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Thread: Emissions readiness...04 GTO w/2bar OS

  1. #1
    Tuner in Training
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    Emissions readiness...04 GTO w/2bar OS

    Will the emissions readiness tests ever complete with a 2 bar OS SD tune (no MAF?)

    Ive got my cats back in to pass the sniffer, but my "Once per trip tests" wont complete, even when I follow the standard GM directions to make them complete.

    This is an 2004 GTO with the HPTuners 2 Bar OS, which doesn't use the MAF at all (and its not even physically installed anymore)
    Unfortunately the amount of mods on this car will prevent going back to a stock tune even if I put a stock 1bar MAP back in it.

    Ive double checked all the DTC's:
    cat efficency, all the O2 sensor codes, etc, all are like stock except the MAF fail one which kicks it into speed density mode.

  2. #2
    Tuning Addict WS6FirebirdTA00's Avatar
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    post the tune and the screen shot of the readiness codes
    Sulski Performance Tuning
    2000 WS6 M6 - LS6 (long block, refreshed top end), 10.8:1 CR, 90 mm ported FAST, Exo-Skel, 227/232 cam, QTP HVMC, EWP, GMMG, 9" w/4.11s
    2018 Sierra SLT 5.3L A8 - Airaid intake tube, GM Borla catback, L86 Intake/Ported TB

  3. #3
    Senior Tuner Frost's Avatar
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    Set SES to disable for all but set to fail at first error.

    Here is the "drive cycle" to complete readiness:



    General Motors (specific) OBD II Drive Cycle


    Performing a GM OBDII Driving cycle:

    1. Cold Start. In order to be classified as a cold start the engine coolant temperature must be below 122°F (50°C) and within 11°F (6°C) of the ambient air temperature at startup.
    Do not leave the key in prior to the cold start or the heated oxygen sensor diagnostic may not run.
    2. Idle. The engine must be run for two and a half minutes with the air conditioner on and rear defroster on. The more electrical load you can apply the better. This will test the O2 heater, Passive Air, Purge "No Flow", Misfire, and - if closed loop is achieved- Fuel Trim.
    3. Accelerate. Turn off the air conditioner and all the other loads and apply half throttle until 55mph (88km/hr) is reached. During this time the Misfire, Fuel Trim, and Purge Flow diagnostics will be performed.
    4. Hold Steady Speed. Hold a steady speed of 55mph (88km/hr) for 3 minutes. During this time the O2 response, air Intrusive, EGR, Purge, Misfire, and Fuel Trim diagnostics will be performed.
    5. Decelerate. Let off the accelerator pedal. Do not shift, touch the brake or clutch. It is important to let the vehicle coast along gradually slowing down to 20 mph (32km/hr). During this time the EGR, Purge and Fuel Trim diagnostics will be performed.
    6. Accelerate. Accelerate at 3/4 throttle until 55-60mph (88-96 km/hr). This will perform the same diagnostics as in step 3.
    7. Hold Steady Speed. Hold a steady speed of 55mph (88km/hr) for five minutes. During this time, in addition to the diagnostics performed in step 4, the catalyst monitor diagnostics will be performed. If the catalyst is marginal or the battery has been disconnected, it may take 5 complete driving cycles to determine the state of the catalyst.
    8. Decelerate. This will perform the same diagnostics as in step 5. Again, don't press the clutch or brakes or shift gears.
    Steve Williams
    TunedbyFrost.com


  4. #4
    Tuner in Training
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    Im familiar with the drive cycle. Anyways, it passed the test, apparently they didn't care about the readiness tests as long as the cats are in place and the sniffer checks out.

    Txs for replies.

  5. #5
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    Quote Originally Posted by Frost
    General Motors (specific) OBD II Drive Cycle

    Performing a GM OBDII Driving cycle:

    1. Cold Start. In order to be classified as a cold start the engine coolant temperature must be below 122°F (50°C) and within 11°F (6°C) of the ambient air temperature at startup.
    Do not leave the key in prior to the cold start or the heated oxygen sensor diagnostic may not run.
    2. Idle. The engine must be run for two and a half minutes with the air conditioner on and rear defroster on. The more electrical load you can apply the better. This will test the O2 heater, Passive Air, Purge "No Flow", Misfire, and - if closed loop is achieved- Fuel Trim.
    3. Accelerate. Turn off the air conditioner and all the other loads and apply half throttle until 55mph (88km/hr) is reached. During this time the Misfire, Fuel Trim, and Purge Flow diagnostics will be performed.
    4. Hold Steady Speed. Hold a steady speed of 55mph (88km/hr) for 3 minutes. During this time the O2 response, air Intrusive, EGR, Purge, Misfire, and Fuel Trim diagnostics will be performed.
    5. Decelerate. Let off the accelerator pedal. Do not shift, touch the brake or clutch. It is important to let the vehicle coast along gradually slowing down to 20 mph (32km/hr). During this time the EGR, Purge and Fuel Trim diagnostics will be performed.
    6. Accelerate. Accelerate at 3/4 throttle until 55-60mph (88-96 km/hr). This will perform the same diagnostics as in step 3.
    7. Hold Steady Speed. Hold a steady speed of 55mph (88km/hr) for five minutes. During this time, in addition to the diagnostics performed in step 4, the catalyst monitor diagnostics will be performed. If the catalyst is marginal or the battery has been disconnected, it may take 5 complete driving cycles to determine the state of the catalyst.
    8. Decelerate. This will perform the same diagnostics as in step 5. Again, don't press the clutch or brakes or shift gears.
    Would this drive cycle apply to my '99 S10, too? I just swapped
    intakes and the Catalyst and Evaporative System tests have not
    yet turned to Complete. My cats were not touched and the evap
    solenoid and valve are still connected to the intake as prior to the
    swap. I see catalyst mentioned above, but I don't see the evap?
    I have not yet done a steady speed drive of 55mph yet, however.

  6. #6
    Senior Tuner Frost's Avatar
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    Yeah that should be relevant to a 99 S10 as well.
    Steve Williams
    TunedbyFrost.com