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ATS Correction

Discussion in 'FAST Support Forum' started by lazaris, Apr 10, 2018.

  1. lazaris

    lazaris Member

    Joined:
    Jul 28, 2011
    If I'm adding 5% fuel at 200* inlet temperature and I have closed loop enabled with an A/F of lets say 11.5:1, won't the O2 try to remove the 5% that's added at 200* to match the target of 11.5:1 ?
     
  2. lazaris

    lazaris Member

    Joined:
    Jul 28, 2011
    Bump.
     
  3. Fastmanefi

    Fastmanefi Active Member

    Joined:
    Jun 4, 2011
    Location:
    Sonora, CA
    That's correct. FAST does not provide a Closed Loop override for ATS. They do for CTS however.
     
  4. Fastmanefi

    Fastmanefi Active Member

    Joined:
    Jun 4, 2011
    Location:
    Sonora, CA
    You could use Aux3 Out to trip a relay which would add a shunt resister around the CTS sensor. That would trick the ECU into thinking the CTS temp was higher which would allow you to use the Target AF Offset vs CTS table to richen the Target AF.
     
  5. lazaris

    lazaris Member

    Joined:
    Jul 28, 2011
    Ok thanks Rich. I guess you would have to run open loop to take advantage of ATS then? What about individual cylinder fuel enrichment? If you add 5% fuel to a cylinder will the others be trimmed due to the added fuel that the o2 should be picking up from the enriched cylinder?
     
  6. Fastmanefi

    Fastmanefi Active Member

    Joined:
    Jun 4, 2011
    Location:
    Sonora, CA
    No. You would leave it in Closed Loop but the Target AF would be changed so Closed Loop wouldn't back out the enrichment.

    The only correct way to set the individual cylinder control is with 8 widebands.
     
  7. lazaris

    lazaris Member

    Joined:
    Jul 28, 2011
    I meant if you still tried using ATS for enrichment without closed loop, I['m guessing that's another way around it..

    I do it through plug read. I was curious how the fueling to the other cylinders get modified with the enrichment to the 1 cylinder. In closed loop wouldn't a percentage a fuel be taken away from the other 7 because the o2 is seeing richer condition from the added fuel to the 1 cylinder?
     
  8. Fastmanefi

    Fastmanefi Active Member

    Joined:
    Jun 4, 2011
    Location:
    Sonora, CA
    Yes, you could use the ATS in open loop, no problem.

    And yes, the wideband is seeing the result of 4 cylinders of the engine. If the cylinder you are adjusting is on that side, then the O2 correction will affect the entire fuel table. The point of individual cylinder corrections is to "balance" the burn between cylinders not to richen or lean the tune.
     
  9. lazaris

    lazaris Member

    Joined:
    Jul 28, 2011
    Great explanation. Thanks Rich.
     

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