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Thread: PCM Flash to Grand-AM Cup PCM

  1. #1
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    Default PCM Flash to Grand-AM Cup PCM

    I need advise on tuning a PCM.
    We have replaced a 400CI with LS6 Heads (550HP / 510 torque) to a 383CI stroked with LS6 Heads. The new engine has lower compression (around 11 or higher) while the old was slightly higher. Same intake, injector, headers. Cam is close to the last Engine.

    I read the PCM and Changed the CI parameter and had to perform a full flash because the Grand-Am racing PCM did not have a serial number. We have not proceeded with the crank sensor learning.

    Current results: Engine cranks and idles at 1600 RPM although the desired idle is at 1000 RPM. The MAP and MAF values are within allowable range. I believe that the rational test fails which triggers the MAF P code. We do not have O2 sensors installed for sensor 2 and are disabled in PCM but we do have sensor 1 installed for both bank 1 and 2. The values at idle of the O2 sensors seems real low (.0020 mV). The command AFR is set for 13.5. The fuel learning is enabled but are resulting in 0%.

    This is a road race car and we are expecting around 510Hp with 475 foot pounds of torque.

    Question: Does low mV readings from O2 sensors reflect lean or rich? What is the best plan to start tuning?

  2. #2
    Lifetime Member mr.prick's Avatar
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    play with the desired airflow table {B4307}
    and see if that helps your idle.
    get a WBO2 for AFR, it`s bad to start a new motor overly rich.
    would you mind posting the Grand-AM Cup tune?
    512k RoadRunner Firmware 12.14R
    FlashScan V2 Bootblock V2.07.04 Firmware V2.07.22 EFILive V7.5.7 (Build 191) V8.2.1 (Build 181)
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  3. #3
    Lifetime Member 5.7ute's Avatar
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    Under 450mv is leaner than stoich, over 450 richer.
    I would do as mr.prick has stated & try lowering your desired airflow tables.
    Depending on the cam in your car using a wideband or even the narrowband sensors could be erronous due to overlap. If this is the case just give it what it wants for now.(use the bidi controls)
    The Tremor at AIR

  4. #4
    Joe (Moderator) joecar's Avatar
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    Low mV from front O2 sensors indicates lean, 450 mV indicates stoichiometric 14.7, high mV indicates rich.

    Front O2 sensors mV should look like this:
    - closed loop -> cycling from below 300 mV to above 700 mV and back again at least once per second.
    - open loop part throttle -> more or less flatlining.
    - open loop WOT-> flatlining... at WOT anything below 900 mV may be too lean.

    At WOT (which is also open loop), you want to see about 930 mV on the front O2 sensors.

    See the AutoVE tutorial: http://download.efilive.com/Tutorial...20Tutorial.pdf

    AutoVE requires a wideband O2 sensor (some, like the LC-1, support serial/digital AFR output (instead of analog) which FlashScan V2 supports).

    The idea behind AutoVE is this: the AutoVE procedure corrects the VE B0101 table; when B0101 is correct, then the OL B3605 and PE B3618 tables then produce the correct AFR (i.e. the wideband measured AFR equals the commanded AFR), which means you can set the AFR you require (i.e. something like 12.6 to 13.2 for WOT).

    After AutoVE, you can do AutoMAF which is the same procedure but with MAF enabled and B0120 set to zero; this corrects the MAF B5001 table;
    when this is done, you set B0120 back to stock.

    Before doing AutoVE/AutoMAF you may want to recalculate the IFR B4001 table to match your injectors using the spreadsheet.

    You may also want to adjust the MAF/MAP/ETC sanity tables (yes, ETC, even if you have cable thottle).

    What PCM do you have (from what donor vehicle)...?

    You may even want to run COS5 which has a MAPxRPM OL table versus the stock ECTxRPM OL table.

  5. #5
    Joe (Moderator) joecar's Avatar
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    Post some logs and tune file if possible.

  6. #6
    Joe (Moderator) joecar's Avatar
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    Is your fuel pressure regulator at the fuel rails up front (has a vacuum hose connecting it to the intake manifold) or is it in the fuel tank (no sign of it anywhere near the fuel rails; don't mistake the pulse dampner for the FPR... the pulse dampner has no vacuum hose attached to it).

  7. #7
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    Default planning to correct

    I have downloaded the AutoVE Tuning Tutorial. I plan to make revisions to the tune file tomorrow. I am going to start with lowering the desired airflow table values. After several tunes, I will post some data.

    Thanks for the advise!

  8. #8
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    Default Results-Need Help

    It seems that tuning is not may main problem. The engine is only running on 4 cylinders. After increasing RPM to over 3000 then some of the remaining four pick up. All have spark. I believe that my O2 sensors are reading so lean due to the dead cylinders.
    I have a problem with being able to Full Flash / Read / flash Cal. I always have to perform a Full Flash.

    I am attaching 3 files (2 tune files and 1 log file). My first PCM read tun file has VIN number but after I perform a Full flash the VIN number is not in the PCM.

    Again, the PCM has a Grand-Am Cup racing sticker on it but the tun file has a VIN number that matches a GM-Pontiac-Canada-1999-Trans Am Formula-LS1

    How can I get to only perform a Cal Flash so I can use other tun files that I have for a similar engine?
    Attached Files Attached Files

  9. #9
    Joe (Moderator) joecar's Avatar
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    Use the scantool to set the VIN into the PCM: Bidirectional->Change VIN.

    You mean that a cal-only flash does not work...? Can you copy the log text and paste it here.

  10. #10
    EFILive Developer Site Admin Blacky's Avatar
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    Quote Originally Posted by Rusty View Post
    How can I get to only perform a Cal Flash so I can use other tun files that I have for a similar engine?
    Download a completely stock *.tun file that matches your existing operating system 9381344 and transmission type from here: http://www.holdencrazy.com/EFILive/stockTunes.php

    Full flash that stock file into your PCM.

    Once that is complete, select the menu option: Flash->Show PCM Info... and click on the [Get Info] button. Hopefully you will see a VIN displayed, you can change it here, to your vehicle's VIN.

    If you do see a VIN, you can use the menu option Flash->PCM Security... window to change the VIN to the correct value for your vehicle.

    If you don't see a valid VIN, then please read this web page:
    http://www.efilive.com/index.php?opt...111&Itemid=121
    and send the relevant *.blx file(s) to me at paul@efilive.com

    Regards
    Paul
    Before asking for help, please read this.

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