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Thread: understanding/tuning GM TBI : beginner

  1. #1
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    understanding/tuning GM TBI : beginner

    Greetings,

    I have owned TBI - powered rigs (91 Suburban, 94 G20 van) for a decade and while I have loved the dependability I have only rally partaken in basic troubleshooting and maintenance and I seek to know more and to better understand the system and, modify/tune it myself.

    The 215k mile 350 in my 94 G20 lost oil pressure and seized up. I will be installing either a used or rblt long block and am taking this opportunity to learn how to datalog and tune the system. I aim to mildly modify the engine with a Vortec 350 roller cam, perhapse a slight compresion bump along with simple TBI and exhaust mods to improve torque and pulling power. Nothing too crazy this time around.

    I have been looking at moates.net and a I like their AUD1 kit for OBD1 chip burning/tuning. I gather that Tuner Pro RT is a good software to use.

    My ECM service number is 16196395 and the 4 - letter code is BJLK

    I am still trying to understand ECM masks and BIN files and their relationship. Any help for this rookie is appreciated
    Last edited by Zodiac; 02-10-2015 at 05:49 PM.

  2. #2
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    Quote Originally Posted by Zodiac View Post
    Greetings,

    I have own TBI - powered rigs (91 Suburban, 94 G20 van) for a decade and while I have loved the dependability I have only rally partaken in basic troubleshooting and maintenance and I seek to know more and to better understand the system and, modify/tune it myself.

    The 215k mile 350 in my 94 G20 lost oil pressure and seized up. I will be installing either a used or rblt long block and am taking this opportunity to learn how to datalog and tune the system. I'd to mildly modify the engine with a Vortec 350 roller cam, perh apse a slight compresion bump along with simple TBI and exhaust mods to improve torque and pulling power. Nothing too crazy.

    I have been looking at moates.net and a I like their AUD1 kit for OBD1 chip burning/tuning. I gather that Tuner Pro RT is a good software to use.

    My ECM service number is 1616395 and the 4 - letter code is BJLK

    I am still trying to understand ECM masks and BIN files and the lir relationship. Any help for this rookie is appreciate.
    If memory serves me correctly that should be a $E6 mask although it could be a $OD.

  3. #3
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    What do the "$E6" and "$0D" stand for decoded?

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    Howdy, and welcome!

    The official name for those strange codes is Mask ID. The leading dollar sign means they are hexadecimal numbers and could actually be written as 230 ($E6) and 13 ($0D). Functionally they are a means to identify a specific program that runs in a vehicle computer. It's far easier (and more specific) to say "$0D" than "94 - 95 C/K Truck, Van, S-10 LN2 (16168505), 4.3L, 5.7L & 7.4L program." Many programs contain the code mask in the earliest part of the calibration data.

    Since a code mask identifies a program, a program with a specific mask may or not run on a given ecm/pcm. If the program is used in the same pcm as the factory intended, it will run. If the program is used in a different ecm, the code may not run. In a few cases users have determined that a program written for one ecm will run in another. In other cases it's been determined that one part number pcm replaces another. The two masks, $E6 and $0D, represent two different programs that GM may have used in your pcm.

    A bin file is a binary file. Data "read" from an ecm is in binary format. If this data is saved as it's read without being converted to a different data format, it's a binary file. Binary files which contain a copy of the ecm's operating program are usually saved with the extension .bin. Binary files that will work in your pcm will contain the $E6 or $0D program.

    After you have some experience you might shorthand some of these words and phrases to say things like "I'm using $E6 in a 7427 but I'd like to know where to get a $0D bin."

    Hope this helps.

  5. #5
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    Thank you for the welcome.

    Excellent reply. Very helpful indeed.

    I also found this thread that is very helpful.
    http://www.gearhead-efi.com/Fuel-Inj...must-read!-%29

  6. #6
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    I will be doing a lot more reading while I look for a suitable engine core.

    First things first. I will be getting a laptop and uploading Tuner Pro RT.

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    Welcome...lots of great info and guys here. I use the adu1 from moates as well. Always seems to work trouble free for me.

  8. #8
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    Quote Originally Posted by Zodiac View Post
    I will be doing a lot more reading while I look for a suitable engine core.

    First things first. I will be getting a laptop and uploading Tuner Pro RT.
    Personally I would start with a Vortec roller 350 core. Do you have emissions testing where you live in Texas? I also would not use the Vortec roller cam. Its actually a smaller cam than the stock TBI cam and does some goofy things to the spark advance requirements.

  9. #9
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    Quote Originally Posted by Fast355 View Post
    Personally I would start with a Vortec roller 350 core. Do you have emissions testing where you live in Texas? I also would not use the Vortec roller cam. Its actually a smaller cam than the stock TBI cam and does some goofy things to the spark advance requirements.
    Actually I have located a long block in a 96 G30 at a wrecking yard that has the 880 series 350 roller block, but with TBI 193 swirl port heads on it instead of the Vortec heads. 96 seems to have been an odd year in vans with the 350. Some export vans got a Vortec TBI 350.

    Anyhow, I have heard that EGR is a bit of a PITA to navigate when using the Vortec heads on TBI engines, though I do not require emissions testing where I am. The swirl port heads make decent torque and I'd like to keep it simple this go round so I will probably keep them. The 880 Block at the yard seems like a good candidate for a rebuild.

    What cam grind would you recommend for torque?
    Last edited by Zodiac; 02-16-2015 at 03:40 AM.

  10. #10
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    Quote Originally Posted by Zodiac View Post
    Actually I have located a long block in a 96 G30 at a wrecking yard that has the 880 series 350 roller block, but with TBI 193 swirl port heads on it instead of the Vortec heads. 96 seems to have been an odd year in vans with the 350. Some export vans got a Vortec TBI 350.

    Anyhow, I have heard that EGR is a bit of a PITA to navigate when using the Vortec heads on TBI engines, though I do not require emissions testing where I am. The swirl port heads make decent torque and I'd like to keep it simple this go round so I will probably keep them. The 880 Block at the yard seems like a good candidate for a rebuild.

    What cam grind would you recommend for torque?
    96 is when the newer Express/Savanna vans came out, but GM kept building the older G-vans over 8,600 gvw. Some of the 96 TBI G-vans had vortec heads on them.

    Keeping EGR really isn't that hard but a bit spendy. You would need the GMPP TBI Vortec intake and a driverside exhaust manifold with matching EGR pipe from a 96+ Vortec 350 P30 step van.

    As far as cam for low-end really depends on the skill of the tuner, your gear ratio, tire size and torque converter. I really prefer a straight or single pattern cam for the intake flow limited TBI heads. The TBI heads will never turn massive RPM or flow well much over .450. That being said they can work beautifully for low-midrange when cammed properly.

    I like a cam about 200-210* @ .050, .450/.450" lift on a 110* LSA ground advanced 4*. The 350 TBI from an engine standpoint would actually prefer a 108* or even 106* LSA but needs a bit higher stall converter and an experienced tuner to deal with the reduced idle vacuum that comes from a 108* lsa.
    Last edited by Fast355; 02-16-2015 at 06:21 AM.

  11. #11
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    Quote Originally Posted by Fast355 View Post
    96 is when the newer Express/Savanna vans came out, but GM kept building the older G-vans over 8,600 gvw. Some of the 96 TBI G-vans had vortec heads on them.

    Keeping EGR really isn't that hard but a bit spendy. You would need the GMPP TBI Vortec intake and a driverside exhaust manifold with matching EGR pipe from a 96+ Vortec 350 P30 step van.

    As far as cam for low-end really depends on the skill of the tuner, your gear ratio, tire size and torque converter. I really prefer a straight or single pattern cam for the intake flow limited TBI heads. The TBI heads will never turn massive RPM or flow well much over .450. That being said they can work beautifully for low-midrange when cammed properly.

    I like a cam about 200-210* @ .050, .450/.450" lift on a 110* LSA ground advanced 4*. The 350 TBI from an engine standpoint would actually prefer a 108* or even 106* LSA but needs a bit higher stall converter and an experienced tuner to deal with the reduced idle vacuum that comes from a 108* lsa.
    Well, in my search for a core I found (3) good "638" 350 longblocks to choose from.......and I stumbled upon a '96 GMC 3500 van at a wrecking yard that has a TBI454/4L80e combo in it and a 14BFF rear axle under it. The harness and 7427 computer are there and the engine is only missing a few replaceable parts. The odometer only reads 76k miles. Needless to say, I will be stripping that van clean of its drivetrain and relevant parts.

    I will still be putting a 350 back into this van for the time being, but it may be the recipient of the 454/4L80e combo in the near future. This van will also be converted to 4wd in the coming year.

    Anyhow, once I secure all of these drivetrain components, I will be ordering the AUD1 from Moates.net and get started.

    A friend of mine recommended the book "How to tune and modify Chevrolet Fuel Injectjon" and I will be reading that as part of my intro education to tuning.

  12. #12
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    96 is when the newer Express/Savanna vans came out, but GM kept building the older G-vans over 8,600 gvw. Some of the 96 TBI G-vans had vortec heads on them.
    The easiest way to find the 96 TBI G chassis is to look at cutaway chassis vehicles. Small school buses and box trucks are made on this chassis. People have said for years that some of the G chassis vehicles were sold in the US with the Vortec heads and TBI but I have yet to see one. I'm thinking they're pretty uncommon. I have seen a Vortec head TBI P chassis step van though at the junkyard. I don't know if that chassis was exported out of the US for the body builder then brought back or if there was another reason why it was so equipped, but the manifold was definitely not an aftermarket part. I have searched and searched through the calibration lists for cals for a Vortec head TBI vehicle and so far all have been export models. I did post a calibration for a factory TBI / Vortec engine.

    I am extremely happy with the HT383 cam I installed in one of our small bus engines last year. Although that engine is Vortec/PFI, I'd expect similar results in a TBI engine.

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