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Discussion Starter · #81 ·
The rear of the circuit board is what I call this side, where is backs onto the metal case:-



I would love to get my hands on one, but it is not essential.

My aim here is to find an ECU that MR2 / MR-S / Spyder owners world wide can easily source and use in their cars. Something that can be bought in most areas easily.

The connector/adaptor PCB I will design will be open source and anyone who feels capable can maybe use this same path.
 

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TBH I would go with a Pontiac Vibe ECU. These are functionally identical to Corolla/Matrix, but they have no immobilizer. Although I am not 100% sure about 2003/2004 models, I believe that the immobilizer architecture is different between Spyder and Corolla/Matrix, and it may be difficult to get around it - not impossible, just another added layer of difficutly to overcome. The difference is in the use of an external immobilzer module, under the dash, that stores the key codes. Toyota adopted this newer strategy to allow replacement of ECU without reprogramming. It applies for sure on all 2005 and later vehicles.
 

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Discussion Starter · #84 ·
TBH I would go with a Pontiac Vibe ECU. These are functionally identical to Corolla/Matrix, but they have no immobilizer. Although I am not 100% sure about 2003/2004 models, I believe that the immobilizer architecture is different between Spyder and Corolla/Matrix, and it may be difficult to get around it - not impossible, just another added layer of difficutly to overcome. The difference is in the use of an external immobilzer module, under the dash, that stores the key codes. Toyota adopted this newer strategy to allow replacement of ECU without reprogramming. It applies for sure on all 2005 and later vehicles.
There is good reason for my selection of this small case ECU, I have spent quite a fair few hours finding/studying wiring diagrams and mostly dead ends. These small case ECU's are fitted to earlier vehicles that appear to have no immobiliser, and some later cars which do have immobiliser. They have the original manual throttle. And I "think" they operate the cluster in a similar manor to the the MR2 but I think the Oil pressure warning light and the temp gauge will not work.

But I am open to suggestion, so when you say Pontiac Vibe ECU, can you tell me a part number?
 

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I have been messing with my MR2 for a few years now, but what holds back my dreams is the factory engine management, or more importantly the option to mess with the original engine management without going standalone. This first world problem has kept me awake at night for quite some time now.

My MR2 has the ECU part number 89661-17730 on the box and inside it contains the cpu 151815-5431 97CW42AF-3448.
Which is a LQFP120 Toshiba TLCS-900 series, with 128k ROM and 6k RAM, and unfortunately it is a Masked ROM so no reflashing is possible.
I have bought a few different standard ecu's from different global markets, but they all have the same chip. Too many hours I've wasted on finding a solution to this problem, it is unfeasible to develop a daughter board for this original ECU, although possible as it has been done by some of the Japanese big name tuning companies.

Anyway, I have found an ECU from a USA spec corolla ZZE130, which very handily comes with the 1zz-fe engine too, but it has a wildly different ECU. The part number I have is a 89666-02140, and the best bit is, it is based on a Hitachi 76F0004 microprocessor, which can be easily re flashed with some widely available tools thought the OBD2 port on the K line. It can even be "updated" with techstream, but other aftermarket tools include PCMflash with "Module 35" which also does checksum correction too, and there are many others that support this ECU.

Now I have mapped out all the pinouts for both the original MR2 ecu, and the ZZE130 ecu, and it all looks pretty compatible, except for some of the dashboard functions like the temp gauge, and the knock sensor.

So my next step is to build a conversion harness from the connector from a spare MR2 ecu, and the plugs from a ZZE130 corolla, and give this idea a shot to see if it will even run on it firstly, then start mapping out the fuel and ignition tables.

I'm putting this post out there to see if anyone else fancies coming along for the journey? Does this sound like something that would float your boat?
View attachment 73173
Good luck look forward to hearing how your efforts go
 

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Regarding the cluster, you would want to verify whether the ECU is using MPX for its serial communication interface, or CANbus. All 2005+ will be CANbus. For the "transitional" ECU's, 2003/2004, I am not sure. If it's MPX, then you have some hope of getting the cluster to work, iprovided that Toyota is following their own standard for the BEAN communication consistently across models. If it's CANbus, then you would need a bridge. It woul surprise me if for 2003/2004 Toyota runs BEAN/MPX with the new chipset that runs CANbus beginning in 2005, but anything is possible. One way to determine the answer to this question is check the factory service manual.
 

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Discussion Starter · #91 ·
From what I can tell, the corolla cluster for this application neither uses CAN or MPX to communicate with the engine ecu.

It uses 4 pins:-

C17 = Speed signal > pin 10
D5 = Rev counter > pin19
C14 = Temperature water > pin8
D11 =Engnine warning light > pin 33
Cluster pin 21 goes directly to the oil pressure sensor switch
cluster pin 31 goes directly to the alternator/generator

While the MR2 sends Temperate / Oil Pressure / Charge signals though the MPX1 + MPX2 data lines
 

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Discussion Starter · #92 ·
There are 2 other interactions that may come with side effects.

The MR2 engine ECU has a connection to the ABS
Engine ECU "ABS" B16->> ABS "TRA" B18
The fact it is called TRA points towards traction control? maybe some kind of power cut signal that the ABS sends to the Engine

The MR2 Power Steering EHPS has 2 connections to the engine ECU
B1 "IDUP" (idle up?) ->> B19
B6 "EFI" ->> B25
(But toyota appear to have forgotten to include this in there EFI wiring diagram :rolleyes:)

So before I get too deep into this, first I must disconnect these 3 wires to make sure both the EPS and ABS work with these removed.
 

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In other ECU swaps, specifically 2zz swap which does not have EHPS pump control, the pump just stays on all the time with key in run position. I believe someone has come up with a solution for this, I may have even written something about how to get around it. But note that this "feature" is nice when pushing a car around in the shop. Ha ha.

The traction control is in option in the US only on SMT vehicles. I believe the system operates by monitoring inputs from VSS (in trans) and yaw sensor (located near the ECU) and controlling the electronic throttle body. Don't really know, never had to deal with it. SMT guys (like @suoiruc) would know more about this. Anyway you are never going to get any ECU to interoperate with the SMT TCM, so don't worry about it, those vehicles are not candidates for your ECU swap.

PS> Don't forget A/C. In Spyder, A/C control utilizes MPX.

PPS. It's interesting that Toyota anticipated a complication arising from transitioning from BEAN to CAN in the cluster for this series of vehicle, so they used neither. Way to slice the baby in half.
 

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Discussion Starter · #94 ·
I don't have AC, and here in the UK it is certainly not mission critical :p

So this is the wiring plan, my eyes are going funny from staring at wiring diagrams all night.....

I'd prefer the power steering pump not to run all the time when the engine is off, as it will nail the battery quickly, so I will solve that problem.

Temp gauge is not so easy to do a crude fix. The charge light and oil pressure light are very easily solved by slicing a couple of traces on the cluster and running wires to the ecu = crude fix.

A really clever person would make a little arduino box that the temperature + charge + oil go into, and it spews out the correct packets for the MPX1/MPX2 data lines. But that person certainly isn't me.

I will find a free night or two, bodge together a really ugly conversion harness connector, and see if I can make the car run.
 

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I don't have AC, and here in the UK it is certainly not mission critical :p
I am in The Netherlands and I prefer to take my MR-2 Spyder over my MX-5 in the summer because it has AC.
For me, AC would be an essential.

A really clever person would make a little arduino box that the temperature + charge + oil go into, and it spews out the correct packets for the MPX1/MPX2 data lines. But that person certainly isn't me.
Mark from Frankenstein motorworks has this available: MR2 Spyder Body Controller / Junction Box — Frankenstein Motorworks
 

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Discussion Starter · #98 ·
His little arduino project really does the biz!


I think I will do my first prototype just to make sure the bare bones start/runs/drives etc.

Then when I draw up the adapter PCB, I will include a spot to solder in the arduino nano, with all the data lines etc connected in. And it will all fit inside the standard MR2 ecu case.
 

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Discussion Starter · #99 ·
I am in The Netherlands and I prefer to take my MR-2 Spyder over my MX-5 in the summer because it has AC.
For me, AC would be an essential.
I do not have an AC model so I cannot personally sniff the packet data etc to get it working.
BUT I've looked at the wiring diagrams, and I think it would be very straight forwards for me to include the A/C control electronics into the adopter PCB. It would just take someone to sniff their cars A/C BEAN packet data, then write a little Arduino code to implement it.
 
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