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Thread: TBI Tuning for dummies?

  1. #1
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    TBI Tuning for dummies?

    Hi all, I'm totally new to the TBI tuning (or tuning in general) and I'm just trying to figure out the basics. I've been reading a lot of different threads and post but they all seem to assume that you already have an understanding on why you do certain things. So, I'm wondering if anybody has any links to information on why we tune certain things and what are the items you want to start with. I'm not trying to be a pro or tune a race car. I just want to have enough of an understanding on how to adjust my tune and optimize it for some changes such as a new cam, exhaust, TBI mods etc. as I make those changes.

    Here is where I am now. I've got the Moates Burn 2 and G1 adapter. I've figured out how to read the bin off my stock chip, how to load that into Tuner Pro along with all the definitions etc. and how to then burn the bin back to a new chip.

    So, my question now is where should I start and what things should I look at? I'm not necessarily looking for how to do things. I'm pretty sure can find that on the interwebs once I know what I'm looking for. I'm mostly looking for the what and why.

    I see a lot about VE tuning. Is that where I should start? I've read that spark advance is one of the later things you should work on. Also, why is VE tuning so important if the PCM already adjusts fueling based on O2 sensor readings?

    What would be the next things to look at after VE?

    Thanks for any help.

  2. #2
    Super Moderator dave w's Avatar
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    Perhaps a brief description of what your tuning will help. Year / Make / Model / Engine / Transmission / ECM or PCM information.

    That helps with knowing what TunerPro files are to be used. Then the uphill fun begins.

    dave w

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    Quote Originally Posted by IamBrad View Post
    I see a lot about VE tuning. Is that where I should start? I've read that spark advance is one of the later things you should work on. Also, why is VE tuning so important if the PCM already adjusts fueling based on O2 sensor readings?

    What would be the next things to look at after VE?

    Thanks for any help.
    Since you alluded that you don't need a tutorial...you need to adjust your VE tables so your datalogs return BLMs of 128+- 3. There's going to be "events" in the PCM i.e. power enrichment (PE) where the PCM locks the BLMs at 128 then provides additional fueling/timing etc so having your VEs adjusted to return a BLM of 128 is desirable.

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    Quote Originally Posted by dave w View Post
    Perhaps a brief description of what your tuning will help. Year / Make / Model / Engine / Transmission / ECM or PCM information.

    That helps with knowing what TunerPro files are to be used. Then the uphill fun begins.

    dave w
    It's a 1994 C1500 with a 305 and 4L60e. the PCM is 16196395 and the bin is BHMD. The engine is stock. I did add some shorty headers, high flow cat and did the Ultimate TBI mod. I did add a TBI spacer but that was more to be able to clear the distributor after removing the collar that the TBI units have.

    Future upgrades will be a mild roller cam .447/.459 lift with 201/208 duration. I have some 081 heads also with larger intake values but I'm not sure I'm going to use them yet. Because I'm more interested in low end torque than high end HP.

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    Quote Originally Posted by stew86MCSS396 View Post
    Since you alluded that you don't need a tutorial...you need to adjust your VE tables so your datalogs return BLMs of 128+- 3. There's going to be "events" in the PCM i.e. power enrichment (PE) where the PCM locks the BLMs at 128 then provides additional fueling/timing etc so having your VEs adjusted to return a BLM of 128 is desirable.
    Right there are already good tutorials out there like the one from EagleMark. But what I'm trying to figure out is why are we doing this. What does adjusting your VE do to the engine.

    Does it create more power or just make it run smoother?
    What is the goal of the VE adjustment? Does it make it easier for the PCM to adjust for stoic mixture if your VE is adjusted correctly or is there another reason to do it?
    Should VE be adjusted before other factors?
    How does PE Factor into this?
    At what point do you try and adjust PE.
    Are there other things to l should look at before this.

    Of course to make it harder I'm trying to find something in normal English and not super technical jargon.

  6. #6
    Super Moderator dave w's Avatar
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    Quote Originally Posted by IamBrad View Post
    It's a 1994 C1500 with a 305 and 4L60e. the PCM is 16196395 and the bin is BHMD. The engine is stock. I did add some shorty headers, high flow cat and did the Ultimate TBI mod. I did add a TBI spacer but that was more to be able to clear the distributor after removing the collar that the TBI units have.

    Future upgrades will be a mild roller cam .447/.459 lift with 201/208 duration. I have some 081 heads also with larger intake values but I'm not sure I'm going to use them yet. Because I'm more interested in low end torque than high end HP.
    I'm slightly confused, 16196395 is usually $OE definition for a 4L80E : http://www.gearhead-efi.com/Fuel-Inj...Information-OE

    What I was able to find is BHMD is listed for $OD 16197427 : http://www.gearhead-efi.com/Fuel-Inj...Information-0D

    There is information showing the 16196395 will work with $OD BHMD, but I don't have personal experience to verify 16196395 will work with $OD BHMD. Perhaps using 16197427 would be an option?

    The overriding factor is BHMD is $OD, so tuning with $OD is the path forward.
    TunerPro RT File Type: adx A217 $0D TP5 v250.adx
    TunerPro RT File Type: xdf Advanced $0D TP5 v251.xdf

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    Quote Originally Posted by dave w View Post
    I'm slightly confused, 16196395 is usually $OE definition for a 4L80E : http://www.gearhead-efi.com/Fuel-Inj...Information-OE

    What I was able to find is BHMD is listed for $OD 16197427 : http://www.gearhead-efi.com/Fuel-Inj...Information-0D

    There is information showing the 16196395 will work with $OD BHMD, but I don't have personal experience to verify 16196395 will work with $OD BHMD. Perhaps using 16197427 would be an option?
    Haha you and me both. It took me about a day to figure that out. Everything was telling me it should be $0E and that it was only used in HD trucks with the 4L80E. But I guess GM didn't pay attention to that. Anyway the $0D stuff seems to work well.
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    Super Moderator dave w's Avatar
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    Next step is to post a data log. Advanced tuners often use Air Fuel Ratios to tune with: http://www.gearhead-efi.com/Fuel-Inj...ng-Spreadsheet

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    8625, 7427 and 6395 are mostly interchangeable and all can run $0E, $0D, and $31 code. $0D is for a 4L60E, $0E and $31 are for the 4L80E. I would start with the latest 1995 code for your truck combination as a base for your tune and work from there. Do you have a wideband? It's possible to tap its 0-5 volt output to the EGR position sensor wiring and hack it into the datastream in place of battery voltage. Then you can feed the datalog into a spreadsheet to help you tune the VE table. That's more accurate than BLM tuning.
    1995 K1500, Cadillac 500 TBI with 4L80E swap. 7427 PCM and 454 TBI.

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    Quote Originally Posted by mihela View Post
    8625, 7427 and 6395 are mostly interchangeable and all can run $0E, $0D, and $31 code. $0D is for a 4L60E, $0E and $31 are for the 4L80E. I would start with the latest 1995 code for your truck combination as a base for your tune and work from there. Do you have a wideband? It's possible to tap its 0-5 volt output to the EGR position sensor wiring and hack it into the datastream in place of battery voltage. Then you can feed the datalog into a spreadsheet to help you tune the VE table. That's more accurate than BLM tuning.
    If your transmission is a '94 DON'T use a '95 file, the transmission changed in '95.
    -Carl

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    Where can I find what transmission are interchangeable?

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    Hiya, for the TBI trucks the '93/'94 4L60E trans can interchange. From memory, the '95 up went to PWM TCC controls. I believe this can be changed in the .bin file. It's been a long time since I looked at all that stuff. Hopefully someone can chime in with better memory than me :)
    -Carl

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    Thanks, trying to find a replacement for a 98 1500 for a friend.

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    For the 4L60E, yes. good point. I'd break one of those like a twig.
    1995 K1500, Cadillac 500 TBI with 4L80E swap. 7427 PCM and 454 TBI.

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    Quote Originally Posted by ras"86 View Post
    Where can I find what transmission are interchangeable?
    There was a good video on YouTube I found a while back. Don't hold me to it but from what I remember the model years that are the same are 93-94, 95 (single year only), 96-99. After that I stopped paying attention.

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