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Thread: 99 Isuzu 3.5 anyone know about these ECUs?

  1. #1
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    99 Isuzu 3.5 anyone know about these ECUs?

    To start, I'm new to this board so hopefully my project I'm embarking on will be welcome here and there will be folks here both interested in helping as well as knowledgeable enough to help me in the areas I'm lacking in.


    As my day job I work as a software engineer. I primarily work in languages such as puppet, go-lang and Ruby and focus heavily in a Linux infrastructure-oriented development environment. I also know C/C++ and have spent a lot of time toying around with the arduino platform. This doesn't necessarily I"m ready to take on everything this project will most likely present me with but it shows I'm no stranger to computers and how they work. I also spent a few years as a professional automotive tech, I have been working on cars basically my whole life, am good with a wrench and am not afraid to get my hands dirty.


    Now about this project....
    I am a huge Isuzu enthusiast (yes we exist) I grew up in my dad's truck and now have the pleasure of owning my own. They're ultra reliable, easy to work on, and can take on just about anything off the road on the trails. This isn't to say they don't have their issues. Probably the #1 problem found on the late model Isuzu V6s (named 6VD1 3.2 and 6VE1 3.5) is their tendency to trigger CEL for a P0401 which is EGR flow insufficient. This is often times fixed by replacing the GM EGR valve, cleaning the intake side of the tube as it sometimes can get clogged with carbon or sometimes both. I want to try to establish a 3rd way of fixing this problem. And that being to delete the EGR system all-together. The benefits to this would include both lowing air intake temperatures and would lessen the amount of carbon and other junk being recirculated into the engine.


    You can get an EGR delete plate for a pretty good price as this specific valve was very common among late 90s GM cars/trucks but doing this isn't enough to remove the problem as unplugging the EGR valve will throw a code of its own. This means I will have to get personal with my PCM. The PCM used on the 98/99 troopers can be found under the radio behind some trim. I originally was under the impression that despite all the delco electronics throughout the truck the ECU was not one of them. This is due to a complete lack of information on the PCM, and there being no established tools that can interface/program this PCM except for the TECH 2. This most likely means I will have to reverse engineer it myself. I've been doing a lot of reading on the topic and I think the best way to go about solving this problem would be to disassemble the PCM, locate the EEPROM that contains the map for the EGR system. import this EEPROM onto a computer, remap the EGR to be completely flat and therefore accept all ranges of flow when it runs its EGR test. And delete the DTC directly related to unplugging the EGR valve from the system. Simple enough right? LOL


    I pulled my PCM the other day to start studying the internals and figuring out how it works (this PCM not be touched. I will be pulling a computer from a donor truck to experiment with and remove IC chips) What I found was somewhat surprising...

    I see a whole lot of delco parts on this computer. Now whether or not this is a PCM manufactured by Delco for Isuzu still remains to be seem, all I know is its made in Singapore, and contains a few Delco chips. Perhaps someone can chime in on this.


    Next I started to pull numbers and began identifying chips. For simplicity I have colorcoded what I have.

    I have missed a few chips so I'll have to pull it apart again and get the ones I missed... But as it stands now What heres what I've found (start at top move clockwise):


    LIGHT GREEN: Delco 27833
    LIGHT ORANGE: Don't have numbers for these. need to pull apart again
    RED: AMD Am29F010 this is some sort of flash memory, holds 1 Megabit of information, found a pdf on it here: http://noel.feld.cvut.cz/hw/amd/16736f1.pdf
    BLUE: Some sort of Motorola chip, has masket E87J http://matthieu.benoit.free.fr/cross...la/Maskset.htm
    GREEN: DELCO 66285 can't find much more info on this. Just a bunch for sale
    ORANGE: DELCO 40854 even less info on this one comared to the last.
    BLUE: Another moto chip. masket E57S http://matthieu.benoit.free.fr/cross...la/Maskset.htm
    PURPLE: THAILAND 50610 given its structure I believe its some sort of EPROM. Can't get much more info online about it. No pinouts etc.
    LIGHT BLUE: DELCO 51862 once again just a bunch for sale online, noticed they came in a few other ECUs saw one in a saturn and mitsubishi, weird.
    YELLOW: Don't have clear numbers on these 2 have to take it apart again
    PURPLE: Same as the other THAILAND 50610
    PINK: M83AD can't find anything on this
    LIGHT PURPLE: 16132083 don't know the manufacturer for this one. found a couple for sale online


    So at this point I think my best leads are the AMD flash memory and the 2 Motorola processors. If anybody can help get me more info about anything or what I should do next anything is appreciated!


    Thanks!
    Garrett

  2. #2
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    The memory chip is the amd one. You have to pull it and read the content. Than install socket for easy hacks.

    The processor is motorola 68HC11f1. Easy to crack.

    Do you have external pictures of pcm and connectors.

  3. #3
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    So you believe the AMD flash chip will contain the EGR map? If so that is what I'll do, I'll find a reader for it so I can hook it up to my computer.
    Here is the outside case for the PCM there is no manufacturer info that I can tell. Just an isuzu part number
    20181027_115151.jpg

    It has 3 connectors (not shown in picture) 1 red, 1 blue and 1 white all the same size

  4. #4
    Fuel Injected! jim_in_dorris's Avatar
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    Good news is 68hc11's are well documented. Hopefully your assembly skills are up to the task. I also think that a picture of the exterior of the ecm showing connectors might be of help. Grab an easy chair and start researching how the chevy guys dis-assembled the prom. IIRC the thirdgen site has some good writeups.
    Square body stepsides forever!!!

  5. #5
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    Here is the pinout for the 3 connectors for the PCM
    2012-04-26_132003_conn1.gif
    2012-04-26_132017_conn2.gif

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    Interesting. That looks very similar to the Daewoo / Delco PCM that I obtained years ago with a 2000 2.0 DOHC GM / Daewoo engine. The big brother to this four cylinder is a 2.2L engine. A version of the 2.2 is available in the Trooper. Looking at pictures of the 2.2 and 3.5 Trooper ECM's convince me they are very similar.

    When I started playing with this ecm there were few tools built that allowed one to attempt to unlock and download the pcm code through the diagnostic port. Today there are a few. One might allow you to use the GM algorithm to cread a key from a manually requested seed. I don't know if this is the best approach but it is one way to start.

  7. #7
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    Looks like you're definitely right! If anything the outside box and connectors are identical to the 98/99 trooper PCM
    s-l400 (1).jpg
    s-l400 (2).jpg
    Last edited by CyrodiilSavior; 10-28-2018 at 02:38 PM.

  8. #8
    Carb and Points!
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    Small update: a friend of mine sent me this apparently there is a hidden plug underneath the plastic bit seen in the pictures above. I saw it on a couple other GM ecus from around this time period. Is this possibly a way to interface/program the system?
    44931129_2301240213238033_5438219789841465344_o.jpg

  9. #9
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    The plastic bit is usually called a "knock filter." In older ecm's the knock filter contained circuitry to filter noise from the knock sensor so the ecm could focus on real knocking. The plug is standard to other GM ecm/pcm units using a similar knock filter design. I don't know of anyone using that plug to access the code.

  10. #10
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    It is not a data port, it is an analog filter plus an amplifier, and an analog-to-digital converter.

    Same part is used on the 2.8/3.1/3.4L P66 PCM's. You have a P6-style computer, but it's got P66 style programming. Not currently well studied-but you might start with the flash routines for the 94/95 OBD 1.5 computers used for the 3.4L V6 and LT1 V8 computers.

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