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Thread: PE Table Not Changing Commanded

  1. #1
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    PE Table Not Changing Commanded

    OK.... something crazy is going on here I keep modifying the PE table and it does not change my Commanded AF when I do a run I even tried modifying the PE table to 13.5 and the commanded just does not change. It is stuck on 12.59. No matter what value I put in my PE table the outcome is always the same 12.60. It's driving me crazy.

    I've included screenshots and the files.

    Car: 07 Corvette Z51, M6, Callaway CAI
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    Last edited by cartman003; 01-18-2008 at 07:34 PM.
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    Joe A
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  2. #2
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    Check your open loop tables, if your open loop tables are richer than your pe tables while in open loop(wot/pe) open loop will take control.

  3. #3
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    Your MAP being set to 15 kpa and your PE enable set to 25%TPS at 4000 RPM means your in PE any time your over 4000 RPM. But...the PE ratio of 1.08 does not give enough PE and you will be running lean when you try to go to full pwoer...which is bad. Below 4000 RPM it should be following your throttle open limits, but for some reason it's reading PE enriched to 12.xx by your wideband.

    I wouldn't trust the wideband the way you have it set up.

    My advice is you should try running closed loop with PE disabled (set TPS to 100%, set kpa to 105 and set PE to 1.00). Drive the car and make sure the narrow bands are switching by logging narrowband voltages. Check your fuel trims while doing this. You do not want to see large numbers on ST or LT.

    At this point, the AFR will be 14.7 plus or minus while the narrow band sensor switches. Now read your wideband and make sure it reads 14.7 or thereabout. If it does not, you may need to calibrate the wideband inputs to agree or replace the wideband sensor.

    If you have done VE/MAF tuning with your wideband like this, your open loop is all whacked and you won't be doing yourself any good. See Bill's reply above...
    Do yourself a favor and do a narrowband MAF tune in closed loop with PE disabled and DFCO disabled. (remember to reset the fuel trims for accurate readings between adjustments). This will get you to a good baseline AFR in closed loop, then mess with the wideband and PE if the numbers start making sense.

    Sometimes, a wideband can be more trouble than it's worth...until you get it's response nailed down accurate.
    Last edited by BBA; 01-18-2008 at 08:56 PM.

  4. #4
    Senior Tuner Russ K's Avatar
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    The richer of the PE or open loop tables control the WOT commanded AFR. Make the changes as shown. Then change your PE table to 1.13 (13.0 AFR). You may have to change the IVT & Injector temp gain tables to 1.00.

    Russ Kemp
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  5. #5
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    Bill my "Open Loop EQ Ratio Gas" tables are stock and are set to 1.00 which means they are not richer than the PE commanded assuming my IVT is greater than 133.

    BBA - The PE Map of 15kpa is a stock setting I have not changed that. I did however changed the delay RPM from 5000 to 2500 with the idea that I wanted the car to go into PE at an earlier RPM. I do agree that the WB may be off because MAF Low and Hi tables where tuned and I had 0's and now running the same histogram they are saying I'm rich.

    Russ - I will make the suggested changes and see if that makes a difference.

    I can't tell you how grateful I am for all of your guy's help and suggestions.
    Last edited by cartman003; 01-18-2008 at 09:33 PM.
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  6. #6
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    Quote Originally Posted by cartman003
    Bill my "Open Loop EQ Ratio Gas" tables are stock and are set to 1.00 which means they are not richer than the PE commanded assuming my IVT is greater than 133.

    BBA - The PE Map of 15kpa is a stock setting I have not changed that. I did however changed the delay RPM from 5000 to 2500 with the idea that I wanted the car to go into PE at an earlier RPM. I do agree that the WB may be off because MAF Low and Hi tables where tuned and I had 0's and now running the same histogram they are saying I'm rich.

    Russ - I will make the suggested changes and see if that makes a difference.

    I can't tell you how grateful I am for all of your guy's help and suggestions.
    I said check your open loop tableS not table

    There are about a dozen in your calibration all of which can effect wot EQ ratio, none of which you changed which means that is where your problem is as myself & Russ pointed out.

    I've made this a sticky in hopes that it will at least help 1 other person in the future.


  7. #7
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    Quote Originally Posted by Bill@HPTuners
    I said check your open loop tableS not table

    There are about a dozen in your calibration all of which can effect wot EQ ratio, none of which you changed which means that is where your problem is as myself & Russ pointed out.

    I've made this a sticky in hopes that it will at least help 1 other person in the future.

    Bill,

    could this be the reason why my AFRs change by day from being at commanded then to go rich by few %s? I command 12.6, get it initially but when restarting later that day or next, they go to 11.6-12.

  8. #8
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    This is also something I've been working thru in the tune on my 07 Trailblazer SS learning the new os. It was my understanding that the Open Loop target afr is calculated based on the OL Gas (gear), Airflow Gain, IVT Gain, and InjTemp Gain values multipled together. Take a look at the attached log and tune. I set the IVT to 1.0 in the WOT kpa cells and the other three tables are at a location that is 1.0, so that the OL equivalence ratio should be 1.0. PE was set to an afr of 12.55. I'm seeing a commanded afr of 11.74 in 2nd gear during WOT pulls. This log doesn't show it, but I did verify in a previous log that there was no COT fuel being added. I know I'm missing something simple. Can you guys shed some light why I'm not seeing the PE afr?

    Thanks, Brian
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    Last edited by ozws6; 01-22-2008 at 04:43 PM.
    01 WS6 with a little whistle...
    07 TBSS
    98 GTP intercooled & pullied

  9. #9
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    yeah but then you still have cat over temp enabled.

  10. #10
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    Quote Originally Posted by Bill@HPTuners
    yeah but then you still have cat over temp enabled.
    Bill, that is correct the COT was not disabled. I logged the CAT Temps the day after I had made the previous log and both never exceeded 1485F during the 2nd gear pulls. Looking at the COT thresholds, 1661F is the lowest and I'm assuming that value has to be exceeded for COT enrichment to occur. Is that correct? If not then maybe thats what is going on.

    Attached is the 2nd log with the exact same tune as before. Ignore the wideband values in this log as the wideband wasn't on the truck.

    Thanks again, Brian
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    01 WS6 with a little whistle...
    07 TBSS
    98 GTP intercooled & pullied

  11. #11
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    Then you might want to consider logging cat over temp protection on/off status bit to rule that out.

  12. #12
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    After putting all the open tables to 1.0 I was finally able to get the car to run whatever A/F ratio I commanded. I guess my next question is what are the disadvantages to having all these carefully constructed tables to 1.0?

    Once the car is back in CL what tables will effect how PE is calculated (besides COT)?
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  13. #13
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    Cart, you dont have to set them ALL to ALL 1.0's. You can be slick. Keep the "warming up" areas stock, then get anything over an intake valve temp of 140 and coolant 176 or so to 1.0

  14. #14
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    This might be the reason my car is not adjusting to the AFR's I am commanding. I will check it out tonight when I finish work. Thank you for your help.

    Quick question I know you said open loop tables and there are about a dozen of them. Can anyone point out which tables they are exactly that I need to adjust. The names of the tables. Im sorry I'm new to this tuning and I am willing to learn but I need some guidance in the right direction to begin.