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m20 with megasquirt idle and rev issues

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    m20 with megasquirt idle and rev issues

    I have an 87 e30 with the e bottom end and i head with a turbo ans wasted spark ignition run by megasquirt ems pro which is based of the ms1/extra setup. I was able to get the car up and running and seems to start every time whether hot or cold but am still having a few issues that i am unsure which to tackle first and what direction to go with them.

    first off i cant figure out how to get my idle below 1100 rpm, idk where the target idle setting would be? also it runs super rich no matter what I do which may be because my injectors are to big for the application or i just need to mess with the ve table some more?
    second cant rev past 1700 rpm, acts like its hitting some type of rev limit or 2step type of sound,
    third i have had 2 set of ls truck coil die on me and i havent even driven the car yet, is there a setting i have that could cause this? too much or too little dwell? incorrect timing? plug gap?
    fourth and last may be the result of above or the cause, turbo manifold seems to get super hot at idle, glows red as well as turbo hot side , gets hotter longer I idle it , coolant temps are a little hot as well .

    the spark and ve tables i copied from a thread on e30tech from what i read they should work as a ood starting point/base maps
    Any input is greatly appreciated

    I have a screenshot of the wheel decoder settings and my current msq attached to my thread on msextra forums

    http://www.msextra.com/forums/viewtopic.php?f=4&t=66679

    current mechanical setup
    m20 from 325e 885 "i" head fresh rebuild with arps
    ebay manifold and gt35 turbo
    3 inch exhaust with glasspack muffler
    extrnal wastegate
    fuel cell with inline pump rated 5-600 hp

    #2
    If you're burning up coils something is very wrong, your dwell settings seem reasonable, but without knowing more about your setup it's not possible to know if the output inverted setting is correct. If this setting is wrong it can kill ignition coils, if it is right there may be a wiring issue. The wheel decoder settings also seem weird, how did you arrive at these settings? A problem with either of these areas will cause all sorts of problems, including refusing to rev and dumping burning fuel into the exhaust and making it glow red hot. Depending on the injectors you have, it may not be possible to have a reasonable idle AFR, I see you're using 80lb injectors - even the best 80lb injectors will be limited by minimum pulse width when you are idling, once you drop below minimum pulse width you will see probably see issues with inconsistent afrs and surging. As for using someone else's table as a base, that's of limited usefulness unless your setups are close to identical. A couple of other issues I can spot are that you should recalculate your required fuel number based on your engine's parameters, it doesn't seem right, and (this is important) reduce EGO control authority to 0 while doing initial tune; it will only cause you issues at this stage to run in closed loop.
    Last edited by varg; 07-21-2017, 02:55 PM.
    @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


      #3
      Originally posted by varg View Post
      If you're burning up coils something is very wrong, your dwell settings seem reasonable, but without knowing more about your setup it's not possible to know if the output inverted setting is correct. If this setting is wrong it can kill ignition coils, if it is right there may be a wiring issue. The wheel decoder settings also seem weird, how did you arrive at these settings? A problem with either of these areas will cause all sorts of problems, including refusing to rev and dumping burning fuel into the exhaust and making it glow red hot. Depending on the injectors you have, it may not be possible to have a reasonable idle AFR, I see you're using 80lb injectors - even the best 80lb injectors will be limited by minimum pulse width when you are idling, once you drop below minimum pulse width you will see probably see issues with inconsistent afrs and surging. As for using someone else's table as a base, that's of limited usefulness unless your setups are close to identical. A couple of other issues I can spot are that you should recalculate your required fuel number based on your engine's parameters, it doesn't seem right, and (this is important) reduce EGO control authority to 0 while doing initial tune; it will only cause you issues at this stage to run in closed loop.
      thanks for all the great info and guidelines. as for inverted or not my research has yielded that it is supposed to be set to yes however here is a little more info on my setup. m20 "e"bottom end with 885 head. 60-2 crank wheel from later m20 or m50/m52 ( cant remember what it came off of ) and vr crank sensor from same vehicle . 6 ls style coils wired in waste spark setup, spark a to cylindr 1 & 2, spark b to cylinder 5 & 2 and spark c to cylinder 3 & 4 since firing order is 153624 in tunerstudio rpm seems to be accurate as well as on my tachometer, 200 cranking and been idling around 1100. The wheel decoder settings came from the wheel decoder spreadsheet in the megamanual. with cylinder 1 at tdc the vr sensor is aligned with tooth 15 on the crank wheel. Im not too concerned about idle afr , if it runs rich because the injector are big then it can run rich, more concerned with the rpm being so high and not going down. as for minimum pulse width is there a spec for it for my specific injectors or is it more of a trial and error thing? The tables i copied the person was running near identical mechanical setup with the exception of injector size. they had 42lb installed. for req fuel confirmed all inputs into the calculator are correct and it comes out with 3.6ms , may have adjusted that by mistake before. will this need to be different since i swapped the heads and im using displacemet value based on stock e motor? i have changed the ego control authority down to 0 to avoid closed loop. Thanks again for your input it is greatly appreciated.

      Comment


        #4
        I've used output inverted more often than not but I don't know the ins and outs of EMS Pro hardware, with what kind of drivers it uses. It's just odd to me that you're killing coils like that, there has to be something very wrong and that was my first thought. If the wheel decoder settings came from the spreadsheet, they should be fine, they just looked odd to me. As for minimum injector pulsewidth, there will be a published spec for that with pretty much any injector from a reputable manufacturer along with the opening time with respect to voltage, but finding where you run into minimum pulsewidth is a trial and error process. As for displacement in the req fuel calculator, just use regular M20B27 displacement, the combustion chamber volume changes compression ratio but not swept volume.

        Other than idling high and not revving, does it idle smoothly? How hot do your coils get when you run it briefly? Have you inspected the crank sensor waveform in the tooth logger?

        (EDIT)

        Originally posted by mccarthy69 View Post
        6 ls style coils wired in waste spark setup, spark a to cylindr 1 & 2, spark b to cylinder 5 & 2 and spark c to cylinder 3 & 4 since firing order is 153624
        A-1/6, B-5/2, C-3/4?
        Last edited by varg; 07-24-2017, 06:27 PM.
        @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


          #5
          Originally posted by varg View Post
          I've used output inverted more often than not but I don't know the ins and outs of EMS Pro hardware, with what kind of drivers it uses. It's just odd to me that you're killing coils like that, there has to be something very wrong and that was my first thought. If the wheel decoder settings came from the spreadsheet, they should be fine, they just looked odd to me. As for minimum injector pulsewidth, there will be a published spec for that with pretty much any injector from a reputable manufacturer along with the opening time with respect to voltage, but finding where you run into minimum pulsewidth is a trial and error process. As for displacement in the req fuel calculator, just use regular M20B27 displacement, the combustion chamber volume changes compression ratio but not swept volume.

          Other than idling high and not revving, does it idle smoothly? How hot do your coils get when you run it briefly? Have you inspected the crank sensor waveform in the tooth logger?

          (EDIT)


          A-1/6, B-5/2, C-3/4?
          that was a typo on the coil setup A-1/6, B-5/2, C-3/4 is correct.
          it idles fairly smooth it can get a little lumpy at times but for the most part its consistent . coils seem to be about the temperature of the valve cover theyre attached to , they dont appear to me excessively hot, havent lost any more these last few tines i had it running (cheap coils maybe) got some decent aftermarket from worldpac on there now. what should i look for hen checking the tooth logger?
          i think we are on to something with ignition being too retarded and burning fuel into exhaust. so far i have confirmed cam timing is dead on , spark plug gap is correct and have all 6 coils firing currently .
          Some more checks - with cylinder 1 tdc on compression stroke my vr sensor lines up with tooth 16 on the 60-2 wheel. using the wheel decoder spreadsheet i get the settings that are entered in my msq. with the engine at tdc i made a mark on the tooth 16 that it aligned at tdc so it will show up with a timing light. at idle i am commanding 10*btdc timing but the timing light is lighting when tooth 18/19 are aligned with the vr sensor which to my understanding means the timing is retarded, correct? on a 60-2 wheel each tooth is approx. 12* so that means i am running about 12*ATDC and most likely burning fuel is getting into the exhaust . how would I go about to correct this ? i set the ego correct off and made the turn on prameters so far out it will stay in open loop, also i dont have a knock sensor and the table is disabled so that shouldnt be pulling timing. is there something im missing that could be doing that? hoping with this straightend out i can actually have the car running and start tuning for real.

          i attached my msq, the spark map is set to 10* just for testing purposes at the moment
          drew a picture of the 60-2 setup (i apologize for the sloppyness but im no artist)

          thank you

          the uploads keep failing , i have them posted up here on msextra forums
          http://www.msextra.com/forums/viewto...507832#p507832

          Comment


            #6
            The tooth logger should show pulses of relatively even height with a spike where the missing tooth is, have a look at this for more info; https://www.diyautotune.com/support/...megasquirt-vr/

            You seem to be on the right track here, when testing fixed timing with the timing light, the TDC tooth would only line up with the crank sensor with no ignition advance. With ignition advance of 10 degrees btdc and tooth 16 at 0 degrees (counting teeth counter clockwise), the crank sensor should be roughly over tooth 14. There is a significant difference between the two trigger wheels which will fit an M20;


            Based on what you've told me, I think your trigger settings are wrong. If you have the M20B25 wheel and crank sensor bracket, the tooth #1 angle is 84 degrees, this is the setting I use with my M20. With the other wheel pictured above, it would be tooth 54. Punch tooth 14 into the spreadsheet and use those settings, then verify with a timing light.
            Last edited by varg; 07-27-2017, 11:24 AM.
            @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


              #7
              Check your coolant temp sensor wires too. I used the stock sensor and chaffed wires were creating false temperature dops with the engine adding fuel than needed. Idle control improved agreat deal after the problem was fixed..

              Comment


                #8
                Originally posted by varg View Post
                The tooth logger should show pulses of relatively even height with a spike where the missing tooth is, have a look at this for more info; https://www.diyautotune.com/support/...megasquirt-vr/

                You seem to be on the right track here, when testing fixed timing with the timing light, the TDC tooth would only line up with the crank sensor with no ignition advance. With ignition advance of 10 degrees btdc and tooth 16 at 0 degrees (counting teeth counter clockwise), the crank sensor should be roughly over tooth 14. There is a significant difference between the two trigger wheels which will fit an M20;


                Based on what you've told me, I think your trigger settings are wrong. If you have the M20B25 wheel and crank sensor bracket, the tooth #1 angle is 84 degrees, this is the setting I use with my M20. With the other wheel pictured above, it would be tooth 54. Punch tooth 14 into the spreadsheet and use those settings, then verify with a timing light.
                I'm the same setup as the OP, 2.7 with 885 and a "i" 60-2. I am Ms2 and my settings are, falling edge, going high, tooth angle 84. Does that sound right? I ran tooth angle 97 for a while and it was sluggish.

                Sent from my SAMSUNG-SM-G935A using Tapatalk
                - AXIS POWERS - 2JZ E30 Build
                Interested in drifting in the ArkLaTex? Join us!
                318Racing.org

                Comment


                  #9
                  Originally posted by SLEEPYDUB View Post
                  I'm the same setup as the OP, 2.7 with 885 and a "i" 60-2. I am Ms2 and my settings are, falling edge, going high, tooth angle 84. Does that sound right? I ran tooth angle 97 for a while and it was sluggish.

                  Sent from my SAMSUNG-SM-G935A using Tapatalk
                  You need to verify your timing with a timing light.

                  Comment


                    #10
                    Originally posted by Digitalwave View Post
                    You need to verify your timing with a timing light.
                    I did, mine is at 83

                    Sent from my SAMSUNG-SM-G935A using Tapatalk
                    - AXIS POWERS - 2JZ E30 Build
                    Interested in drifting in the ArkLaTex? Join us!
                    318Racing.org

                    Comment


                      #11
                      If you verified it with a timing light, then it's right.

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