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Thread: Can I tune open and CLOSED loop? on a 1UZFE?

  1. #1

    Default Can I tune open and CLOSED loop? on a 1UZFE?

    What up guys,

    Looking for some info on tuning open and closed loop with a MAP-ECU3 (latest MAP-CAL installed)
    I have a MAP-ECU3 installed in a supercharged Lexus GS400 (1UZFE-VVTi) Everything is working fine. Wiring is good, I have a PLX wideband interfaced with it which is working well with the MAPECU. No issues with installation.
    I have read that with past MAPECU's you can load two maps; one to control open loop and one to control closed loop. And that you can switch between loops via a toggle button.
    I also have read that with MAPECU3 this type of mod is not needed because you can have the MAPECU3 switch maps via coolant temperature. How would I achive this?
    I have to check the wiring manual again but is coolant temp allready monitored by the MAPECU3? or is that an upgrade that I need to purchase?
    My car has enrichment on start up so it running rich in closed loop because of the larger injectors that I have installed. can I tune in closed loop with the MAPECU3? Do I have to remove the O2 sensors and use simulatiors to do this?
    Lastly, using the coolant temp how would I switch maps? I assume that option is in MAP-CAL somewhere.

    Thanks!!

  2. #2

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    Some of that is not quite correct. You don’t need to toggle maps for open and closed loop tuning. The O2 Adjust function is designed for the stock O2 sensors but we haven’t tried it on the 1UZ. It works best on a vehicle with OEM wideband sensors and you use the MAPECU AFR Calibrator. What year is your GS400?

    Btw, you cannot use the coolant temp to swap maps.
    MAP-ECU Support

  3. #3

    Default

    Quote Originally Posted by MAP-ECU Man View Post
    Some of that is not quite correct. You donít need to toggle maps for open and closed loop tuning. The O2 Adjust function is designed for the stock O2 sensors but we havenít tried it on the 1UZ. It works best on a vehicle with OEM wideband sensors and you use the MAPECU AFR Calibrator. What year is your GS400?

    Btw, you cannot use the coolant temp to swap maps.
    Ok. that narrows it down..lol
    The Car is a year 2000 GS400.
    I have installed a Wideband and it is connected to the MAPECU3.

  4. #4

    Default

    I believe the 2000 model year is the 1998-2000 version which uses the normal narrowband sensors, 4 of them I believe. The idea would be to run the pre-cat sensors through the O2 Adjust function but we haven't done it on this particular vehicle before.
    MAP-ECU Support

  5. #5

    Default

    You dont need a second map in MAPCAL, but you do need an OBD reader which can give you info of LT/ST fuel trims to tune closed loop.

  6. #6

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    Quote Originally Posted by Daou View Post
    You dont need a second map in MAPCAL, but you do need an OBD reader which can give you info of LT/ST fuel trims to tune closed loop.
    Ok thank you.
    Still trying to figure this thing out.

  7. #7

    Default

    Quote Originally Posted by MAP-ECU Man View Post
    Some of that is not quite correct. You don’t need to toggle maps for open and closed loop tuning. The O2 Adjust function is designed for the stock O2 sensors but we haven’t tried it on the 1UZ. It works best on a vehicle with OEM wideband sensors and you use the MAPECU AFR Calibrator. What year is your GS400?

    Btw, you cannot use the coolant temp to swap maps.
    I cutted OEM o2 sensor signal wire(and emulated heater with resistor to remove MIL) on my 2jz. is that correct?

  8. #8

    Default

    If the OEM ECU is OBD2 it will probably throw a CEL if you cut the sensor wires. Have you tried your plan already to see what happens?
    MAP-ECU Support

  9. #9

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    I'm not cutting any O2 sensor wires, I dont need an unessessary CEL poping up..lol
    I need my Fuel trims as close to zero in closed loop. Trying not to trip any CELs. I live in NY with strict inspection laws..lol

    MAPECU man I do have a OBD reader and it is helping me ajust my fuel trims. Thanks.
    I have posted some other quesitons.
    Thank you for your help though!

  10. #10

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    The post about not cutting the sensor wires was in response to beast_drc as he said he was going to cut the wires. Hope that clarifies the answer.

    You're welcome, hope it helps. Sorry we have been slow responding to some questions.
    MAP-ECU Support

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