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Thread: Modified 454 TBI Tuning Advice Needed

  1. #1
    Carb and Points!
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    Modified 454 TBI Tuning Advice Needed

    I am looking for some guidance on tuning a chip for a modified 1989 C3500 with 454 TBI, TH400. For some background, I bought the truck in March and had a lot of work done including heads, cam and intake upgrades,
    replaced the old distributor and ECM unit with a new and remanufactured one respectively and all new plumbing from the radiator to the oil cooler to the AC unit to the master cylinder, new motor mounts and brake calipers ... most of the go and stop parts of this truck have been replaced/rebuilt. Now, after all of this it can run pretty good at times, and others not so much. The current chip is an old Jet 6 pack that came with it. I have serious questions about what modes it is actually running in since I can start it in security mode which I don't think is supposed to be allowed and I can rev over the 2000 RPM limit in valet mode. There seems to be no difference when changing between the modes whatsoever, it seems I get either one of two modes... one which runs with a nice smooth idle with good acceleration (stage 1 or 2 maybe?) or one that is a little shaky on idle and has an anemic response to the gas pedal (economy mode?). When I go for a drive I never know which one I am going to get. Another issue is the truck cannot hold idle, it needs just the slightest touch on the gas pedal to start and to keep it from stalling out when stopping. Otherwise, I can make it hold 'idle' as low as around 400 rpm as long as I keep that slight touch on the pedal.


    What I am looking for is a good starting bin file and some advice on where to go from there. I burned a bin for a 1990 454 SS I found on this site and slapped it in there, that did not go well. Very rough and jittery and backfired when I stepped on the gas. Something like whichever Jet mode seems to be working would be nice to start with (I imagine this is probably the stage 1 or 2 setting), unfortunately I don't know how exactly to read that off of there.

    For reference my modifications include

    Edelbrock 60499 Heads (raises compression to 8.8:1)
    Edelbrock 3764 TBI Intake Manifold
    Lunati Voodoo Cam/lifters/aluminum rockers 10110701 (213/219 Duration @0.50, .515/.530 lift)
    Higher flow 96+ Vortec fuel pump
    Cat delete, Gibson swept side exhaust


    Any advice is appreciated.


    -Austen
    Last edited by austenz28; 08-23-2018 at 10:28 PM.

  2. #2
    Carb and Points!
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    So just kidding on that 1990 454 SS bin, went to go put the Jet chip back in and noticed I had put it in backwards... it actually works now, holds idle at 1000 which means no more clutch foot braking for this guy! New problem is this one only has tables filled up to 3600 RPM, anyone have a version of this that goes up past 5000? The file I am using is ANZM_90_C-1500_7_4TBI_3_speed_auto.bin

  3. #3
    Super Moderator dave w's Avatar
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    There is the option upgrading the computer to get 6000 RPM's spark tables and and an open throttle fuel table to 6400 RPM's: http://www.gearhead-efi.com/Fuel-Inj...out-Directions!

    The upgrade computer can operate a 4L80E.
    http://www.gearhead-efi.com/Fuel-Inj...Information-31
    http://www.gearhead-efi.com/Fuel-Inj...Information-OE

    dave w

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