1JZ patch harness to 2JZ Aristo problem

[eyesoarer6]

I posted this up in the other forums but wanted to get your opinoins.

I purchased a jumper harness for my 1.5JZ swap to run a Aristo 2JZ ECU in my SC300 but the car is running like crap and I have a few questions. First off its throwing three DTC's- 21,31 and 47 which are the O2, Map and sub TPS circuits. The fuel pump stays ON with the key in ACC, engine OFF. I checked all the fuel pump relay pins coming from the 1JZ plugs to the 2JZ jumper and everything looks to be in order(2pins). Would the 12V mod cause the pump to run all the time with the 2jz ecu?

Other question is about the MAP circuit. How would I check this circuit? Does the 1JZ run the voltage as the 2JZ? Some of the guys on CL said it may be using different pinouts or voltage but I checked the pinouts and that doesnt seem to be the problem so Im thinking voltage.

The O2 issue, someone told me that the 1JZ uses the 2 wire sensor while the Aristo uses the 4 wire heated sensor and suggested I run the 4 wire sensor.

What do you all think?

 

[kneedragger85]

Wow, they gave you a lot of wrong information at CL.

You need to seperate the wiring for your fuel injectors. The 1JZ runs batch firing to two injectors at a time while the Aristo runs sequential.

Your fuel pump stays on because the Aristo/MKIV use an external fuel computer (just a glorified relay) while the 1JZ ECU controlled the fuel pump.

The 1JZ and JDM 2JZ's run the same MAP sensor.

The O2 sensor on both the 1JZ and JDM 2JZ are 3-wire heated sensors. You can get one by going to an autozone and telling them you have a 1993-1995 Supra TT and need the 3-wire upstream O2 sensor.

 

[eyesoarer6]

Wow, they gave you a lot of wrong information at CL.

You need to seperate the wiring for your fuel injectors. The 1JZ runs batch firing to two injectors at a time while the Aristo runs sequential.

Your fuel pump stays on because the Aristo/MKIV use an external fuel computer (just a glorified relay) while the 1JZ ECU controlled the fuel pump.

The 1JZ and JDM 2JZ's run the same MAP sensor.

The O2 sensor on both the 1JZ and JDM 2JZ are 3-wire heated sensors. You can get one by going to an autozone and telling them you have a 1993-1995 Supra TT and need the 3-wire upstream O2 sensor.

I forgot to mention that I wired it up for sequential. I seperated and ran the injectors signal wires individually.

As for the fuel pump. Yes the SC300 has its own fuel pump ecu. When I ran the 1JZ ECU I had no issues, ever since I added on the jumper harness and running the Aristo ECU the pump is ON constantly with the key in. Must be some kind of wire mishap on this patch harness.