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Thread: Fuel dynamics mafless?

  1. #21
    EFILive Reseller ringram's Avatar
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    Good luck on the o2 switch points. Ive dropped them to 50mv with no visible change to fueling.
    But I guess if you use programable sensors like the LC-1's you could get them to switch on say, 15.2:1
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  2. #22
    Lifetime Member swingtan's Avatar
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    Ringram, exactly right. Currently the switch points do not work at all in the E38. Your idea of using a programmable WB with NB output would work, but only for a fixed offset. I'd like to be able to fully utilise the CL-Mode settings to command leaner light cruise and slightly richer for things like hills. Then when it really needs more go, switch into PE mode.

  3. #23
    Senior Member alian's Avatar
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    Quote Originally Posted by swingtan View Post
    Ringram, exactly right. Currently the switch points do not work at all in the E38. Your idea of using a programmable WB with NB output would work, but only for a fixed offset. I'd like to be able to fully utilise the CL-Mode settings to command leaner light cruise and slightly richer for things like hills. Then when it really needs more go, switch into PE mode.
    Wouldnt that be great Simon.
    Ian

  4. #24
    Senior Member Wasted Income's Avatar
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    I'm seeking some clarification...

    I am running OL-SD in my turbo 5.3 setup. I am looking to improve my off-idle response, and until reading this thread, it seemed like the transient fuel tables were the ticket....but it appears that they do not work with the MAF failed??

    Do I have any other options?

    Thanks!
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  5. #25
    Lifetime Member swingtan's Avatar
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    Transients still work with the MAF disabled, you just can't fine tune them. If you check the other posts, the Transients are all based back to MAF airflow. If you fail the MAF, then it will always read "0 gm/s" or air flow, so you just B2013 to a flat line. If you want more transient fuel at WOT, then make this table all a higher number, say 0.8 or even 1. If you want less transient fuel at part throttle, then make the whole table a lower number, say 0.6.

    If you get it working well for WOT, it'll be rich at part throttle, if it's right at part throttle, it'll be lean when wide open.

    Your only other method of "fooling" the ECM into providing more accurate transient fueling would be to alter the injector timing. It's not a perfect way, but it does work. Generally speaking.....

    • Advancing injector timing will simulate an increase in transient fueling.
    • Retarding the injector timing will simulate a decrease in transient fueling.


    Interestingly, if you check the stock injector timing, it does advance the timing as RPM increase, but I don't think it's for the transients. You still need to make a couple of fairly wide reaching assumptions though....

    • Transients in HIGH PRM areas will only really be needed for WOT applications.
    • Low rpm areas will only need small amounts of transient fuel


    The break over point would be around the 2,000 RPM mark I guess, so that under that, where normal driving occurs, you have low amounts of transient fueling. Then over that, for gear changes, you have higher amounts of transient fueling. This seems to work OK, but is no substitute for the MAF signal.

    Finally, if you drive an auto, the transients are no where near as critical when compared to a manual. Unless you "flat change" in the manual, the off / on throttle event plays havoc with fueling. Transients play a big role on making gear shifts feel good in the manual.

    Simon

  6. #26
    Member TuneMaster's Avatar
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    Hi Guys, the only time i've seen this has been on cammed auto E38's that don't have a stall convertor. What i found on the dyno was the VVE cells were being hit from 800 - 2000 rpm and 70 - 105 kpa as soon as you nailed it suddenlly, the wideband here was going very lean causing surge, mis and backfire but only on quick acceleration, i tried changing dynamics but the best way was to increase VVE settings in these areas. Remember rescalling zones helps this as well. Done plenty this way and no negative feedback yet. My two cents....

  7. #27
    Senior Member Wasted Income's Avatar
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    Quote Originally Posted by swingtan View Post
    ***Lots of good info***
    Simon,

    Thank you very much. I will play with those a little bit.
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  8. #28
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    This is some valuable info. People don't seem to get the importance to dynamics section. I broke an engine because of it. I learned this tables the hard way.
    "All that is needed for the triumph of evil is that good men do nothing..."

  9. #29
    Lifetime Member mr.prick's Avatar
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    I've not seen any changes to fueling after altering the impact factor or evap time.
    Maybe it's my technique.
    How would you cure this?
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  10. #30
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    The way to cure it would be to reduce the minimum injection pulsewidth. Try that out.
    "All that is needed for the triumph of evil is that good men do nothing..."

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