Fully re programmable Toyota OEM ECU for the MR2 1ZZ to allow remapping etc

Started by threepot, May 15, 2022, 11:09

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threepot

So maybe not our exact MR2 ecu.  ;)

But I am building a magic PCB to make a Corolla 1zz-fe ecu fit into our MR2 case, 100% plug and play.
I've been posting on spyderchat here https://www.spyderchat.com/threads/possibly-a-factory-re-programmable-toyota-1zz-fe-ecu.154212/

The corolla ECU is from a 2004 1zz-fe, and they are fully re programmable via the OBD2 port.

So far I've managed to bodge together an adapter just to see what works and what doesn't.



And I've started the car and driven it round for half an hour. Here is the first start....


The goal is to design a circuit board that anyone with basic soldering skills can assemble, which will allow for a 100% plug and play fitment into the MR2. Giving MR2's the re-flashable engine management system they really deserve.

This will open the door to being able to remap the ECU, and with the right people they could even modify it to allow forced induction tuning.

If anyone out there as a wizz with Arduino/C++ then some help writing good code for the cluster comms adaptor would be helpful.





J88TEO

Good work - though I know nothing about remapping the ECUs.

threepot

Part of this ECU conversion means interfacing with the old "BEAN/MPX" instrument cluster.

I've bought a spare cluster and made a harness etc so I can run it on my desk at home to experiment.

Some things are not what they seem! The temperature gauge on an MR2 lies a hell of a lot.

Here is a video where I am incrementing the value sent by the engine ECU in exactly equal 3 steps, but the gauge response is completely wonky. Basically it is linear upto about 80 degrees where it hits the mid way point. Then it stays still at the midpoint to about 110 degrees, then just over it shoots up like a rocket.


fawtytoo

Quote from: threepot on May 20, 2022, 09:45Some things are not what they seem! The temperature gauge on an MR2 lies a hell of a lot.

Here is a video where I am incrementing the value sent by the engine ECU in exactly equal 3 steps, but the gauge response is completely wonky. Basically it is linear upto about 80 degrees where it hits the mid way point. Then it stays still at the midpoint to about 110 degrees, then just over it shoots up like a rocket.
I think that's by design. It's not supposed to be linear nor give a temperature reading.

The most important part of the range is between normal and hot, so the needle needs to move faster there so you get a more "instant/noticeable" notification of temperature increase.

EDIT: Read "instant" as "noticeable".
"My name is not important" - Slartibartfast

Alex Knight

Spot on above.

When the gauge is reading 'normal', that means that the coolant temp is within a given range, with a +/- tolerance.

If it is below that range, it will display colder than normal.

If it is above that range, it will display hotter than normal.


It's common practice on almost all cars, so the average Joe doesn't see all the little temperature fluctuations.

fawtytoo

Also, I think the temperature sensor does not measure temperature anyway. It's just a "reading".
"My name is not important" - Slartibartfast

Petrus

Quote from: fawtytoo on May 20, 2022, 11:59Also, I think the temperature sensor does not measure temperature anyway. It's just a "reading".

Yes, that was observed by others too.
It is a bit of a ´user friendly´ light disguised as a meter and as such precluding customer worries.
I suspect many cars are so fitted out.
The family car has it too. When the thermostat want dodgy, the meter was midway, then hit the roof with the warning led lit up. Next the led went out and the needle settled below mid again. Repeat.

threepot

The temp gauge is a thermistor with reasonable accuracy and resolution. I have plotted and calibrated that too. It measures the coolant exiting the cylinder head pretty precisely.

On a yaris cluster there are 2 LED's = blue for cold and flashing red for over heating. But then buyers feel the manufacturer is cheating them out of a "proper temp gauge" - even though cars have no such thing anyway.

The video is a good practical demonstration to make people aware that just because their gauge always points to the middle, it doesn't actually mean their coolant system is actually working correctly.

Petrus

The latter is the down side yes. But hey, they are now making cars for people who should not be driving. Driver aids are the mandatory norm so the logic of a slightly misleading temp gauge a moot point no?!
Yes, Í and several more here on the forum would like a meter to indicate real data but then I would like a spud gun turret on the cross bar behind the seat  ;D  Just kidding: I want a carbon bonnet, plastic windscreen, loud pipe, supercharger and a simple flashable ECU  8)

J88TEO

Quote from: Petrus on May 20, 2022, 12:30I would like a spud gun turret on the cross bar behind the seat
I want that too....maybe after the conflict in Ukraine has ended...plenty of USA arms on the black market then!

thetyrant

Good project hope you manage to get it sorted :D

Regards temps gauge/sensor i observed the same when i had my Link G4 setup in the roadster, its pretty normal on cars these days and many dont even have a gauge just a overheat light once it gets silly!  also modern cars run just same when cold as warmed up hence a lot get thrashed from cold as no gauge and no fiddling with the choke until its warmed up like the good old days :)
Ex-2005 roadster  owner, i will be back :D

threepot

Well the PCB's have been made and waiting on a Fedex collection. What are the chances of this actually working?!




thetyrant

Out of interest have you found a way to interpret hex code and change the mapping as yet ?

 Many years ago when tuning my Mitsi Evo2 using an Ostrich emulator plugged into the socketed rom on board we were able to remap it, however it took quite a while until someone with much larger brain than mine could pull apart the Hex and work out which parts did which in the tuning and make it work in software interface we could understand to change things.

Keep up the good work :D
Ex-2005 roadster  owner, i will be back :D

threepot

Yes, correct, there is someone who is quite familiar with this generation of Toyota ECU and have said all the fuel, ignition, VVT tables etc are quite obvious. I think they will help me create a WinOLS definition file for this platform.

threepot

So tonight I've put the 2 wire knock sensor onto my 1zz-fe MR2.
And I've acquired another one of these Corolla ECU's but his one is a manual gearbox one this time (duhh!).

Taken it out for a gentle drive, and then a full on spit roasting. And I get.....




No engine warning lights, and no fault codes triggered.

It's a go'er, this conversion totally works.

Just need to get the adaptor circuit boards done with the Charge/Temp/Oil light converter sorted.

If anyone fancies playing/looking at the flash file, you'll find it here on the spyderchat forum
https://www.spyderchat.com/attachments/896630201500-bin-pdf.89709/

This is the stock flash file, ready to tinker with. And it can be uploaded/flahed in about a minute and a half via the OBD2 port (but you do have to add 1 wire in because the MR2 OBD2 port is missing the "L" line on pin 15 of the socket).

So it end up plugging straight into the MR2's ecu connectors, but 2 wires need to be added, 1 for the knock, and 1 for the obd2 socket.

threepot

PCB's arrived.
I have made some dimensional errors, but for a rev v0.1 they are pretty reasonable.
And it starts and drives the car, which again isn't bad.
Just need to solder in all the Arduino bits now to see if the cluster/gauge stuff works...









Hammond

05' silver

TheTigerUK

Quote from: threepot on May 24, 2022, 16:48PCB's arrived.
I have made some dimensional errors, but for a rev v0.1 they are pretty reasonable.
And it starts and drives the car, which again isn't bad.
Just need to solder in all the Arduino bits now to see if the cluster/gauge stuff works...










You guys are clever, I thought I had done well changing my cluster bulbs !! :)
Say it with love, say it with flowers but never, never, say it in writing.

Not perfect and not cheap :)

Petrus

I find this a fáscinating thread with almost the parallel of the evolutionary development of an island species.
Knowing enough to get me into trouble but not understanding sufficiently to rescue myself, I have learned to bow to experts. I think I still have a LandRover TD5 ECU I bodged soldering chips in multilayers lying about sómewhere as a tangible lesson.

Following this both here and on Spyderchat. My car is an n.a. smt  but that is irrelevant for my appreciation.

threepot

There is some software called BitEdit, and you need a USB security dongle to run it and add modules.

"Bitedits Module Toyota Denso Petrol 1" just so happens to have the full maps/tables definitions for these 1zz-fe ecus. All the work has been done.

Bitedit is developed and manufactured in Russia! Buying a USB security dongle for it is proving very difficult indeed. If anyone has it then please get in touch.

MrT

@threepot will you be able to offer converted ECUs to this end and possibly facilitate tuning given the rarity of that dongle? I'm not inclined to test my soldering skills on an ECU as I'm less than practiced and have a heavy unsteady hand.

Alternatively I assume with a base map on the ECU any equipped tuner could map the car for their usual price, so if you could supply a converted ECU with stock Corolla map buyers could potentially drive their cars to a tuner (unless trying forced induction).

I'd suggest either on an exchange basis or buyers supply their ECU for conversion? Or perhaps a collaboration with Dick Sloan or J-Spec or other mr2 breakers to source ECUs from cars departed from our roads and recycling. I'd personally be keen to hang on to my original ECU for example but could source a unit to modify myself if need be.

I look forward to hearing of your progress.
Cheers
Tyler

RIPieces: Sable \'05 Roadster \'Red\' edition.
Project: MR-S import (JDM) now my toy and mule for:
SC build OR a 2AR-FXE swap (ref: Frankenstein Motorworks) OR Electric conversion
AND rebody with a fibreglass replica of Porsche 550 Spyder.

threepot

At present I have been somewhat distracted by a certain other MR2, but work on this swap board will continue.

The plan is to make a freely distributed definition file so any half competent tuner can do their best/worst thing with it. The software I will create the definition for (called an XDL) is TunerPro which is fully free to use. But I've had the brakes put on as I am cannot buy  a little USB dongle from the Russian company that has already done the full definitions of maps/tables due to the questionable politics of state warfare etc.

I'd be happy to assemble the odd one or two here and there if the person supplies their own MR2 ECU and Corolla ECU, but part of the fun of this would be putting it together yourself aka 1970's crystal radio kit or some junk from Sinclair Radionics etc.

Rev 2 of the PCB was designed a week ago, but I need to test some of the stuff on the first board to make sure the Rev 2 is going to be fully functional. It has better provisions for the 2 wire knock sensor so no modification to the original MR2 stuff required. I really want it to be plug and play, and fully reversible without modification to the original vehicles wiring harness.



Too many projects yet too many commitments! My little Ltd company saps alot of my time away, then the 2 kids family life drain the rest.


MrT

Ok thanks threepot. I'm not in a rush and am happy to wait for you since it is a huge benefit you will be providing the owners not the other way round. I appreciate your efforts!
Cheers
Tyler

RIPieces: Sable \'05 Roadster \'Red\' edition.
Project: MR-S import (JDM) now my toy and mule for:
SC build OR a 2AR-FXE swap (ref: Frankenstein Motorworks) OR Electric conversion
AND rebody with a fibreglass replica of Porsche 550 Spyder.

MrT

Oh I meant to ask, the MR2 doesn't have a knock sensor does it?.I've just swapped my engine and am sure I didn't connect anything resembling one on the block, unless I totally missed it thanks to a remote plug location. Is it behind/under the intake manifold?

Or is this a retrofit thanks to the Corolla ECU and an opportunity for finer tuning?
Cheers
Tyler

RIPieces: Sable \'05 Roadster \'Red\' edition.
Project: MR-S import (JDM) now my toy and mule for:
SC build OR a 2AR-FXE swap (ref: Frankenstein Motorworks) OR Electric conversion
AND rebody with a fibreglass replica of Porsche 550 Spyder.

Petrus