Kruso

First things first, to keep a dead horse from being beaten further...

I have verified that the Aristo ECU and the MKIV JDM Supra ECUs are different as it relates to map sensor voltage reading. Supra, both USDM and JDM, uses the 4.3v clamp via the bcc to bypass fuel cut vs the Aristo uses some form of pulse signal or equivalent.

I have tried on three separate JDM Aristo ECUs a new SW20 BCC and immediately after installation, car drives like complete crap. Same car drives perfect on JDM Supra MKIV ECU. Another one of the Supra guys have verified the same findings...

Having said all of above, who has verifiably overcome fuel cut on an ARISTO ECU and how?

The information is not up for debate contrary to what almost every single thread suggests both on SF and CL. I am aware of the lowering of the voltage ie 4.2-4.1v. I'm sure this is going to ring a bell with several of you guys... Anyone?

soarer13oy

iTrader: (13)

The Aristo ecu is more similar to the jdm Supra than it is to the usdm supra. Both aristo and jdm supra ecu uses only the map sensor. The usdm supra uses the maf as well as the map. A friend of mines has a jdm supra swap, but can run the car with an aristo ecu. He actually has a mines aristo ecu installed as of right now. I have an aristo swap and i do not get boost cut after installing my bcc.

stockhatch

iTrader: (12)

SW20 BCC worked fine for my Aristo swapped car as well. Maybe you have a bad BCC?

Kruso

I'm not sure how that's possible as the same BCC was used on the JDM Supra ECU and worked fine. Anyone know of a possible difference between the different years of Aristo OBD I ECUs?

Ali SC3

iTrader: (10)

list your part number maybe the ecu is not odb1 or something else is wrong on the BCC.
It shouldn't change how it runs at all with the BCC installed properly, really sounds like a wiring issue.
The mr2 bcc controller should work perfectly on all gte ecu's, they all use the same basic map sensor and all the ecu's trigger boost cut from map sensor voltage and a few other inputs like tps but those generally don't change with just swapping ecu's.

also at higher elevations your boost cut goes up because the map sensor reads absolute pressure, so in denver with my engine off my map sensor is reading about -2psi (negative) so to reach the same 4.3 V I actually hit 17 psi on my boost gauge (which reads 0 when the engine is off, most gauges do not read absolute pressure just relative pressure) and that's where the fuel cut happens for me. Sort of like a built in elevation calculation so no matter what elevation you are at you will be making similar power just the psi will change. Toyota knew what they were doing when they programmed these ecu's probably for some JDM mountain cruises.