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Thread: New Member

  1. #1
    Electronic Ignition!
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    Mar 2023
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    Boise, ID
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    Cool New Member

    So I wanted to join the forum in order to get some help with tuning my 1999 c2500 7.4L Suburban. I just received my OBDXpro cable today and I'm hoping against hope that I can find an xdf and or ads file for my vehicle. From what I read already it sounds like my ECU is not too popular (service ID 16263494). I did search the forum and saw that way back a few people were trying to tune this one, but the threads end with no real finish or solution. I saw that HPtuners apparently supports this ECU but that is beyond my budget so any help offered me would be great . Thanks, Kenny

  2. #2
    Fuel Injected! ralmo94's Avatar
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    Feb 2020
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    What you can do, is swap in a ls computer, p01 service number 1220411. Known as the 0411 swap.
    You need conversion pinout, and both connectors. What I researched for the 7.4, is that most people successfully get to start and run fairly decent even though it needs tuned.

    This works due to gm keeping small block in express and savannah vans until 2003.
    That's the base tune you need, for a 2500 or 3500 express van with a 5.7 and 4l80e.

    In preparation for my swap I purchased a used pcm from eBay and gave a vin number for an express van, so it came with the popular operating system know as 2156. Price was about $80.

    You can use any 0411 from a pull yard as there are base files on this site.

    Most you pull it yards are about $30
    You could get enough stuff for a bench harness and program it before you do the swap
    No need to re-invent the wheel. But we can make it better

  3. #3
    Electronic Ignition!
    Join Date
    Mar 2023
    Location
    Boise, ID
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    Ralmo, Thanks for the reply. Did you do any tuning on the 0411 after you got it? My engine is a 7.4L and I have also modified it to a 496 (approx 8L now). I have been looking into the 0411 swap and I am going to hit the junk yards this weekend and see if I can get my hands on a 1220411 PCM. If my motor was stock and a 5.7L I would think that as you said the new PCM would be fine as is, but since My motor is so much different I am trying to see if I can locate more tuning data.
    Old school guy- 1957 Chevy 210 wagon, 1950 Buick Roadmaster, 1966 Buick Electra 225

  4. #4
    Fuel Injected! ralmo94's Avatar
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    I haven't installed mine yet as I have been out on the road for over a year, hoping to start soon within a month or so. I would say the first and main thing to change is obviously vats, and make sure you have correct injector data. Then you can copy over a stock 7.4 MAF curve. I have HP tuners and can help with that if needed.
    No need to re-invent the wheel. But we can make it better

  5. #5
    Electronic Ignition!
    Join Date
    Mar 2023
    Location
    Boise, ID
    Posts
    13
    Awesome! Thanks for your willingness to help. I will reach out later if I need help from you with the HP tuners side of things
    Old school guy- 1957 Chevy 210 wagon, 1950 Buick Roadmaster, 1966 Buick Electra 225

  6. #6
    Electronic Ignition!
    Join Date
    Mar 2023
    Location
    Boise, ID
    Posts
    13
    I have completed the swap! and it runs, but not real well. I did a lot of research and barely understand the process of tuning. I have been using PCM hammer and protuner (because I am cheap) But it looks like I am at a dead end with logging in order to get a good tune of the VE table etc. the swap was super easy and I made my own spreadsheet to track the pin swapping. Shoot, I even recovered the PCM from a soft brick situation that I am not sure how I created. So I am learning stuff.
    Old school guy- 1957 Chevy 210 wagon, 1950 Buick Roadmaster, 1966 Buick Electra 225

  7. #7
    Fuel Injected! ralmo94's Avatar
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    Glad you got it running!
    To get the VE dialed in, you need to fail the MAF sensor so it runs speed density.
    Did you adjust the cylinder volume size?
    Are your injector settings correct for injectors being used? That's where to start.
    Hope it helps.
    No need to re-invent the wheel. But we can make it better

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