mr2_ecu_wiring.doc -

By Bruce Sullivan,2014-02-24 02:35
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mr2_ecu_wiring.doc - mrtwo.netmr2_

    There are lots of ways to wire it. The main question that dictates what needs to be done is what harnesses you have or are getting.

    It should be noted that everyones wiring is going to be different. I choose not to wire the car like a Turbo in terms of Idoit lights and warnging. I figure I check my oil often enough. You have to decide on your own whether that is what you want.

When I did my 92NA to 92T swap I had the engine harness. That means I had two

    of the three plugs to the ECU. I also had the third plug cut. I had all of nine wires (literally) to splice. I did not, however, choose to wire the idiot lights or turbo gauge. I also don't have PS or ABS. All this simplifies things greatly. If you look in the EFI troubleshooting section of the BGBs Vol 1 , there are pinout diagrams for the NA and Turbo ECUs. You may need to source both a 91 and 93. This section shows you what every important circuiut is looking for volage and resistance wise. The things I personally found were:

    BATT: 12V+ constant. Run the Batt from the Body - ECU plug on the 5SFE to the corasponding plug on the 3SGTE.

B1: 12V+ Keyed: Run +B from the 5s to the 3s

    +B1: 12V Keyed: Technically the same wire as +B they are spliced frim one source. Again match 5S to 3S.

    FC: Fuel cut. This is the line that the ECU can power and un power the Ciruit opening relay to turn on and off the Fuel pump. Pick it up from FC of the 5SFE body - ECU harness plug (marked FC also) This one actually goes to one of the engine plugs on the 3SGTE ECU so run it from the body plug to the engine plug. (read the diagrams to figure out from where to where)

    STA: Starter. This just needs a low amprage signal from the starter to tell the ECU you are cranking. Pick it up at the Starter relay (green next to ECU). Read the digrams to figure which of the 4 is low amp power.

    ELS: Engine Idle up Diode. This tell the ECU to increase the idle when the headlights or defogger is on. Pick up from the 5SFE body - ECU plug (again marked ELS)

    W: Warning light. Runs Check Engine Light. Pick up W from 5S body to ECU plug.

    AC1: I ran A/C here from the 5SFE plug. I have yet to try my AC because I need to recharge it. The line broke during the swap.

SPD: Speed Sensor. Both cars have it. Run the one to the other.

    That was all that was nessisary to get the car started, and to have every system work the same as when it was an NA. I don't have a Cooling fan light in my dash. I don't have a low oil light. I don't have a boost gauge (stock). I do have low oil pressure, water temp, Tach, Speedo, CEL, Voltmeter. All these work fine.

    It should be noted that from a 92NA-92T the plugs in the Engine compartment fuse box fit and worked fine. Also the Engine to body harness (white plug) in the trunk pluged right in. There were only two or three wires on the 5SFE and probably 18 on

the 3SGTE. Most of these were idiot light hook ups.

    Going from a 91NA to 93T may or may not have these plug and play luxuries. You will have to look at EA1, EB1, and EA2?? to make sure that each wire does the same thing. I did this even for the 92-92. I know the plug in the trunk WON'T work. But the majority of the stuff on it is extrainious.

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