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enabling rear o2 sensors for catalyst monitor

Discussion in 'Tuning À la carte' started by keith89, Sep 18, 2019.

  1. keith89

    keith89 Well-Known Member Established Member

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    the rear o2 sensors on my tune were previously shut down in the sct tune. I have since converted to the quarterhorse. The car is an 04 GT has cats and i have replaced all 4 oxygen sensors since they were the originals at 95k miles.

    I want to make sure i turn everything back on needed to set the catalyst monitor. So far i have changed to:
    HEGO - Rear > Downstreat Rear HEGO Heater (1&2): 1
    HEGO - Rear > Rear HEGO Sensor Input: DUAL BANK
    Emissions - Catalyst Monitor > Catalytic Converter Temperature Input: Enab led

    The only other things I have noticed different from a stock tune are:
    Emissions - Catalyst Montior > Different Temp Average for Ambient and ACT: 40 insetead of 8
    Emissions - Catalyst Montior > Fan Control ACT Delta to Resume Changing: 10 instead of 2

    Is there anything else I should check?

    Also does the Evap monitor need to complete before the Catalyst?

    The Catalyst and Evap monitors are taking a while to set. I fixed a leak in the evap line last week and have driven 60 miles since(i probably need to do 1 or 2 more cold cycles). All the monitors on my Cobra set within 20 miles. I'm thinking it may be because the GT is an auto. Even the o2 sensor, heaters, and egr took quite a bit of time to set on the GT.
     
  2. slo984now

    slo984now AKA 01yellerCobra Established Member

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    Does Quarterhorse have the barometric measurements? That was the last thing I needed to change in my tune to get the monitors to set. SCT sets them to 27 I think. I reloaded both of them to stock and it set the monitors.
     
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  3. decipha

    decipha Active Member Established Member

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    quarterhorse is the hardware not the software

    what software are you using?
     
  4. keith89

    keith89 Well-Known Member Established Member

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    Binary editor
     
  5. keith89

    keith89 Well-Known Member Established Member

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    it does. max is set to 30 minimum at 27
    it looks like stock should be 30.5 max and 18 min
     
  6. slo984now

    slo984now AKA 01yellerCobra Established Member

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    My experience with it was that I couldn't get the EGR and catalyst monitors to set. I ended up loading a base tune and they set quickly. Someone on here told me the barometric stuff needed to be set to stock. So I loaded it back to stock on the tune I normally run and within a few miles everything set. I was watching the P1000 on my Aeroforce gauge. Once it went away I was pretty happy.

    Now I've been told they'll never clear with an aftermarket MAF. Something about it not hitting the right values. I'm switching to a BA3000 and I have those set to stock to see what happens when I start driving it again.
     
  7. blownstang4.6

    blownstang4.6 Active Member Established Member

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    Egr and Evap have to set before catalyst will.
     
  8. keith89

    keith89 Well-Known Member Established Member

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    All the other monitors other than evap and catalyst set. The EGR and O2 sensors took longer than expected to set but they evdentually did. Unfortunlately, I can't drive on a base tune de to the KB2.1 and supporting mods. I'm going to try a few more drive cycles concentrating on the evap and catalyst driving conditions before changing the barametric pressure scalars.

    What do these scalars do? the description was kind of vague and I do not know the fll downstream effect of changing them.
     
    Last edited: Sep 18, 2019
  9. slo984now

    slo984now AKA 01yellerCobra Established Member

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    I really don't know. All SCT says is to set them to 27 I think. Which causes the monitors to not set. Putting them back to stock helped the monitors set quickly in my case. And I haven't seen an ill effects. I would set them back to stock and see what happens. In my case the evap was the easiest to set.
     
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  10. keith89

    keith89 Well-Known Member Established Member

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    Based on the descriptions in BE, it sets the min and max barometric pressure where the ecu will try to make adjustments(adjustments for altitude basically). I don't see why they would need to change this unless the inferred barometric pressure function is prone to errors.
     
  11. decipha

    decipha Active Member Established Member

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    its used for inferred baro pressure

    if you dont dial in the inferred load table bp can go ape shit and throw fuel and spark around if not setup properly
     
  12. keith89

    keith89 Well-Known Member Established Member

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    That makes sense but assuming the inferred load is being calculated correctly why would the max and min barometric pressure need to be changed?
     
    Last edited: Sep 18, 2019
  13. decipha

    decipha Active Member Established Member

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    it wouldnt

    its only an issue if u dont dial in inferred load

    If i had to guess i would assume it originated back in the fox body days. They had a bap sensor. If the bad sensor freaked out which ive seen numerous times it can add 12 degrees of timing at wot.

    if sct seen that happen to i would assume they would recommend to clip barometric pressure so it couldnt do that since sct had no obd-1 logging abilities
     
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  14. keith89

    keith89 Well-Known Member Established Member

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    As always, thank you, Decipha! Your vast knowledge has me more comfortable with tuning my own cars.
     
  15. keith89

    keith89 Well-Known Member Established Member

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    Changing barometric pressure scalars back to stock values worked! Evap set in 15 min just before evap and 02 heater/signal monitors. Catalyst still hasn't set but it will pass inspection with 1 not ready.

    I took it in for inspection(had scanned it just before getting in line and no codes). As soon as they restarted the car to scan the monitors, the CEL came on and P0190 popped up. I'm thinking the frps may have been going out for a while as the car would occasionally die right after starting. It runs fine otherwise. Fuel pressure PID reads fine when datalogging, so it may be an intermittent thing. I have to find the spare FRPS I've been storing for the Cobra.
     
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  16. keith89

    keith89 Well-Known Member Established Member

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    replaced the FRPS. Does anyone know how long it may take the P0190 to reset on its own? There was no fuel smell in the vacuum line so i suspect the sensor electronics were going bad. Is it a certain number of key on/off cycles that triggers the code? I'd rather not reset the CEL and have to go through the emissions drive cycle again to get it inspected. I will if i have to though.
     

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