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    Megasquirt PNP Gen 2

    Hi all!
    I am a novice to standalone engine management, and to (hopefully) make things easier with the MSPNP Gen 2 box offered by Condor Speed Shop.
    I have a few questions regarding this, and please keep in mind I know almost nothing lol.

    Anyway, here's my setup:
    Stock long block M20B25 including a stock ignition and fuel delivery system (distributor on cam, tachometer input from factory ignition coil)
    AFM delete, utilizing Alpha-N
    Throttle position sensor from an E36 instead of stock throttle position switch.
    RHD ITB intake with open trumpets/no plenum.

    So I bought and am currently waiting on the Plug n play box from Condor. It's attractive to me because they advertise it plugs into the factory plug on the factory harness and it even mounts in the factory spot. It even sports a base tune to get you moving. So all I have to do is unplug the factory ECU and plug this new ECU in. No DIY wiring for me to screw up and troubleshoot. Takes the guesswork out of it.

    My questions are:

    1) Is my understanding of this ECU as outlined above accurate? Or is it not that easy?
    2) Will I have complete functionality of the cluster/onboard computer out of the box? Or will I have to modify the setup for speedo/tach/coolant temp/fuel economy/etc to work?
    3) I want a wideband o2 sensor for tuning purposes. Can one be installed in the factory bung in place of narrowband? I don't need or particularly want a gauge, but something that could hopefully be hooked into the factory plug (and not be spliced) so the MSPNP 2 box could read it directly. I would also like recommendations on what the best way to do this is.
    4) Webpage for the MSPNP 2 ecu says it needs a GM open element air intake sensor. Is this necessary for the car to run if I run Alpha-N? If so, why? Taking suggestions for the best way to wire it in?

    Obviously I want to wire as little as possible, preferably none. Wiring is one of my weak spots, and I'd rather focus on the rest of the build instead of troubleshooting wiring. Wiring management is also a pain in the ass, and I want to minimize the effort needed on that as much as possible. Lastly, I want to be able to revert this car back to 100% stock if I chose to, and I don't want to have a molested harness should this happen.

    Thanks in advance for any and all constructive advice, and please understand I am such a novice with standalone lol.
    1969 Chevrolet El Camino - SOLD
    1979 BMW 320i - Traded
    1980 BMW 633CSi - SOLD
    1986 Chevrolet K30 Silverado - SOLD
    1987 BMW 325es - Totaled
    1987 BMW 325ic - Traded
    1990 BMW 325is - First car/Sunday Cruiser
    2004 BMW 325xi - Totaled
    2007 BMW 335i vert - Traded
    2018 Chevrolet Cruze - Totaled
    2019 Subaru Impreza
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    1980 Suzuki GS850 - SOLD
    2004 Harley Davidson Softail - Traded
    2007 Suzuki GZ250 - SOLD
    https://www.flickr.com/photos/155574105@N08/albums

    #2
    The reality is, you are going into custom territory weather you like it or not. Its time to learn what everything inside the ECU does. read the tuning and setup manual over and over again. How every sensor works, how to calibrate every sensor, where to find calibrations. what the calibrations mean. WHY you need every sensor. The ECU is now your number 1 diagnostic tool. Car not running right = get inside the ecu and start looking at why. Data log. looking at sensor readings all the time to learn what is "normal".


    1) Is my understanding of this ECU as outlined above accurate? Or is it not that easy?
    Pretty much youve got it.

    2) Will I have complete functionality of the cluster/onboard computer out of the box? Or will I have to modify the setup for speedo/tach/coolant temp/fuel economy/etc to work?

    It should "plug and play". It is important for you to know how each of these items are setup so in the event that you need to change anything you will know why. and in the event that a sensor is reading weird, you will know how to fix it. your economy gauge wont work any more. no idea about the on-board computer. p

    3) I want a wideband o2 sensor for tuning purposes. Can one be installed in the factory bung in place of narrowband? I don't need or particularly want a gauge, but something that could hopefully be hooked into the factory plug (and not be spliced) so the MSPNP 2 box could read it directly. I would also like recommendations on what the best way to do this is.

    The actual sensor can be put where the old one was. Wide band requires a separate controller as it has a heater in it. So it wont just plug straight into the OEM plug. The controller needs its own power supply. and the signal wires can go into the plug. Someone can probably how they did it. I personally made my own loom (not a b25)

    4) Webpage for the MSPNP 2 ecu says it needs a GM open element air intake sensor. Is this necessary for the car to run if I run Alpha-N? If so, why? Taking suggestions for the best way to wire it in?

    ALWAYS give the ECU all the sensors and make sure they all work properly. So yes your car needs an air intake sensor. It doesn't need to be a GM one, it can be any sensor you like as long as you calibrate it properly. the m20b25 oem air flow meter has an air temp sensor in it. so its a matter of either cutting the plug off the air flow meter and wiring it in, or getting the "male" version of that plug and making a bit of an adaptor.

    Don't get caught up in saying "alpha-N" all the time. Literally all it is is TPS vs RPM tuning. and to be honest its a rather archaic way of tuning. its the "last resort" way of tuning. If i ever did individual throttles i would try my best to create a manifold of vacuum lines from each cylinder to get the best map signal possible. But ive not actually tried that.

    Comment


      #3
      Thank you for response!

      After doing a bit of research I've decided to shy away from a wideband sensor unless I move onto an ECU that has a wideband controller built in.

      And the air intake sensor wiring seems to be the least of the custom wiring. If I use the GM open element, can it be wired into the factory AFM plug somehow?

      It may be archaic, but it's what the manufacturer recommends for the ITB set up. I've chosen to run without a plenum, at least for now, so there's no place for a MAP sensor.
      1969 Chevrolet El Camino - SOLD
      1979 BMW 320i - Traded
      1980 BMW 633CSi - SOLD
      1986 Chevrolet K30 Silverado - SOLD
      1987 BMW 325es - Totaled
      1987 BMW 325ic - Traded
      1990 BMW 325is - First car/Sunday Cruiser
      2004 BMW 325xi - Totaled
      2007 BMW 335i vert - Traded
      2018 Chevrolet Cruze - Totaled
      2019 Subaru Impreza
      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      1980 Suzuki GS850 - SOLD
      2004 Harley Davidson Softail - Traded
      2007 Suzuki GZ250 - SOLD
      https://www.flickr.com/photos/155574105@N08/albums

      Comment


        #4
        how you gonna tune without a wideband?

        Ive been doing some reading too and with ITBS i would be looking at a blended apha-n with speed denesity (map). you can still put a map sensor on ITBs without a plennum. you just need to put a vacumm line between each throttle and the head and then group them together for the map sensor. But again all theory from me. ive only played with megasquirt on non-itb engines.

        Comment


          #5
          IIRC when I was researching the RHD ITB's, he sells a vacuum manifold that you can use to get a MAP reading from the individual TB's.

          You're going to need a wideband. They can be spliced into the stock 4 pin connector so you don't have to modify your wiring harness. I am using the 14point7 Spartan2 wideband wired up that way.

          For the MAP and IAT sensors, you can wire a custom adapter [igtail to use the stock AFM plug to connect both of those sensors. You also might have to rewire the TPS since the E36 has 2 of the pins reversed. I don't have any info on actually doing this since I bought a Dederic MS kit that had adapters included. **This will all depend on how your adapter to main board is configured** You will need to familiarize yourself with which wires from the 55 pin connector goes to what MS input.

          GM 3 bar MAP and open element IAT sensors are easy to use because they have pre-configured calibrations in the firmware. I'd recommend the Delphi 3 bar MAP sensor. I broke several of the DIYAutoTune "American Made" sensors. They are made like junk.

          RISING EDGE

          Let's drive fast and have fun.

          Comment


            #6
            I ordered the GM IAT sensor (perks of working at a dealer with a GM parts dept.) and my tuner has the wideband situation handled for me. I'm gonna try and go without a MAP at first but if I'm having problems, I'll add it in.
            1969 Chevrolet El Camino - SOLD
            1979 BMW 320i - Traded
            1980 BMW 633CSi - SOLD
            1986 Chevrolet K30 Silverado - SOLD
            1987 BMW 325es - Totaled
            1987 BMW 325ic - Traded
            1990 BMW 325is - First car/Sunday Cruiser
            2004 BMW 325xi - Totaled
            2007 BMW 335i vert - Traded
            2018 Chevrolet Cruze - Totaled
            2019 Subaru Impreza
            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
            1980 Suzuki GS850 - SOLD
            2004 Harley Davidson Softail - Traded
            2007 Suzuki GZ250 - SOLD
            https://www.flickr.com/photos/155574105@N08/albums

            Comment


              #7
              Do what you will. I personally would sort out the vac lines for map sensor and even if you don't use it initially the work is done and you dont have to dive under the throttles again.

              Everything i can find put alpha-n is it works ok but is terrible on load changes with constant throttle, ie going up hills which is why most seem to swap to a blend of map and alpha n so you get the map signal and the tps working together to get the both worlds of tuning.

              Comment


                #8
                bridge the 02 sensor relay, and just put an aem inline wideband on the factory narrowband connector, i dont remember if i have the wiring diagram but someone has it im sure. thats what i did on my car, have been running it that way since the beginning of my ms2 experience

                Comment


                  #9
                  Originally posted by 2002tiiguy View Post
                  bridge the 02 sensor relay, and just put an aem inline wideband on the factory narrowband connector, i dont remember if i have the wiring diagram but someone has it im sure. thats what i did on my car, have been running it that way since the beginning of my ms2 experience
                  Stupid question and im kinda bumping an older thread, but ive been having issues with my spartan wide band cutting out right after start up. Would this be caused by me not jumping the original O2 narrowband relay?
                  85% of the time i have no idea what I'm doing

                  Comment


                    #10
                    Originally posted by Slybeanx View Post
                    Stupid question and im kinda bumping an older thread, but ive been having issues with my spartan wide band cutting out right after start up. Would this be caused by me not jumping the original O2 narrowband relay?
                    That is likely the problem, although I haven't seen your wiring. This is the link to the 1989 325i-325is Electrical Troubleshooting Manual from wedophones. Section 1360 depicts all of the wiring to/from the ECU. Sheet 1360-8 show that the oxygen sensor heater relay is powered off of ECU pin 23. This is only powered for startup since the hot exhaust gasses will keep the oxygen sensor warm during normal driving. Looking at Sheet 1360-7, if you pulled power for your wideband controller off of the C140 connector Pin 4 (from the oxygen sensor heater relay), that's probably why your controller is loosing power.
                    sigpic
                    1987 - 325i Convertible Delphin Auto [SOLD], 325i Convertible Delphin Manual [SOLD]
                    1989 - 325i Convertible Bronzit m30b35 swapped [SCRAPPED], 325i Sedan Alpine Auto[DD]
                    1991 - 325i Coupe Laguna Manual [Project], 535i Sedan Alpine [SCRAPPED]

                    Comment

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