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Thread: 1993 ls400 - 1uzfe

  1. #1

    Default 1993 ls400 - 1uzfe

    Alright so I am trying to lay out all my wires and see what im cutting and what im not and how I am putting this in. From the Manual, I see this:

    Screenshot from 2015-02-17 17:39:54.jpg

    This means nothing to me. a bunch of gibberish i have no idea what the hell it mean lol But then I look at the LS400 diagram, and it says this:

    Screenshot from 2015-02-17 17:41:08.jpg

    Is that really all that has to be wired in for that???

  2. #2


    Sorry, I am confused. You have uploaded a picture from the MAPECU pdf manual and a wiring diagram for a MAPECU2 or MAPECU3. The MAPECU does not have the 18-way connector shown on the 1UZFE wiring diagram. The MAPECU only has a 16-way connector and does not control ignition timing like a MAPECU2 or MAPECU3. Which MAPECU do you have?
    MAP-ECU Support

  3. #3


    I have the MAPECU3 - I bought brand new from a speed shop in California - but do I just follow what you have listed on the LS400 diagram down to the T and it will control the timing and everything? or is there things not shown on that LS400 diagram that are supposed to be done that arent listed on that specific page???

  4. #4


    Alright so I have a KV style MAF - and I want to remove it. The Lexus diagram is here:

    Screenshot from 2015-02-20 21:35:55.jpg

    And your diagram says this:

    Screenshot from 2015-02-20 21:40:16.jpg

    So the markings from Lexus VS the markings on the MAP page, im not sure what distinguishes what

  5. #5


    You follow the LS400 wiring diagram for the MAPECU2/3 from our website and it will control fuel and ignition timing. The generic diagrams you pointed out in the manual are just that, generic. The MAPECU3 Blue wire on the 16-way harness replaces the KS signal from the KV style MAF sensor. The LS400 has dual distributors with an igniter per distributor, which is why you only use 2 ignition timing channels.

    Hope that helps.
    MAP-ECU Support

  6. #6


    I need some information thats a little more concise - I want to do this absolutely correct because I cant afford a mistake on it - The blue wire replaces the KS signal - so I run the blue signal wire to the ECU and then follow the other wires from your diagram, and run those to the ECU - and then I can remove the MAF and put my stainless intake on?

  7. #7


    And this highlighted thing here, where does that connect?

    Screenshot from 2015-02-22 18:52:30.jpg

  8. #8


    Another thing. The wiring diagram shows one wire from the ignitor, and there is two a piece. which wire am I cutting into?

    Screenshot from 2015-02-22 19:36:35.jpgScreenshot from 2015-02-22 19:53:33.jpg

  9. #9


    Sorry, I don't understand. This is the wiring for the MAPECU3 18-way harness.
    MAP-ECU Support

  10. #10


    Our wiring diagram shows the colour code of the OEM ECU harness and the pin number, e.g. IGT1, pin 24, BLK/RED. The X on the diagram indicates a wire cut as per the diagram. The extract from the OEM ECU pinout is very small and hard to read but the pin numbers seems to match our diagram. If you wire this way and load the right base table, you can remove the KV MAF sensor. You will have to install the supplied resistor as per the note on the wiring diagram if you do remove the MAF sensor.

    Is this your first ECU installation? If this is your first experience installing an tuning MAP Conversion then I recommend you keep the MAF sensor and run MAF Intercept mode. MAF to MAP conversion is not a simple plug in affair.
    MAP-ECU Support

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