USA friends. The "trick" as I have outlined will switch on permanent Power mode, just like on JDM models. However, from the scans I have of the USA wiring diagrams for the gearbox, Pin 4 in the USA variant is not in use, no wire goes to that pin.

Assuming that the TCU connector still has the male Pin 4 protruding [why would it not? ] It would be interesting to see if some of our US buddies fed a wire to that pin, and grounded the wire through a switch. I suspect the USA transmission computer, because it uses the same external Hall Effect Speed Sensor 1 like the Japanese one, I suspect the software is already in their TCU to switch on permanent Power mode, without going to the rounds of wiring in the interrupter 555 switch and diode as per my "trick"

Anybody in the US up for trying that simple mod?

Joe

[b3lha]

Originally Posted by svxistentialist

This raises an interesting possibility for our USA friends. The "trick" as I have outlined will switch on permanent Power mode, just like on JDM models. However, from the scans I have of the USA wiring diagrams for the gearbox, Pin 4 in the USA variant is not in use, no wire goes to that pin.

Assuming that the TCU connector still has the male Pin 4 protruding [why would it not? ] It would be interesting to see if some of our US buddies fed a wire to that pin, and grounded the wire through a switch. I suspect the USA transmission computer, because it uses the same external Hall Effect Speed Sensor 1 like the Japanese one, I suspect the software is already in their TCU to switch on permanent Power mode, without going to the rounds of wiring in the interrupter 555 switch and diode as per my "trick"

Anybody in the US up for trying that simple mod?

Joe

I reckon it's worth a try but there was a distinct lack of interest when I prevously suggested it.

http://www.subaru-svx.net/forum/showthread.php?t=32489

[Trevor]

Originally Posted by Trevor

Joe,

Having now slept on the problem, I have another spanner to throw in. I presume all models have the traditional "kick down" feature as does mine, whereby flooring the throttle pedal, causes a chop down in the gears to provide maximum acceleration.

Surely this function must use the same signal, TPS/TCU, and therefore the add on suggested, would also cause activation of kick down.

Trevor.

Joe,

[svxistentialist]

Trevor, you sure you want to throw away your good spanner??

I have been sleeping on this too, and the short answer is I don't know.

Mike in New Jersey was doing the experimenting two years ago. Initially he was using a "blip" push-button circuit. This had the effect of momentarily switching in the "on-demand" Power mode. However, he did say when he held it on, the gearbox went crazy, by which I'm sure he meant kickdown was activated.

Now he replied later in another thread that he had made it work using the 555 interrupter switch, and I took his word on it.

However, I am not sure if "made it work" means Power mode switched on, gearbox usable, or Power mode switched on, plus kickdown activated.

So I have sent him a question to clarify this via the old thread. We will wait on his reply before we recommend the mod.

Joe

[I'm not able to implement this on my car just yet till I get the new gearbox in, otherwise I would guinea pig it myself.]

[Trevor]

Originally Posted by svxistentialist

Trevor, you sure you want to throw away your good spanner??

I have been sleeping on this too, and the short answer is I don't know.

Mike in New Jersey was doing the experimenting two years ago. Initially he was using a "blip" push-button circuit. This had the effect of momentarily switching in the "on-demand" Power mode. However, he did say when he held it on, the gearbox went crazy, by which I'm sure he meant kickdown was activated.

Now he replied later in another thread that he had made it work using the 555 interrupter switch, and I took his word on it.

However, I am not sure if "made it work" means Power mode switched on, gearbox usable, or Power mode switched on, plus kickdown activated.

So I have sent him a question to clarify this via the old thread. We will wait on his reply before we recommend the mod.

Joe

[I'm not able to implement this on my car just yet till I get the new gearbox in, otherwise I would guinea pig it myself.]

Joe, Your previous advice indicates that the modification is your idea, has been done and WILL work. Others could already therefore have started moving on this. I have had, and still have doubts.

[svxistentialist]

Originally Posted by Trevor

Joe, Your previous advice indicates that the modification is your idea, has been done and WILL work. Others could already therefore have started moving on this. I have had, and still have doubts.

Previous advice from 31-8-06:
<<<
LAST AND IMPORTANT POINT!!!!

I am volunteering this information with no guarantee or warranty. Anybody tries this, and smokes their ECU or TCU or any other damage caused by these modifications, you must be assured you know what you are doing, and that I will not be responsible if it goes wrong.


I'm going to do my own car like this. If you want to wait a few weeks until I have time to hunt up the switch and have time to do it, I'm willing to be the guinea pig and take a few jpegs as I go.
>>>

has been done and will work:

<<<
However, what you can do which DOES work is pulse +5V to the TPS input on the TCU with a 555 timer. I gaurentee that will work 100%.

Here was my original post: http://www.subaru-svx.net/forum/showthread.php?t=20197
__________________
>>>
From Mike in New Jersey 01-09-06

Others could already therefore have started moving on this. I have had, and still have doubts.
<<<
I reckon it's worth a try but there was a distinct lack of interest when I prevously suggested it.

http://www.subaru-svx.net/forum/showthread.php?t=32489
>>>
From Phil, 5-4-06

There does not seem to have been a rush of people trying these mods. This simpler suggestion for those with American TCUs did not even get a lukewarm reply or one person willing to try installing and grounding a wire.

So if there is somebody has started moving on this, I for one don't know who they are, and they might have the courtesy to advise the forum of what they are trying and what is the outcome of the attempt.

No written information exists about how Power mode is activated in the Japanese TCU set-up. So these "tricks" are experimental, Trevor. The risk-takers are the ones taking the trouble to think through the process, and putting their time, expertise, hardware and experience at risk for the benefit of others who may not even take the trouble to read thoroughly through previous attempts to modify the control systems.

Caveat experimentor is a phrase that jumps to mind. If you can't afford to lose it, then don't bet it.

And don't drink the snake-oil.

[Trevor]

Hi joe,

Although a wiring diagram which does not show relay contacts is shown in the thread and there is no proper schematic,, it seems certain that a change over contact is used to transfer the TCU from the TPS to a 4 volt unregulated supply. This is quite different from the arrangement you have suggested incorporating a blocking diode. Relay switching would isolate the TPS, but the applied voltage could still be read by the TCU as a “kick down” signal.

I now read this from the linked thread :-

“If you hold down the button the TCU thinks you're flooring the car (WOT). So, it'll downshift to the lowest possible gear, (Is this not kIck down ?????) meanwhile the butterfly is barely opened. Because of this the engine is putting out a lot of effort,(?????? torque ???) and the trans will suddenly upshift into it's normal gear. There's no point to hold the button down anyway. This is just for a change in shift points ...that's all, you won't feel like an instant power boost simply by hitting the button because you're not feeding any more air into the engine. It's still fun to have it shift at 3k under mild acceleration rather than 2k.”

The text is confusing to say the least particularly, ----- “ It's still fun to have it shift at 3k under mild acceleration rather than 2k."
Is he in fact referring to kick down and the shift referred to is in fact a down shift ?????

Basis on my understanding of the proposal, as well as the existing functions, including my concerns regarding kick down, I remain sceptical.

It will be interesting to see what your further enquiry brings forth.

Cheers, Trevor.

[svxistentialist]

Originally Posted by Trevor

Hi joe,

Although a wiring diagram which does not show relay contacts is shown in the thread and there is no proper schematic,, it seems certain that a change over contact is used to transfer the TCU from the TPS to a 4 volt unregulated supply. This is quite different from the arrangement you have suggested incorporating a blocking diode. Relay switching would isolate the TPS, but the applied voltage could still be read by the TCU as a “kick down” signal.

I now read this from the linked thread :-

“If you hold down the button the TCU thinks you're flooring the car (WOT). So, it'll downshift to the lowest possible gear, (Is this not kIck down ?????) meanwhile the butterfly is barely opened. Because of this the engine is putting out a lot of effort,(?????? torque ???) and the trans will suddenly upshift into it's normal gear. There's no point to hold the button down anyway. This is just for a change in shift points ...that's all, you won't feel like an instant power boost simply by hitting the button because you're not feeding any more air into the engine. It's still fun to have it shift at 3k under mild acceleration rather than 2k.”

The text is confusing to say the least particularly, ----- “ It's still fun to have it shift at 3k under mild acceleration rather than 2k."
Is he in fact referring to kick down and the shift referred to is in fact a down shift ?????

Basis on my understanding of the proposal, as well as the existing functions, including my concerns regarding kick down, I remain sceptical.

It will be interesting to see what your further enquiry brings forth.

Cheers, Trevor.

Yeah, Trevor, you are quoting the bit I mentioned in a post two or three back.

I'm not sure. I'm still waiting on Mike to reply, see what exactly he managed to trigger, good or bad.

Triggering Power mode PLUS kickdown might be a marginal benefit for what Americans call "track" use, the drag strip. It would not be street usable, and so not worth the effort for most.

Like you, I see difficulty in forcing Power mode through the tps input pin, without simultaneously effecting kickdown. Hence my joke about your spanner in the works.

Thanks for keeping a sceptical eye about these electrical mods Trevor. Whatever we do manage to achieve from testing the systems will be a joint effort of collaboration between all the people who contribute ideas and suggestions down through the years.

And of course put their money where their mouth is, and TRY things out.

Joe