Paul Booth

Oh thanks Phil. That gives me loads to look forward to

I'll get it translated when mine arrives (Japanese friends)

Hopefully, you will find the lack of boost is a hose (sounds like it). I'm fitting mine (hopefully) either next week-end or the week after. I'll try to look for an elegant solution which stops the flashing lights without butchering the wiring loom or removing bulbs.

Was this just after you fitted the HKS TRC removal by any chance?

Do you have this problem when you first switch on the ignition or after you've started the engine/moving? All the circuits are self testing so just disconnecting them is always going to upset it. You have to either leave the circuits electrically correct or take the bulbs out.

Bring your own straight jacket :biggrin:

Why not just plug in a modem, run Hyperlink and send "ATD'your mobile number'^M" If it rings, the serial port's working and you've an MS-DOS issue.

No way Jose. I know they *can* be removed; I've never seen it done but I know it's a *very, VERY* difficult job.

Yes they do translate tro miles. My conclusion exactly, i.e. UK odo fed with a sig-gen. I assume you've looked at the odo; you'd have to pay me a lot to want to swap that rather large quad flat pack sitting under the CCF display panel, with likely lifting pads during seperation. It's just not worth the labour costs. No thanks, UK odo and sig-gen for me, thank you very much.

Whatever. You might be right that they have the divide link on the back of the odo swapped, I just remember they referred to the cost of 'buying' the units and having them converted, which I assumed at the time to be 'clocked'. The effect is the same as far as the loom wiring and pulse shaping is concerned.

The JIC converter feeds an 8/5 pulse train into the speedo but they then use a UK odo which already handles the miles v Km issue. Then, to get around the speed limit issue, they cut the square pulse signal output from the back of the odo and feed that with a limited signal from the converter, output 2. Now I have yet to determine whether it is frequency limited, i.e. it delivers an accurate input/output response up to the limiting figure and then caps it off at that point, or whether it uses the same 8/5 pulse train. The problem with this is that you're not providing accurate data to the PPS, etc.. There's an argument (which I'm inclined to buy into) which says beyond 112 mph the characteristics of the PPS, A/C amplifier, Cruise control, etc. are irrelevant anyway. Now if I *was* correct, why would HKS do an SLD device for the manual and one for the auto. This leads me to believe that the JIC solution is probably perfect for manual boxes but there are hidden issues on the auto. Therefore, I will go with the safest route, i.e. use the JIC converter for the speedo but leave the square pulse output from the odo driving down to the Engine ECU where I will fit the HKS SLD. Hopefully, once I've seen where that wires into on the auto it will give me the necessary clues as to what's going on with the TRC. I feel confident removing the butterfly and braking components of the TRC immediately as (a) It's a waste of space & (b) by leaving the electronic interaction between the TRC ECU and the engine ECU in place, you ensure any timing/EFI function exist during up-changes. The flashing light referred to on the US site will be bacause the sub-throttle actuator has a position sense feedback and if it doesn't 'see' any movement it will report an error code. I'm going to look at mechanically connecting the actuator to the sensor when I remove the butterfly.

Ash, I *know* where code 42 is coming from. It's the output from the pulse shaper in the odo. The Pink wire isn't making with the back of the odo properly and, contrary to popular belief, you can't just link the wire from Sensor No 1 straight to the Engine ECU, PPS, Cruise, etc. as the signal needs pulse shaping (i.e. squaring off) via the odo first. If I'm absolutely forced into it, I can solder the wire directly to the odo, but I'm gonna be real desperate for that to happen. The ECT uses Sensor no 2 for it's speed data and Sensor no 1 is only a 'back-up'. It's a very intermittent fault anyway, so I'm going to look at tightening up the female pin in the odo connector this p.m.. This is a minor problem and unrelated to my previous performace issues.

Oh yes, and BTW, my TRC is out of there, as soon as I can get the HKS kit.

It's the one covering chassis, electrics, brakes, ECT, etc. I didn't look to see if the engine was in there when I was "getting out before they change their mind". No I have to go back to see if I can pirate an engine one.

What we know so far....... Well...... I spent until 01:30 last night reading "The Good Book" and from what I understand: Hitting the disable button simply hits the TRC ECU with a momentary earth to signal user intervention. I too surmise this only prevents it applying any action under slip conditions although this is logical surmise, not stated fact. TRC is only active during up-changes, NOT down-changes. This much is stated. This does not agree with the evidence, as I have proved, supported by a third party, that gear changes are smoother, down *definitely* with TRC disabled. The fault diagnostic chart for lumpy gear changes includes the TRC ECU as part of the fault finding. The TRC is slave to the Engine ECU and is linked in with the EFI function. There is no differentiation between j-spec and uk-spec in the book and it includes a hydraulic pump in the functional description for *all* JZA80 models. Again, surmise, it appears all activity but the sub-throttle butterfly and braking are controlled by the Engine and ECT ECUs and, other than under slip condition when the TRC is considered part of the brake curcuit, the TRC is the slave controller for the sub-throttle. Incidentally, the Engine ECu could perform the same function using the main throttle, so why doesn't it. In the fraction of a second that the ECT changes up, any action by the sub-throttle is going to be way too late and this appears to me to be similar to the slip function, too little - too late and pointless. Let's face it people while their hardware engineering is first rate, I have personal experience to support the fact that the Japnese are CRAP at software solutions. If Leon is burning clutch packs, I think this is down to power applied and not throttle control. To reiterate, my car changes down demonstrably more smoothly with TRC disabled and this flies in the face of the the book. I didn't think to pirate an engine repair manual (but it's on my list) so I'm hoping Ash has one and we can tie the action of the sub-throttle and the EFI/timing to ECT up-changes.

Well this did have oily hand prints on the outside cover which I had to remove with Flash, it's not brand spanking new; OK the pages are perfect ("we don't see many Supras y'know" ). One reason I was able to acquire it is that they normally only keep one per model and, for some reason they didn't understand, they had more than one for the Supra. Apparently, this book normally costs £150 (according to auto-electrician) but I thought he was BS'ing me. Much as I'd like to acquire a wheel-barrow full, even if they had them, it would be an abuse of a friendship, and I don't do that deliberately, sorry (by accident sometimes, only human) .

Spent most of the day in the car, popping here and there, with TRAC on and off. Took chum (body-shop-man) along for objective assessment. He agrees, much, *much* smoother changes with TRAC off. Also noticed a new problem: Overdrive OFF lamp flashing on/off. Using his influence within his organisation, we took the car into the Toyota main agent to let them plug their diagnostic tool in. Code 42, which basically means I haven't found all the wiring f**k-ups yet on the speed sensor. BTW, discovered that if you can't get all this very expensive diagnostic kit to talk in Japanese, the overdrive lamp can be used as a diagnostic aid if you have a short piece of wire to stick into the big socket under the bonnet. It flashes the error code on the overdrive lamp for each ECU as you select them with the piece of wire. Saves on umpty thousands of pounds of plug-in diagnostic tool. Oh yes (cough) I also came away with a 3" thick Toyota JZA80 Repair Manual. I did contribute £25 to the coffee fund, but I thought it seemed a good deal. If I get time, I'm going to look at making a connector to connect the diagnostic port to a laptop. I haven't had time to see if the interface is described in detail yet, so I'll be looking with great interest.

In the thread on traction control, Ash said.... Aha a clue! Switch off the slip control. I'll try that, thinks I; so I did. My usually slightly lumpy gear changes (it's an automatic, before you start) are suddenly smooth as a babies bottom, up and down through the box. It now changes down without so much as a flicker, whereas before, it jerked slightly. Difficult to say going up the box but I'll try it more tomorrow. Does this clue give anyone any ideas?

Have you got the full URL to the actual article Gav?

and while we're doing the double act, didn't you get some quite aggressive pricing on F1s recently?

Oh yes! :biggrin:

IMHO, I think it's between these two. Granted that they sometimes seems to be comparing chalk and cheese but overall it's gotta be one of these.

"It's in the post" although I'm not sure I'm going to be the best judge. I think the best option will be if I get it dyno'd at Powerstation before I fit it, then again afterwards; in fact I might just fit it there and then. I'll see when it arrives and what PS's costs for that are. BTW: apparently HKS recommend cutting the wire to the bulb (spit!). Take the bulb out. (Edited by Paul Booth at 3:45 pm on Aug. 17, 2001)

PIC chip, drool slobber, more more. Wanna know how sad I am? I'm actually thinking of giving up the Beeb to go and be Software Director at a company who do the kind of work that will allow me to make controllers for my car (in my own time); probably using PIC chips.

I thought it was your post Phil but I couldn't quite remember (it's an age thing)