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    Another MS2 no spark

    Hi all!

    My turbo iX is so close to running! But I'm baffled. The MS refuses to produce spark. It's an ms2 based unit that was built by someone else and then set up by SSSquid for my specific car- he just replaced the failing ignition driver and some other things and we were fairly certain that would solve the no spark issue. He's been extraordinarily helpful and has spent probably way too much time working on this ECU for me. I imagine he's starting to be as stumped as I am.

    The car is running completely stock ignition and will get spark if I plug in the stock ECU. Tooth log looks good so it seems like CPS signal is making it to the ECU. Car ran great as a DD prior to disassembly.

    One interesting thing is the car would run on a stock NA basemap (poorly, I never worked on the tune) a few weeks ago before any of the turbo stuff was on it. So I don't know what's changed in the meantime. It will not produce spark on that NA basemap now.

    The only changes from stock are-

    42lb injectors
    No ICV
    No AFM
    GM IAT sensor
    Lc-2

    Is there a chance that the coil/cap/rotor are just far enough out of spec that the MS can't drive the ignition system but the stock 153 ecu still can? I don't like the "throw parts at it" method of troubleshooting things like this. Is there anything within the tune that would prevent spark? I may try the test mode to see if I can force the coil to fire- but I'm a little wary of cooking something doing this.

    I'm close to reinstalling stock injectors, ICV, AFM, ECU just for my own sanity to isolate this as an ECU issue and not something on the car side. But I'd sure rather not... I'm hoping this is something stupid and I'm not afraid of feeling dumb for a little while...

    What am I missing?

    325iX Turdbo RallyX/Beater/Shuttle Vehicle

    #2
    Have you tried tracing the wiring in the ECU to make sure it is right? It is possible that the wiring is to the wrong connector for spark out and not making it to the engine. Or maybe that wire is torn, or shorting out somehow.

    Your problem tells me the issue is with the ECU system since the stock ecu works that means the wiring is all good from the female engine harness to the rest of the sensors. Switching injectors, ICV, AFM, and O2 sensor back shouldn't affect the engine's spark. Is it possible one of the grounds isn't connected right? The ms unit should have a single coil driver output to the coil. Really just a positive and a negative is all that powers the coil.

    Check if the coil is getting power with the key on. Is a fuse blown or relay not working right? Are your megasquirt base settings correct (rising edge vs falling edge, trigger angle, fixed timing angle at cranking)?

    With the key in position 2 check voltage across pin 1 and 19 on the c101 connector. (19 is ground). If it is getting power, then the ecu is not triggering spark at the right time, or it is not sending the power to the right pin. Constant power should go to pin 1 for the coil and as the cap and rotor spin, it discharges as it jumps the gap.

    See below for the wiring from the ETM of 1988 e30, but should be the same starting sequence on all motronic 1.3 cars.
    Attached Files
    318iS Track Rat :nice: www.drive4corners.com
    '86 325iX 3.1 Stroker Turbo '86 S38B36 325

    No one makes this car anymore. The government won't allow them, normal people won't buy them. So it's up to us: the freaks, the weirdos, the informed. To buy them, to appreciate them, and most importantly, to drive them.

    Comment


      #3
      Thanks Ted!

      Coil is getting power. Getting voltage between pin 1 and 19 with key on. ECU is grounded to the shock tower ground that the stock ecu used. And it seems like the ECU is functioning as expected other than not producing spark. It's really strange that it did make spark a couple weeks ago on an NA tune and now will not on the same tune.

      I personally do not know too much about the base settings and what they should look like- Jay sent me a basemap to get it started and I assume it should be a good starting point.

      Jay is going to take a look at the cranking logs tonight and let me know if anything looks weird. I'm hoping something obvious will rear it's head. I'm a good mechanic but this is slightly out of my area of expertise.

      Thanks!

      325iX Turdbo RallyX/Beater/Shuttle Vehicle

      Comment


        #4
        Compare the basic settings in Tunerstudio between the two maps you have. Could be something in the setup. I would check the tooth logger as well and make sure you're getting a proper signal from your CPS.

        Comment


          #5
          Need .msq file
          @turbovarg
          '91 318is, M20B25, T3/T04E 60 trim (18psi), megasquirt, coilovers, Z3 rack, cold AC
          [b u i l d]
          [Car of the month: April 2018]

          0c8b7c9527af628a346878feb14bf757

          Comment


            #6
            Thanks guys! It looks like it's continuing to be a hardware issue. SSSquid is setting me up with a motronic setup just to get the car moving while he troubleshoots my MS some more.

            I loaded my MS with an NA basemap and tried to run my pal's bone stock e30 and no spark there either. So something is fishy with the actual board. I'll eventually buy a fresh PNP unit since my confidence in this ECU is not good at all at this point.

            Speaking of that- where does one get a MSPNP these days? DIYAT is out of stock and I'm hearing horror stories about their quality- is WHODWHO doing them anymore? I know SSSquid will have one but not for a while.

            325iX Turdbo RallyX/Beater/Shuttle Vehicle

            Comment


              #7
              the diypnp adapter board are NLA. The supplier stopped selling the connectors. k-data seems like an option though
              318iS Track Rat :nice: www.drive4corners.com
              '86 325iX 3.1 Stroker Turbo '86 S38B36 325

              No one makes this car anymore. The government won't allow them, normal people won't buy them. So it's up to us: the freaks, the weirdos, the informed. To buy them, to appreciate them, and most importantly, to drive them.

              Comment


                #8
                I had this issue last month with a whodwho. 2 replaced ignition drivers, and a bunch of headaches later, a new MS from diyautotune solved the issue.

                Comment


                  #9
                  I'm losing my mind. SSSquid built me a new motronic setup to get this running while he continues to troubleshoot my MS, and still no spark. It is making spark on the bone stock 153 ECU but obviously won't run on big injectors, no AFM, etc...

                  The unit he sent me bench tested good just like my MS but will not run my car. I have to assume it's something on my end but I can't fathom what would be going on with the car that would allow it to produce spark on one ecu and not another.

                  I did delete the OBC since it last ran but the wires are jumped at the box and the coil is getting power so I don't think that's a problem.

                  I'm starting to just throw parts at it but boy do I hate doing that- new cap and rotor today, I'll track down a coil on Monday just to start isolating things.

                  I'm seriously about to return it to stock parts just to hear it run so I can regain my sanity but I really really don't want to.

                  What the hell am I missing here?

                  325iX Turdbo RallyX/Beater/Shuttle Vehicle

                  Comment


                    #10
                    Most likely a problem with the crank sensor. The 153 may be more forgiving than the MS for a bad signal. That is the first thing I would test/replace.

                    Also be sure the crank wheel hasnt delaminated from the hub, and that the sensor gap is within spec.
                    Build thread

                    Bimmerlabs

                    Comment


                      #11
                      Motronic is much more compliant with CPS signal issues than MS is. Do what nando said.

                      Comment


                        #12
                        Thanks boys! The tooth logs looked good but I'm realizing that may or may not mean anything. Also the sensor showed correct resistance but I know from experience that sometimes that can mean nothing as well.

                        The CPS gap was good, is there even a way to adjust that on these?

                        New CPS should be here in a couple days and I'll throw a fresh coil in it tomorrow. This car could use a little love anyway for some of those parts. Keep you posted.

                        Thanks again!

                        325iX Turdbo RallyX/Beater/Shuttle Vehicle

                        Comment


                          #13
                          You can use washers to shim the CPS if the airgap is too small. You can also get probably +/- 0.2mm by loosening the two bolts that hold the bracket to the block, then push it in which direction you need as you tighten it.

                          Comment


                            #14
                            Thanks again!

                            Threw in a fresh CPS today- adjusted gap (it was pretty tight as it was), new coil just for good measure, new cap and rotor last week.

                            Still no spark on anything other than it's old 153 ECU. I don't get it. Nice strong spark when I have that ECU plugged in. It even wanted to run for a second on the 153 even on 42lb injectors, no AFM, etc...

                            I'll probably return all the electronics and injectors to stock tomorrow just so I can move it around and free up the space in my shop. I assume there's no harm in scooting it around with the turbo still plumbed in but charge piping going to atmosphere?

                            325iX Turdbo RallyX/Beater/Shuttle Vehicle

                            Comment


                              #15
                              I don't think it's going to fix your issue, but the air gap for the CPS is 1.0mm +/- 0.3mm. You don't want it too tight.

                              Comment

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