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Thread: LS2 swap issues

  1. #1

    LS2 swap issues

    Hey all, I finally got my '72 Cutlass with a 370" LS2(LS3 topend, LS9 cam, 9.5:1cr)/6L80E swap running. The ECM is straight from PSI and has their base tune for a 2008 C6 Vette, the only change I've made to it is to turn off the fan trouble codes. I'm intermittently getting a P0101 MAF error (pending), even after swapping out the MAF. Plus, I'm seeing a P0315 CPS error, though I can't run the re-learn even after the DTCs are cleared and nothing is being reported. Soon enough the P0315 pops up again and I still am unable to do the relearn because of trouble codes. I was hoping dip my toes into tuning with this setup but have immediately run into a roadblock lol I'll attach the tune and log files, hopefully someone can get me going in the right direction. Thanks, James
    Cutlasslog.hpl
    CutlassStocknofans.hpt

  2. #2
    Im curious to see what others have to say about this but I dont think you will be able to fix the P0315 because you wont be able to perform the crank relearn. Even with the codes cleared, Ive never been able to successfully do a crank relearn. The only input missing that the ECM wants to see is a parking brake input from the body module.

    Are you using an LS3 MAF sensor and is the base tune correct for that style sensor. Look at your receipt (not the instruction sheet) from PSI and under MAF it should say which style sensor. Some of these MAP and MAF performance codes are almost impossible to fix due to mixed and matched parts, sensors and intake tube design. You can go in a change the test parameters for a few of these performance related codes and that will keep the code from setting.

    Also double check the flow rating on your injectors and make sure it matches your tune. PSI gets this wrong a lot! Ive used about 50 ECM's from PSI and they make a mistake on a tune about 30% of the time, either wrong parameters or codes not turned off that should be off.

    Good luck.

  3. #3
    Thanks WAK, yes, I'm using an LS3 MAF and factory LS3 injectors, IFRvsPD looks good (factory LS3 C6) in the tune. The original MAF was purchased from PSI at the same time as the harness, ECM and pedal though I don't think I have the receipt any more. It's been approx 6 years and 3 or 4 moves since I bought it though it may turn up after some more digging. The MAP is also a new, AC Delco factory LS3 unit. I've noticed on other peoples logs the Mass Airflow lb/min (SAE) reads half to a third of what mine is at idle. From what I'm reading the tubing my MAF is in needs to be 4", currently it is 3". Would that alone cause the funky readings? If so, are there some changes I can make in the tune to compensate or would I be better off going with 4"?