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Thread: Minimum Injector Pulse Width

  1. #1
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    Default Minimum Injector Pulse Width

    B4003, can a change in the pulse width effect the AFR throughout the power band or only other then when in Power Enrichment mode or when in Decel fuel cutoff.

    Thanks, Curt
    99C5, mn6, Vortec T trim, Snow meth injection, AFR 205s, ARP studs,Comp 224*112*+2*.580", YellaTerra RRs, PRC Ti's w/dbls, Supermaxx LTs, No Cats, Corsa Indys, LS6Intk, Hurst, Fikse Aro18"s. Pilot Sports 315/30,265/35, 04ZO6 Shocks Hotchkis bars, EBC YellowStuff pads, SS hoses, LM-1, EFILive, 2002 OS. RPS dual disc Clutch, DTE Strut Brace & output shaft.

  2. #2
    EFILive Crew Site Admin Tordne's Avatar
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    I'll be real interested in this as well. Well, I'm interested in anything to do with injectors really

    You just inspired me to make a map of that B4003 table and look at data from a couple of runs.
    Andrew
    EFILive Crew


  3. #3
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    A friend, an experienced tuner, with an identical set of modifications, 2001 C5, reduced the pulse width 10% and his fuel mileage on a long Interstate trip went from 28 to 32. He uses HP Tuners with a wide band. Someone on the HP forum told him, in a PM, about this. Since the cam, mine has dropped to 28. My LTFT are -1 to 0. My cruise AFRs are in the high 14's.
    99C5, mn6, Vortec T trim, Snow meth injection, AFR 205s, ARP studs,Comp 224*112*+2*.580", YellaTerra RRs, PRC Ti's w/dbls, Supermaxx LTs, No Cats, Corsa Indys, LS6Intk, Hurst, Fikse Aro18"s. Pilot Sports 315/30,265/35, 04ZO6 Shocks Hotchkis bars, EBC YellowStuff pads, SS hoses, LM-1, EFILive, 2002 OS. RPS dual disc Clutch, DTE Strut Brace & output shaft.

  4. #4
    EFILive Crew Site Admin Tordne's Avatar
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    Interesting. I wonder if you reduced the B4003 table would you also reduce the B4004 table?

    The B3701 table (Offset) also gets added for the battery voltage to determine the final commanded pulse width. I changed the offset table and that made a massive difference to my VE table.

    I am kind of thinking of a reason why you wouldn't just drop the B4003 & B004 tables down to say 0.50. You are never going to be commanding that low except when DFCO kicks in. And that way you wouldn't be commanding a bigger pulse width than you perhaps need.

    Does that sound reasonable?

    Cheers,
    Andrew
    EFILive Crew


  5. #5
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    Anyone?????
    99C5, mn6, Vortec T trim, Snow meth injection, AFR 205s, ARP studs,Comp 224*112*+2*.580", YellaTerra RRs, PRC Ti's w/dbls, Supermaxx LTs, No Cats, Corsa Indys, LS6Intk, Hurst, Fikse Aro18"s. Pilot Sports 315/30,265/35, 04ZO6 Shocks Hotchkis bars, EBC YellowStuff pads, SS hoses, LM-1, EFILive, 2002 OS. RPS dual disc Clutch, DTE Strut Brace & output shaft.

  6. #6
    EFILive Distributor dfe1's Avatar
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    Hard to say. When my truck goes to DFCO, reported pulse width is .244 milliseconds. Smallest value in B4003 and B4004 is .759975 ms. The numbers on my C5 are similar.
    DigitalEFI- EFILive US Distributor
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  7. #7
    Lifetime Member jfpilla's Avatar
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    The minimum logged for mine is .671. B4003-4 are 1.26. Not much help.
    2003 red vert
    Mods:
    LS7 crate engine, wet sump, 24xx reluctor
    LPE 100mm MAF
    Vararam, cold air intake and bridge
    RPM Level 6/4L60e trans
    3.42 gears
    Yank SS3600
    1-7/8" AR headers
    Z06 exhaust
    470rwhp 437rwtq
    1/8th mi-1.526-60'-6.862-1/8th-@100.74mph

  8. #8
    EFILive Crew Site Admin Tordne's Avatar
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    Those minimum pulse widths are more than likely when DFCO becomes active and commands a pulse width of 0, which will then refer to the B4005 table and then add that pulse width.

    I have experimented over the last couple of days with lowering both the B4003 & B4004 tables (down to 0.85) and at the same time 0'ing the B4005 table > 1ms.

    Today I returned it all back to previous settings as I did not see any real difference.
    Andrew
    EFILive Crew


  9. #9
    EFILive Distributor dfe1's Avatar
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    As if we weren't already confused enough, these are my results. I changed B4003 Min Pulse Width and B4004 Default Min Pulse Width as follows-
    B4003 from .759875 to .683888
    B4004 from .866258 to .653493
    And also changed B4006 Small Pulse Width threshhold from 3.99 to 3.49.

    Pulse width in DFCO changed from .244 ms to .214 ms.

    I haven't driven it enough to determine if anything else has changed, but it doesn't appear that it has. Now I have to go back and change each one back to the original value to see what caused the change.
    DigitalEFI- EFILive US Distributor
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  10. #10
    EFILive Crew Site Admin Tordne's Avatar
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    There is also the Voltage Offset table. Could that explain anything with the variance?
    Andrew
    EFILive Crew


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