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Thread: fuel curves for 7747 running stock vortec shortblock

  1. #1
    Electronic Ignition!
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    fuel curves for 7747 running stock vortec shortblock

    ok so over at tg.org ive been trying to dig up how to modify fuel tables for vortec heads, given that my A/F gear is hard wired into the fiesta right now.

    my buddy figured the stock chip would work, but it ran bad. even with extra FP. Now were back at stock, and im trying to blindly burn him a winner. so far a compromise between fcar and big car LT1 timing curves is where were at there, but fueling is def. off.

    can i just reference a stock truck fuel table or are the newer ecus way different?

  2. #2
    EFI GearHead ! EagleMark's Avatar
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    That's not much to go on, would be nice to know the entire setup, engine and mods, trans and vehicle. Even then there is no answer to exact fuel table on a modified engine.

    Timing will be off again once you get fuel close... have to get fuel close first then timing. But it runs so your doing better than a lot of guys.

    Most newer ECU are MAF... 7747 is SD Speed Density.

    Even if we knew exactly what you were working on the answer would probably be the same. Record data, adjust VE record data adjust VE once your close to 128 all the time then work on timing. Dave W has shared a performance small block chevy timing curve he worked hard on, I would use that and work on fuel. Always watch your knock sensor.

    Seems you have a wideband you have tuned off of? This is tuning by recording data from ALDL port with cable to laptop. Around here we mostly use TunerPro.

    Get your cable hooked up to laptop with TunerPro or whatever you use, get the right files they are all here:
    http://www.gearhead-efi.com/Fuel-Inj...d-tuning-files

    Yours is (1227747 is $42):
    http://www.gearhead-efi.com/Fuel-Inj...Information-42

    Record data and adjust VE. There are also some excellent speadsheets Dave has made to do the calculations for you. Enter your VE from chip your starting with, enter recoded BLMs and then insert new VE table.

    Hope that gets you going in the right direction!

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
    -= =-

  3. #3
    Super Moderator Six_Shooter's Avatar
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    Before you go any farther, I have to ask:

    Are you using the Vortec spark plugs?
    The man who says something is impossible, is usually interrupted by the man doing it.

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    its got zero mods, stock cam and ex manifolds. Id tune it but i have my equipment tied up in the fiesta project and dont really wanna uninstall it. the wideband i got is kinda a pain to adapt to a new vehicle, I think it was intended for permanent installation.

  5. #5
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    the lt1 tables are what most people are using at tg.org, with most saying power is good with the f body ones so thats what we started with and its too aggressive, and we just burned 7747 limp mode fueling into the chip o got from a friend so it'd have a runnable a/f ratio, but its crappy. obviously not right for the air demands of the heads.

  6. #6
    EFI GearHead ! EagleMark's Avatar
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    Quote Originally Posted by Six_Shooter View Post
    Before you go any farther, I have to ask:

    Are you using the Vortec spark plugs?
    He obviously knows something! Are you?

    I'll attach a good 7747 bin to start with, it is one Dave has tuned and shared with us.

    You can tune with your laptop and a cable, no need to uninstall and reinstall a wideband.
    Attached Files Attached Files

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
    -= =-

  7. #7
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    yeah i can burn and test, thats what we were gonna do. Thats AMUR tuned for what setup though? Im not sure what good I will be able to gleam from that without knowing much else about the setup it is tuned for, as he doesnt have a new cam or high lift rockers or anything. It was just a good running 60K vortec 350 motor from a totaled city rig, nothing special.

    i thought that was a joke...

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    Spark tables can be taken from iron head, B body LT1 or from OBDII Vortec engine. Reportedly there were van engines with L31 Vortec engine and TBI intake. Edelbrock Vortec TBI intake was originally designed for these engines!! Look for that cal and maybe you've got something. These cals might be from a Vortec head engine with VE tables for a mild cam to get ya started.
    Attached Files Attached Files

  9. #9
    Electronic Ignition!
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    hmmm i dont know any obd2 resources, care to point me to any that are worthwhile? google is so hit and miss I'll be looking but finding a calibration list for my crown vic took days. WHY are there so many ford ecus and cals btw?? FML! doing basic tuning on my crown vic took 6 months of searching just to wind up with a tunable ecu that runs my motor but wont run my tranny.

    LOL!

  10. #10
    Super Moderator Six_Shooter's Avatar
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    Quote Originally Posted by ODDDOYLERULES View Post
    i thought that was a joke...
    Not a joke, serious question.

    The Vortec and earlier SBC spark plugs are different.

    I faught with a Vortec swap in my Grandfather's '71 Chev Pick up, because he installed older style short reach spark plugs. We were informed of the difference last year, and the difference was night and day.
    The man who says something is impossible, is usually interrupted by the man doing it.

  11. #11
    Super Moderator dave w's Avatar
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    Everyone tunes differently. I tune the '7747 with VE1 and VE2 added, then VE2 zero. I live on the West Coast, so by law, all grades of pump fuel is required to have 10% ethanol. My fuel and spark tables are adjusted according the pump fuel available.

    The attached '7747 .bin has many modifications, including PE and AE. It's from an actual running / driving 350 Vortec in a Jeep YJ. I'm sure the fuel and timing are not going to be exact for a heavier Full Size GM Pickup / Suburban, but would very likely be close.

    I 100% agree with Six_Shooter about checking the spark plugs in the Vortec engine. I helped a F-Body owner who did a Vortec 350 swap, and installed the wrong spark plugs because he told the parts counter person the Make / Model / Year of the F-Body he wanted spark plugs for.

    dave w
    Attached Files Attached Files

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    The TBI van probably wasn't OBDII. If you look around the pacific performance forum you can find cals and possibly screenshots of various tables needed for your tune. The cals I posted were for a GM 300hp crate motor in a 90 1/2 ton 4X4 truck with 4L60E trans. The truck used a 454 TB and edelbrock TBI intake (waste of $$) so you'll want to adjust the injector constant appropriately.

  13. #13
    EFI GearHead ! EagleMark's Avatar
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    Quote Originally Posted by Six_Shooter View Post
    Not a joke, serious question.

    The Vortec and earlier SBC spark plugs are different.

    I faught with a Vortec swap in my Grandfather's '71 Chev Pick up, because he installed older style short reach spark plugs. We were informed of the difference last year, and the difference was night and day.
    Man I had the same thing in a 440 Mopar!!! Guy had Accell short spark plugs for headers! Outside is supposed to be short for headers. They were also short on the inside!!! Spark plug was half way in the threads!!! Never made it to cobustion chamber. Went to get new plugs and they were twice as long? Guy looked up the Accell and came out with one, we compared, half as long... Accell books still list it as correct plug for a 440 Mopar.

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
    -= =-

  14. #14
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    Internet says cal for van with Vortec TBI is BRDW. It's OBD1 and $63 mask. This post on FSC has some info you might want:
    http://www.fullsizechevy.com/forum/a.../t-363135.html

    If you find a copy of that cal (might be on this site) please link here so I can find it later.
    Thanks.

  15. #15
    EFI GearHead ! EagleMark's Avatar
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    I couldn't find that bin... man that's an oddball... $63 is not supported on TunerPro or TunerCat and probably never would be as it's listed as a 16197427=96-97 export truck vortec head tbi\63\Brdw.bin So that should be OBDII but it's only export and has OBDI PCM... and most exports I have seen do not use closed loop.

    Found one guy in Dubai had a 1995 Imaplala SS, came with no cats, still came with O2 sensors although they were all turned off in bin... to run open loop. Weird how they took out cats but left in O2 sensors even though PCM ran open loop. Fuel still has lead in it in Dubai.

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
    -= =-

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