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Can't pass emissions with new engine and Fast EFI 1.0

Discussion in 'FAST Support Forum' started by Harvey, Mar 10, 2017.

  1. Harvey

    Harvey New Member

    Oct 24, 2015
    Went in for emisions test with 13.5 idle afr and 13.2 cruise afr. It failed both tests.
    At 2500 rpm
    CO allowed 1.2 test 1.89
    HC allowed 220 test 154
    At idle
    CO allowed 1.2 test 3.54
    HC allowed 220 test 1148

    Changed afr to 14.5 idle and 14.0 cruise. Next test was worse! the hydrocarbons went up about
    At 2500 rpm
    CO allowed 1.2 test 2.19
    HC allowed 220 test 213
    At idle
    CO allowed 1.2 test 3.46
    HC allowed 220 test 1546

    I would have expected the HC to go down with the leaner settings but it went up!

    Any ideas what I can do to get this thing to pass. I only have 8k miles an ATK 325 HP 350.

  2. shelbydogg

    shelbydogg Member

    Jul 19, 2010
    I've never had to pass an emission test with my 48 year old cars, but I have my cruise AFR set to 15.5 and have vacuum advance hooked to manifold vacuum to advance the timing under idle and low load cruising. It takes more advance to fire a lean mixture completely before the exhaust valve opens. After adjusting AFR, drive around for a while so the mapped cells can interpolate and change to the new setting. Is this an idle sniffer test or is it the running speed test on the rollers?
  3. A A

    A A Well-Known Member

    Jun 22, 2014
    Try starting with 14.3 idle, cruise 14.7. WOT 12.8 - after resetting the ECU and inputting the other user data. It will take some driving time before the new maps build, but the plugs should start reading cleaner with the inside of the exhaust looking light gray. If the engine is timed properly, and you have no header leaks affecting the O2 sensor, this should get the CO and HC down. If you have a dual plane intake, you may need to install a single plane intake.
    Last edited: Jun 11, 2017
  4. mike64

    mike64 New Member

    Sep 17, 2015
    I passed with my 1.0 on my stock 350 by opening up my EGR valve. It ran like crap but i think lowering NOX helps lower all others. I must concur to run the vehicle for a while to get it to learn the new parameters.
  5. TurboNova

    TurboNova Active Member

    Jan 30, 2009
    Lake Havasu City AZ.. but mostly travel tuning
    Timing has a lot to do with it, good luck.
  6. Vivikos2

    Vivikos2 New Member

    May 30, 2017
    Last edited: Sep 10, 2017

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