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Thread: Help with my Turbo m20 tune

  1. #1
    Join Date
    Aug 2012
    Location
    CT
    Posts
    3,880
    My Cars
    Twin turbo LS E36 M3

    Help with my Turbo m20 tune

    Whats up guys, i just got done with my m20 build and am having some issues that no matter what i do, i cant get rid of.

    The setup
    1988 325 with super ETA
    super ETA stock block, oringed and head studded
    I head with shrick cam, slight port job, port matched I intake manifold and I TB
    61mm inducer turbo, ebay probably
    real tial wastegate, tial knock off BOV

    DIYautotune DIY PNP megasquirt kit
    60lb bosch, 255 walboro fuel pump, both brand new
    innovative LC1 with brand new sensor
    stock ignition with NGK bpr7es and MSD coil

    running on spring pressure (14lbs)


    Ok so heres the deal. No matter what, there is a random lean spot when WOT in boost. Wether its 3200 or 5200, it will always spike lean and break up. I can rarely get threw a gear under full throttle. The car is real choppy at cruising speeds even with a 13.5AFR. My logs are telling me its going lean, but with the partial throttle choppy-ness, im leaning towards an ignition break up.

    i took some screen shots of my logs and maps. Let me know if i can provide any more info. The car is super fast until it breaks up. Its not showing any signs of detonation on the plugs and sounds great (until it breaks up)












  2. #2
    Join Date
    Nov 2007
    Location
    Western New York
    Posts
    20
    My Cars
    Turbo S50 swap e30
    No sync losses showing up? What is the general health of the ignition system (new, relatively) ? Do you have a stock coil to double check the MSD coil? Have you verified with a timing light that the timing is set properly? Also, make sure all the decel and accel enrichments are off while you go through the initial tuning (or is this an old tune that has run properly in the past)?

    Has it been sitting all winter? I had an issue last where when I brought my car out in the spring it did the same thing until I reloaded the calibration. Right or wrong I did not think much more of it.

  3. #3
    Join Date
    Aug 2012
    Location
    CT
    Posts
    3,880
    My Cars
    Twin turbo LS E36 M3
    Its funny you mention the accel and del enrichment because i see it blinking when its breaking up.

    I have a COP conversion, im waiting on the drivers from DIYautotune to install it BUT i did try 2 sets of wires, both of witch drove perfect on stock cars but are both used. 1 set has about 10k miles, and that inlcudes the cap and rotor. The cap and rotor do look shaky in condition, but are bosch and arent older then 6 months.

    Car is my daily. It was 100% stock running on the megasquirt and MSD coil 5 days ago. I had it running like that for about 2 months while i got the rest of the kit together. But i do have the stock coil.

    I actually tuned it once, and couldnt get a clean pass, and then made a 2nd calibration from scratch and ended up with the same results.

    What should the base timing be? 10degress IIRC, right?

  4. #4
    Join Date
    Nov 2007
    Location
    Western New York
    Posts
    20
    My Cars
    Turbo S50 swap e30
    I set my timing to 0 deg in the idle timing table or base table, (make sure you know what table you are running on) and check it vs the TDC mark.

    So it was running fine before putting the turbo stuff on? Do you have misfire above 3200 rpm regardless of engine load?

    You do have some big jumps in your VE table that I would not expect to see. Try and smooth some of that out and see where it gets you. Otherwise I would take a real hard look at the fuel pressure regulator and all your vacuum/boost lines.

  5. #5
    Join Date
    Aug 2012
    Location
    CT
    Posts
    3,880
    My Cars
    Twin turbo LS E36 M3
    ok, i smoothed it out pretty good. Ill have to check if it misses above 3200. The tooth logger doesnt show anything abnormal, but ill log it when i try the accel enrichment turned off.

    So today ill be trying the old coil and a different FPR

  6. #6
    Join Date
    Aug 2012
    Location
    CT
    Posts
    3,880
    My Cars
    Twin turbo LS E36 M3
    it was the accel enrichment setting set too sensitive. Also it was still set for map based enrichment, due to the fact it wasnt changed since adding the TPS during the build.

    This is why you shouldnt rush at the end of a project because your so excited to go rip it. lol

    Too sensitive



    turned off

  7. #7
    Join Date
    Nov 2007
    Location
    Western New York
    Posts
    20
    My Cars
    Turbo S50 swap e30
    Yep - got to be careful with the transient stuff until your base table is pretty good. Good to hear you got it sorted out.

  8. #8
    Join Date
    Aug 2021
    Location
    denver co
    Posts
    2
    My Cars
    1988 bmw 325 super eta
    can you post your maps now that its sorted? i have same setup similar isssues.

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