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Thread: E38 ECM Missing Open Loop F/A Tables

  1. #1
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    E38 ECM Missing Open Loop F/A Tables

    Screenshot (4).png

    With the open loop eq tables not there, what do i use to tune the afr while in open loop? Right now I'm running at .7 lambda without PE while in open loop. I don't know if this is normal or not but something tells me it shouldnt be that rich without PE active. Sometimes it happens with light throttle and low rpms as well. Causes truck to kind of stumble. AS soon as truck goes to Closed loop it goes right back to 1 EQ. Is there any way to get the open loop eq tables on my ecm?

  2. #2
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    those tables under ''open loop'' on the top left are the OL commanded fueling tables

  3. #3
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    Yes. The F/A table is just for crank fuel.

  4. #4
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    Is it normal for open loop to call for .7 eq ratio even when pe isn't active? I changed the table to. 92 in areas of operating temp and it didn't do anything.

  5. #5
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    I would like the truck to stay at stoich in closed loop and if anything when it goes into open loop get richer as More load is applied. Right now as soon as it goes into open loop even at 20%tps it calls for .85 eq minimum and when I start to lift drops to .7? I want to start tuning maf and ve but I would like to get the commanded eq to be some what around 1 and when I'm under heavy load pe take over.

  6. #6
    Tuning Addict blindsquirrel's Avatar
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    You need to post your file (and a log) if you want other people to see what you see - and maybe spot anything you might be overlooking.

  7. #7
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    Got it coming right up.

  8. #8
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    Log and Tune

    The area I'm concerns happens around 9min in log.

    just a quick explanation of what I have done to tune over stock

    Truck is a 2007 gmc sierra vmax with 6.0 L76 and 4l70e

    disabled dod. my truck had it but I deleted it. running l96 vvt cam, GM performance ls7 lifters

    changed PE

    changed fan curve to help oil temps

    changed IAT Spark by degree or two in lower IAT areas

    included stock Tune as well

  9. #9
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    It's very weird to me. I know the commanded eq ration will change some while in open loop. But I didn't think it would run that rich. I thought PE would have to be on. What's the use of pe in my case if the open loop eq is that rich?

  10. #10
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    Disable or raise the temp thresholds for COT. See if that does anything.

  11. #11
    Tuning Addict blindsquirrel's Avatar
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    Catalyst Over Temp is enabled and, suspiciously, Max Enrichment is 1.33.

    Are you mixing up Lambda with EQ? 0.7 EQ would be very lean, not rich. 0.7 Lambda would be rich.

    e: DAMMIT! Too slow...

  12. #12
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    Yes I mean lambda. When I read my aem gauge it shows .7 when under light throttle. I will turn over temp off and see what happens. I'm referring to the commanded eq ratio the truck is calling for. When I go into open loop it drops as low as .7. My gauge shows the same thing. When I let off a little it stays the same when I let almost all the way off it starts to go back to commanded eq ratio of 1 and switches back to close loop.

  13. #13
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    When lambda is that low and I apply light throttle the truck jumps and skips and I belive its because it's so rich.

  14. #14
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    Should I disable it or just go to something like 1.1 or something. Talking about catalyst over temp

  15. #15
    Tuning Addict blindsquirrel's Avatar
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    I set COT to the same as PE, don't know if that's correct/safe or not. Raising the temp thresholds and leaving the enrichment as-is is probably safer, if it's just right on the edge of triggering like that.

  16. #16
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    That would make sense why changing table didn't do anything

  17. #17
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    I set max enrich to 1.3 and changed lower temp to 1750 then 1800 then 1850

  18. #18
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    My county doesn't do emissions test about to take y pipe out and drill them suckers

  19. #19
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    I have a bunch of other questions to if I could get your info to email you back and forth would be really cool as I learn

  20. #20
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    One other question for whoever knows. When doing ve tuning speed density my truck has stabilitrack and traction control errors. I read a post about applying a traction control patch which is located under the os tab. But I don't know which one there is TCS patch 1 and TCS patch 2. Which one enables me to tune SD without stabilitrak issues