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Thread: How Do You Achieve Zero Fuel Consumption On Deceleration?

  1. #41
    EFILive Distributor dfe1's Avatar
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    Based on my experiences, Tordne is absolutely correct, the M6 DFCO settings control fuel cut while shifting gears and the clutch is depressed. I use some fairly agressive settings with my 01 Corvette, so they are available on US-built vehicles. As for popping being caused by fuel entering the converters, I don't see how that can happen if you cut the fuel. I don't notice any popping when I back off the throttle. As for running the mixture so rich that it can't burn-- that's a good way to kill the converters.
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  2. #42
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    well your settings seem to work nice but I might look on my logs to see if I could increase the map trigger points. Certainly no popping in the cats - on the default factory there was

  3. #43
    Lifetime Member mistermike's Avatar
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    The GTO seems to produce a bit of "popping" on decel, mostly when long tube headers are installed. I can only assume this is due to the delay factors in the factory DFCO calibration allowing a certain amount of fuel to be "sucked out" of the injectors before DFCO engages. This mixture is naturally quite rich. Once DFCO kicks in, the mixture transitions to an A/F range where it can easily self ignite, hence the popping. I would guess this is occurring in the header tubes, as opposed to the cats. Completely defeating DFCO seems to eliminate this, so I can only assume the decel mixture remains too rich to self ignite in the headers, but rather is burned off in the cats, undoubtedly shortening their life and tossing fuel economy out the window.
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  4. #44
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    well I suppose it is totally feasable to be in the headers rather than in the cats - since using dfe1s settings it doesnt appear to happen at all (perhaps once or twice) but at the same time its hard to tell if its kicking in! I think the ramp in ramp out rates have smoothed things a lot but the map pressure switch points I might play with - trying them back at stock settings but keeping the other settings dfe posted

  5. #45
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    Can someone look at my MAP settings for DFCO and let me know if it is optumized for a blower and 2bar MAP sensor. Please advise as I sm confused as to what the PSI is referenced to.

    Thanks



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  6. #46
    Lifetime Member limited cv8r's Avatar
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    Not sure what you are trying to achieve but the way you have b3308 to b3312 will not allow DFCO to activate.
    It's all good until it goes "Bang"

  7. #47
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    I am trying to get DFCO to work effectively on my vehicle. B3308 to B3312 is for an M6. Any help will be nice. Thanks!
    2002 GMC Sierra ECSB
    Turbonetics T7675 6lbs boost, 42lb injectors, Single 4 inch exhaust with Hi-Flow Cats, 6.0 swap, Comp Cam LS9 Cam, EFIlive Tune, E-fans, Snow Performance Meth Kit, soon to add KB Boost a Pump,

  8. #48
    New Member phils01z's Avatar
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    Quote Originally Posted by dfe1 View Post
    When DFCO comes in on pulse width typically drops to somewhere between .200 ms and .350 ms (depending on the vehicle) and O2 voltage goes to .004 mv. With the stock cals I've looked at, the transition to DFCO is very slow because of a slow rate of spark adjustment. DFCO won't become active until ignition timing hits the value in B3336. (The description is not correct. This isn't the value to which timing will be adjusted when DFCO is active-- it's the value that activates DFCO. Spark will drop until it reaches the value in B5915.

    Make sure that the value in B5919 isn't higher than the values in B3336 or you'll never hit the timing enabler for DFCO. Try values between .06 and .09 in B3334 to achieve a ramp in rate you're happy with. Values in B3335 (Ramp Out Rate) will be in the .4 to .7 range. Don't forget to adjust the other enablers (rpm, MAP, speed and throttle). If all else fails, send me your tun file.
    dfe1,

    I understand this is old, but if the descriptions of B3336 is incorrect, and we have data that proves that, why is it that the descriptions are never updated? I understand this is a daunting task to accomplish, but how does it ever get done? I am used to Ford tuning with BE and the biggest complaint I have about all of it, it is the lack of descriptions and clear documented logic diagrams of how calculations are actually made. I would think the entire community as a whole would benefit if there was a clear path. In the Ford market there is nothing. No clear route and if you want to search for it the task is nearly unachievable for a hobbyist.

    The GM platform from the birds eye view is much better documented and defined, but I always question if this description is incorrect, what else is incorrect. I suppose that is the cornerstone of the argument to go standalone. Everything is known.

    Philip
    2001 Corvette z06, OS 12593358, Calibration 12200411, def file version 7.94
    2005 Cadillac CTSV, OS 12592618, Calibration 12593480

  9. #49
    Forum tyhee Site Admin GMPX's Avatar
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    Quote Originally Posted by phils01z View Post
    dfe1,

    I understand this is old, but if the descriptions of B3336 is incorrect, and we have data that proves that, why is it that the descriptions are never updated? I understand this is a daunting task to accomplish, but how does it ever get done? I am used to Ford tuning with BE and the biggest complaint I have about all of it, it is the lack of descriptions and clear documented logic diagrams of how calculations are actually made. I would think the entire community as a whole would benefit if there was a clear path. In the Ford market there is nothing. No clear route and if you want to search for it the task is nearly unachievable for a hobbyist.

    The GM platform from the birds eye view is much better documented and defined, but I always question if this description is incorrect, what else is incorrect. I suppose that is the cornerstone of the argument to go standalone. Everything is known.

    Philip
    Philip, perhaps you have never taken a moment to think about how all aftermarket tuning packages for OEM ECM's are created. We aren't GM, or FORD, or Chrysler, we don't have access to the people that write the code for these computers, therefore there is a lot of assumptions made on how things work and sure there may be some parameters that don't behave as expected. But your options are really, live with these shortfalls and continue to use the OEM computer, install a Motec (or similar) where the company who designed then ECM openly provide info on how it works, take a .bin file from an OEM ECM and do a better job of figuring it out yourself.

    The descriptions are updated as required (usually by people explaining to us things don't work as described), however, we don't regenerate all the .calz files for each new software release just for description changes, so in the case of the LS1 unfortunately there has been no need to regenerate the .calz files for years.
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  10. #50
    New Member phils01z's Avatar
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    GMPX,
    I can clearly read you are the Admin of this site and I'm not sure if the goal is to look tough on this subject by attacking my lack of consideration. I started my paragraph by saying, "I understand this is a daunting task to accomplish, but how does it ever get done?". I would assume that would imply in just that instant alone I took the time to ponder how much work it would be. I thought about the scope of demanufacturing structured code written by someone else, who intends to not help you, and your only clues are likely the microcontroller processor calls themselves published by the processor manufacturer. You would look though seas of data looking for structured patterns based on the patterns in which they appear in other decompiled code. Then you would attempt to test that and see if you have hit paydirt. I also can appreciate considerable work goes into this to support the multitude of vehicles you offer BIN files to tune since you would have to do this process for each new processor you add to your list of supported models.

    I made all those realizations based on the fact I am a programmer myself. Endless hours a week all over the world building research equipment. While we do nothing similar I am pretty sure I have a far deeper appreciation that most could. I am in no way trying to devalue your efforts by saying if my code stops lives are at risk. Its allot of work with relentless testing. We all have had 4am nights trying to figure out why a bit flips state and it shouldn't causing some sort of havoc. All I wanted to know is if there is a log of known information. DFE1 could be totally wrong, but maybe he is totally right. Only way I can find out is if I test his opinion, but maybe someone already did. Maybe those efforts are someplace and I don't know.. On that note I think my question is valid. Its a mountain of work but who keeps track?

    Philip
    2001 Corvette z06, OS 12593358, Calibration 12200411, def file version 7.94
    2005 Cadillac CTSV, OS 12592618, Calibration 12593480

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