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Thread: 7427 Rev limiter / 4L80E question

  1. #1
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    Lightbulb 7427 Rev limiter / 4L80E question

    Hey guys.. I have a few questions for you all regarding a 7427 swap w/a 4L80E. It is my understanding that I need to use $0E for the 4L80E. After that is where I get a bit foggy. So here is the back story 1st. I have a 92 454ss w/4L80E and 7060 PCM. The engine was formerly boosted and I had the EBL + 7060 piggy backed. Worked good for what it was. Since then I have swapped in a 540 BBC and gone carb/HEI distro and kept the 7060 for controlling the 4L80E.

    Believe it or not I still have the EBL piggy backed with the 7060. The only thing the EBL brings to the table at the moment is WBO2 logging as unfortunately the EBL won't control a 4L60E or 4L80E. So, ideally I would like to ditch the EBL and have WBO2 logging via the 7060, but I read that isn't possible (or no one has figured it out yet). It is a major PITA to log trans functions w/the 7060 and WBO2 via EBL. I would like to aggregate the data streams which is where the 7427 comes in. I already found (on here) how to input a WBO2 in the 7427 so that is a good start. :-)


    Here's a few questions I have regarding the 7427:


    1) In my case, is it necessary to have a MEMCAL from a v8? My plan is to use an BURN2 (or Ostrich) along with the GP1. I picked up a 7427 w/the BJXK BCC. Hopefully I can use it...?

    2) Regarding shift points / rev limiters for the 4L80E - what tables are these in the 7427? I found "Upshift RPM vs Shift" but it's zero'd out in the 0E bins (BHDF, BJDR, BMHK)??? I know in the 7060, to up the rev limiter it's in: "Kickdown up/down vs MPH" but I could not find the equivalent in the 7427.

    3) Regarding the other 4L80E tables, like the TCC and line pressure, etc.. Are the bins floating around out there they have been "optimized"? I'm assuming BHDF, BJDR and BMHK are stock bins. Or am I on my own here trying to firm up the shifts and adjust TCC Lockup?

    4) Is there a way to input a "Performance Mode" switch in the 7427? IIRC some of the older ECU's had this functionality where you could push a button and it would use a 2nd set of shift tables.

  2. #2
    Fuel Injected! gregs78cam's Avatar
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    Yes getting the '7427 to datalog WBO2, and run your 4L80E is relatively easy. To answer your questions:

    1. You should have no problem using that '7427 to run the 4L80E. Just make sure it has a memcal with a chip with a $0E .bin burned onto it. I don't know if a V8 memcal is mandatory, as there are no fuel or timing outputs being used. But you should probably spend some time disabling any DTC's that you don't need. For datalogging and .bin editing be sure so use a $0E .xdf.

    2. Doing the above should provide you with all the parameters you need to tweak the 4L80E to your liking. Most all of the trans stuff is near the bottom of the Constants, and Tables sections. Attached is the .xdf that 93V8S10 made long ago, and I added few features to, I use it for both of my TBI vehicles.

    3. Anything out there that is "optimized", wont be optimized for your engine, gear ratio, or vehicle.

    4. I don't believe that feature exists for the '7427.
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    Fuel Injected! JeepsAndGuns's Avatar
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    To run a V8 engine I would reccomend a V8 memcal. There are differences in the limp home chips and the knock filter.
    I just sold a V8 memcal to another member who was having issues with his system. He had a V6 memcal and a V8 engine.
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    Quote Originally Posted by gregs78cam View Post
    4. I don't believe that feature exists for the '7427.
    i seem to remember seeing both code references and maybe even a diagram or two of a "manual, normal, perfomance" shift pattern switch.... i'll have to look around to be sure.
    1995 Chevrolet Monte Carlo LS 3100 + 4T60E


  5. #5
    billygraves
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    Last edited by billygraves; 06-30-2019 at 06:27 PM.

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    Quote Originally Posted by billygraves View Post
    The rule with the 4L80-E is to keep the Force Motor, Valvebody, space plate, and TCM/PCM as a UNIT. If you want to know why I can respond.
    Billy, that reminds of me of a question that i really don't know who else to ask and get a solid answer:

    the PWM frequency of the pressure control solenoid/force motor sometimes changed depending on model year on certain transmissions, was there a general reason behind this? i want to say frequency always jumped upwards, never down.

    i've been operating under the assumption that a new PCS/FM was specified/installed that could tolerate a higher frequency to keep the actual line pressure closer to target, rather than swinging above and below target pressure. i get the feeling that the inductance of the solenoid was what allowed this to be possible?
    1995 Chevrolet Monte Carlo LS 3100 + 4T60E


  7. #7
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    Quote Originally Posted by gregs78cam View Post
    Yes getting the '7427 to datalog WBO2, and run your 4L80E is relatively easy. To answer your questions:

    1. You should have no problem using that '7427 to run the 4L80E. Just make sure it has a memcal with a chip with a $0E .bin burned onto it. I don't know if a V8 memcal is mandatory, as there are no fuel or timing outputs being used. But you should probably spend some time disabling any DTC's that you don't need. For datalogging and .bin editing be sure so use a $0E .xdf.

    2. Doing the above should provide you with all the parameters you need to tweak the 4L80E to your liking. Most all of the trans stuff is near the bottom of the Constants, and Tables sections. Attached is the .xdf that 93V8S10 made long ago, and I added few features to, I use it for both of my TBI vehicles.

    3. Anything out there that is "optimized", wont be optimized for your engine, gear ratio, or vehicle.

    4. I don't believe that feature exists for the '7427.

    Thanks!!


    Quote Originally Posted by RobertISaar View Post
    i seem to remember seeing both code references and maybe even a diagram or two of a "manual, normal, perfomance" shift pattern switch.... i'll have to look around to be sure.
    That would be awesome if you could find this. Please let me know if you do.



    Quote Originally Posted by billygraves View Post
    I'll put in a couple.
    In regards to the 4L80-E:
    If you wish to have ONE PCM or controller, you can. Since you have a 92 with the older BOSCH force Motor controls, you can move to the Holley Force Motor Controls BUT YOU MUST replace the Valvebody assembly (with aux valvebody) and Force Motor.
    The rule with the 4L80-E is to keep the Force Motor, Valvebody, space plate, and TCM/PCM as a UNIT. If you want to know why I can respond.
    In order to move your 92 TRUCK to the 94-96PCM controls I would suggest you replace the valve body, spacer plate, VB gaskets, and I would replace the internal and splice in an external trans harness WITH the PCM. If this were mine with a 540 cu in, I would HIGHLY SUGGEST you seek out a BIG BLOCK Valvebody. These Vavlebodies had a higher GAIN in Line Pressure and is better selected to control the higher power. I would suggest you enlarge or remove the checkballs for the direct clutch circuit that is for 3rd gear. I would suggest you enlarge the 2nd gear FEED hole in the spacer plate. One CRITICAL ITEM is you BEGIN WITH A CALIBRATION or FILE or BIN that is set up for a 4L80-E and NOT try to make the calibration into one. In the definition file there are MISSING BITS AND CALIBRATIONS that are NOT defined in the XDF file. In plain there are things you cannot see or change in the cal you need to in most cases. How I know this is this was my job @ GM.
    All good info. Thank you. Can you elaborate on why its a good idea to replace the force motor valvebody, space plate with this PCM swap? The 92 454ss came stock w/the 4L80E, so I would assume it already has the Big block valve body..?? The last thing I want to do is ruin the trans by doing this swap.


    Quote Originally Posted by billygraves View Post
    The XDF or Definitions has some trans calibrations. Wide OpenThrottle functions like this:
    There are calibrations for WOT or it is called KICKDOWN HI and Lo. It works like this. Once the TPS crosses this Kickdown Hi, the shift pattern looks at the KICKDOWN for the given commanded gear to UP or Downshift the trans. It does NOT look at the Tables. Each calibrator, well most of us, always set the tables the same as the Kickdown so when we looked at our shift lines in Excel spreadsheets it was the same and the best for us to observe/correct/suggest changes. Now, as soon as the TPS crosses the Kickdown LO TPS cal, the shifting resorts back to the tables.
    I think I understand this but I want to make sure. What you are saying is that when TPS >= "TPS to Enable Kickdown", it resorts to the "Kickdown" tables, otherwise it uses the "Normal Mode" shift tables, correct?

    It looks like the 7427 bins do not use "Upshift RPM vs Shift" as they are all zero'd out. This is whats confusing me. Is there a way to enable/utilize this table or do I need to calculate the RPM limiter as a function of MPH..? ie: based off trans gears/ gear ratio/ tire size etc..and then output the results to "Upshift MPH vs Shift" .. ?

    I found "RPM to Enter Fuel Cutoff" but since I'm no longer using TBI to control fueling this is useless.


    Thanks again for the responses guys!!

  8. #8
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    009F seems to be the byte used in 0E for the MNP switch.

    L5453 FDB $009F ; 59, PATTERN, MNP PATTERN
    ;
    ; b7 (not used)
    ; b6 (not used)
    ; b5 (not used)
    ; b4 (not used)
    ;
    ; b3 1 = ILLEGAL PATTERN REQUESTED
    ; b2 1 = 'MANUAL' PATTERN REQUESTED
    ; b1 1 = 'PERFORMANCE' PATTERN REQUESTED
    ; b0 1 = 'NORMAL' PATTERN REQUESTED
    ;-----------------------------

    there aren't too many places where it is stored to.... DTC77 also is applicable to it.

    i can't find any applications from the factory that used it though, so finding out the pin scheme required is going to be interesting.
    1995 Chevrolet Monte Carlo LS 3100 + 4T60E


  9. #9
    RIP EagleMark's Avatar
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    Quote Originally Posted by dubwise View Post
    It looks like the 7427 bins do not use "Upshift RPM vs Shift" as they are all zero'd out. This is whats confusing me.
    Maybe something is wrong with your bin? Or XDF? Or it's a manual?

    The "Upshift RPM vs Shift" is used in WOT as well or after MPH qualifier has been met. It's in the KickDown Mode Folder.

    Upshift/ Downshift MPH vs. TPS is in Normal Mode Shift Folder.

    EDIT: Ooops! This is a 4l60E I looked up in $0D

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  10. #10
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    if upshift RPM is set to 0 when in kickdown, then kickdown shiftpoints are entirely controlled by MPH. it wouldn't be the first time i've seen it in a factory calibration.
    1995 Chevrolet Monte Carlo LS 3100 + 4T60E


  11. #11
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    What is the logic if I set the "Upshift RPM vs Shift" .. or is it used?

    Basically I'm trying to figure out the best way to go about setting the shift points / rev limiter under the 4L80E section..

  12. #12
    billygraves
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    Last edited by billygraves; 06-30-2019 at 06:27 PM.

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    that may explain a few things...... like why TCC PWM solenoids have almost always been operated at 32Hz in every application that i've looked at. the PCMs look like they have always been capable of 64Hz, but i imagine that being a near-exact multiple of 20Hz could cause issues...

    this may complicate my 7730 TCM project a little.... i may have to have another microcontroller watch a 32-64Hz signal that i output from the 7730 and do some frequency modification while keeping the target duty cycle.
    1995 Chevrolet Monte Carlo LS 3100 + 4T60E


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  15. #15
    Fuel Injected! 1BadAction's Avatar
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    Quote Originally Posted by RobertISaar View Post
    009F seems to be the byte used in 0E for the MNP switch.

    L5453 FDB $009F ; 59, PATTERN, MNP PATTERN
    ;
    ; b7 (not used)
    ; b6 (not used)
    ; b5 (not used)
    ; b4 (not used)
    ;
    ; b3 1 = ILLEGAL PATTERN REQUESTED
    ; b2 1 = 'MANUAL' PATTERN REQUESTED
    ; b1 1 = 'PERFORMANCE' PATTERN REQUESTED
    ; b0 1 = 'NORMAL' PATTERN REQUESTED
    ;-----------------------------

    there aren't too many places where it is stored to.... DTC77 also is applicable to it.

    i can't find any applications from the factory that used it though, so finding out the pin scheme required is going to be interesting.
    I've wanted to do this on my 7060 ($D8).. The bin has tables and LOOKS like it would work, but no clue how I would go about tracing it down. I'm also working under the assumption that it would be a momentarily grounded pin that switches between the modes. Guess I could start grounding random pins to see if my shift patterns change. (quick, someone invest in reman 7060s)

    I guess I just can't shake the idea that there is a completely setup tow/haul mode in my factory ECM that I'm not using. Although I suppose it may be something vestigial that never was completed.
    Last edited by 1BadAction; 02-10-2014 at 09:25 PM.
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