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Discussion Starter · #1 ·
Hi.
I'm Daniel, I'm working on an IS300 related project and just wondered... will anybody care?
What I'm making is a device that will hook up a standalone ECU (Ecumaster Black in my case) with all the convenient bells and whistles that AFAIK would require a parallel harness and running both aftermarket and stock ECU at the same time. My goal is to ditch the factory ECU completely.
The things that i have in mind are
  • AC
  • Engine temperature gauge
  • Cruise, snow, oil etc. indicator lights
  • SNOW button
  • Cruise Control
  • Outside temperature gauge
I have a prototype ready and accomplished pretty much everything from the list above, minus the Cruise Control. Haven't tested that yet although i have the DBW working which everyone said was impossible (?) and said to do a DBW-Delete. Other stuff is pretty much functional and tested with EMU but I'm still making a harness to put EMU permanently in the car.
This device is my engineering degree project but i figured that maybe it may do some good for other IS folks. In theory it would also work for other cars with MPX like LS400 or Supras.
So tell me, how many of you are running a parallel harness and would be interested in getting a converter like this? I could make a few more than I need. Don't know the final price but I guesstimate it would be in the ballpark of 200-300 USD.
As a side question, why exactly the DBW is considered impossible/not recommended? I have it hooked up and moving. Autocalibrated in EMU software and did a movement test but EMU is not fully connected so the car doesn't run on it.

Cheers
 

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Welcome to the forum and the engineering trade, Daniel. Sounds like a neat project.

You'll find there are a lot of folks with parallel/piggyback ecu arrangements, so I would think there'd be some interest.

Isn't the Toyota MPX/BEAN architecture just a proprietary CANbus? Where I'm going with that is most ecus on the market these days are capable of working on a CANbus - the only question is the protocol of the bus. It seems you've figured out that protocol and identified the individual functions (which is really cool, I'd like to know more about how you did that), so can't that just be programmed into the bus of any ecu that has CANbus support?

For example, the Link G4+ and G4x are not only capable of this, but enterprising folks have figured out the MPX protocol the same way you have. I'm a gears/springs/levers type engineer though, so perhaps I don't know WTF I'm talking about. Maybe the MPX/BEAN system requires special hardware...?

Another thought: I think there would be a LOT of interest in a similar device that were able to control the automatic transmission in these cars. The AT guys are married to the stock DBW throttle body arrangement and ecu in order to have a working trans.
 

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Discussion Starter · #3 ·
MPX is nowhere near CAN. Proprietary bus created by Toyota, basically one wire needed for communication but ECUs are arranged in Ring network hence why there are 2 MPX wires for each ECU. My device translates some of the MPX signals to CAN signals and vice versa.
As on how I figured out the network... partly it was already documented on the internet, partly i was just driving around with a homemade MPX sniffer and just looking at signals and correlating that with what I'm doing with the car. I'll post the full explaination of frames and signals here or on my github.
About the auto transmission. I might try doing that in the future. As of now i don't even have a suitable car. My is300 is a manual.
 

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As a side question, why exactly the DBW is considered impossible/not recommended? I have it hooked up and moving. Autocalibrated in EMU software and did a movement test but EMU is not fully connected so the car doesn't run on it.
Its not considered impossible, as mentioned above most decent ECU manufacturers now have DBW features built in, and can adjust the response to be instantaneous. The main problem is with the OEM ECU setup as most dont like the level of interference the DBW gives, particularly in delayed throttle response. e.g. Often when i coast up to a roundabout up the road from my home, see a gap and hit the gas the car delays the throttle enough for me to think it isnt going to work and hit the gas more, which it then comes on hard and launches me across to almost into another car. I believe if it didnt have that delay most would be pretty happy with running it, it also is needed for traction control, cruise control if you have that option, and a few other functions. Some want to go to larger throttle bodies which means ditching the DBW unless you can get one from another similar DBW system.
 

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Sounds pretty neat. I may not be understanding everything though. I’m running AEM Infinity and the stock ecu together, on a MT car. The AEM is controlling DBW on a 2jzgte vvti throttle body. Everything the car came with factory works except cruise (ect and snow button don’t work either because the stock ecu is totally divorced from the DBW motor), and because AEM is a “race ecu” and therefore don’t see a need for cruise in a Motorsports ecu. I don’t see how any kind of adapter could add cruise control, if the aftermarket standalone doesn’t support it, unless you’re sharing control between stock and aftermarket ecus.
 
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