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Thread: mm3 Variation

  1. #1
    Lifetime Member FUBAR's Avatar
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    Default mm3 Variation

    All right, I've been seeing some interesting information regarding mm3's that I would like some input on.

    Data logging my EFI tunes, I keep seeing mm3 spike to a high number, and slowly or quickly taper off. How much? Varies by truck. Mine, usually 147mm3 @ a 2600uS @ 2800RPM down to 120mm3 @ 2800uS, 3600RPM. Never understood how mm3's could taper off if fuel pressure and uS are increasing. I understand mm3 is purely a reference of pressure and injector opening time, etc. So why do they taper off?

    Now, here's a comparable that's interesting. Using my box tuner as a base file, torque limiter off, I ran my script over top of it, verify everything changed, here are the results: 162mm3 @ 2600uS @ 2800RPM UP to 183mm3 @ 2800uS @ 3600RPM. The truck felt much more powerful than my clean EFI tune(when I say "clean" I mean a box tune hasn't touched it.) Throttle response is more instantaneous, and the truck just feels like a frieght train also.

    So, here's what I did, set my whole Pedal mm3 table 25% - 100% 30mm3 on each tune (clean EFI and box tune base file.) Here's what happened, clean EFI tune did limit me to 30mm3, Box tune base file with same script and settings as clean EFI tune limited to 98mm3 fueling 63mm3 more than I commanded. Multiplier? I don't know. But here's what I did to tame down the Box tune base file: I went from 25%TP @5mm3 and worked it up to a max of 120mm3 @ 100%TP. Throttle resonse still was instantaneous, but overall power was cut back.

    I've heard around 145mm3 is considered WOT because of the mathmatics, but I don't believe so after about grenading my tranny and lookign in the logs.
    Food for thought...I'd like to know what you guys think. Attached are 2 screen shots of the Clean EFI tune with my script written over it, and the other the Box tune as the base file with my script written over top of it.

    -Andrew

    Click image for larger version. 

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    Last edited by FUBAR; September 15th, 2011 at 08:51 AM. Reason: uploaded wrong pic
    06 5.9L, EFILive / Silver Bullet Tuning
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  2. #2
    Junior Member CIDRAUGHN's Avatar
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    Ive been wondering about this one as well. Ive seen mm3 go up to 170 or so, sometimes a bit higher, but then it falls back off.
    06 Dodge RCLB 2500 5.9L Hamilton, Maxxspool, Wicked Diesels, Bullseye Power, Industrial Injection, South Bend Clutch, Amsoil, K&N, ARP,EFILive, T&C Diesel, ATS, GDP...

  3. #3
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    im having the exact same issue on one truck I'm tuning. I'm also doing a manual trans truck right now that's holds 145mm3 perfectly through the whole run. I'm hoping the new tables released tonight help this. I'll now tomorrow I guess

  4. #4
    Lifetime Member GMPX's Avatar
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    The ECM is using the mm3 as the means of controlling a lot of things, this was one of the area's we battled with when it came to limiters. Mysterious mm3 values being commanded. I did a special OS mod so we could log a lot of the mm3 values the ECM uses and this helped nail down the limiters. I don't think there is a multiplier as such, it will be another part of the code overriding the throttle table values. In your logs, do you have the PID 'CM.INJSTAT' "Injector Fueling Status"? If yes, you will probably see that change number as these unexpected mm3 values come and go.
    If you have it, what number is that PID showing when the mm3 seems to have a mind of it's own? I can tell you, when it's at 12 it's trying to limit RPM.
    I no longer monitor the forum, please either post your question or create a support ticket.

  5. #5
    Lifetime Member FUBAR's Avatar
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    Ross, nowhere in my log does "CM.INJSTAT" deviate from the value "0" It's always "0"
    06 5.9L, EFILive / Silver Bullet Tuning
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  6. #6
    Lifetime Member 2007 5.9's Avatar
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    I'll be performing the same test today with my box tune to verify the phenomenon.

    Ross, I'll send you my files and log for you to look at if my truck does as Andrews does.

    ~Les
    Les Szmidt
    2007 5.9 Dodge Ram
    2014 Ram 3500 Aisin tuning Emissions Equipped
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  7. #7
    Lifetime Member Dmaxink's Avatar
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    Testing this as we speak also...
    -Kory

    I'm out of ideas? Nah trick... When in doubt, 0xFFFF it out!

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  8. #8
    Lifetime Member 2007 5.9's Avatar
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    So in some initial testing....my truck acts VERY different when running my DD tune scripted over my box tune.

    Throttle sensitivity is increased substantially.

    I'm going to try to log a run, but I'm nursing a patched boost boot until my new one arrives, so no wot runs.

    ~Les
    Les Szmidt
    2007 5.9 Dodge Ram
    2014 Ram 3500 Aisin tuning Emissions Equipped
    EFI Live Cummins BETA Tester
    Silver Bullet Tuning
    silverbullettuning@gmail.com
    www.youtube.com/ljszmidt
    http://www.facebook.com/SilverBulletTuninig

  9. #9
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    I myself am seeing this , I tested with the same scenario as Andrew (Fubar). And according to my logs and the butt meter i get much more on he bottom to mid range! Definitey needs investigating. I will post logs in the next lil bit.
    06 2500 SLT 4x4 , G56, 105,000 miles, 2nd exhaust manifold, 2nd gen air intake horn, SBC 3600 DD, I. I. 90HP Sticks, straight pipe, manual high idle mod, custom air intake , and pretty much everything else engine wise is stock... LEARNING EFI LIVE

  10. #10
    Lifetime Member AdamRRT's Avatar
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    Is it possible when the PID you're reading when mm3 is falling off inversely to pressure and duration increases, that the PID is actually reading mm3 as it correlates to RPM? And therefore you're eating more fuel per cylinder, just a little faster than your CP3 (or injector or whatever fuel system part is being read) can keep up? The thought in my head thinks back to how a certain amount of nitrous feels better at low RPM than at high RPM because you're burning it across more RPM. More torque when I spray at 3k rpm compared to 5500 rpm. Does that make any sense? Just a thought about why we could be seeing funny values. That's all. Had a few hours of drive time to ponder such issues. I'll try to meet with Phil (Bluecat) tomorrow and see what he comes up with, and update the discussion. I'm just really excited to see some progress. Seems a little stagnant this past little bit.
    EFI Live, Maxxed Out auto trans, Edge TC, FASS, 35's, 4" lift, E.D. 62/68/12, 70 hp tips.

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