My Tuning Journey (Using AI). Tuned for $80!
First off, I have been building cars and messing with cars for years. First time playing with an LS platform and I am getting educated at every corner. I believe in true DIY for almost everything but I had always drawn the line at tuning. I have had multiple cars dyno tuned in the past but they were all turbo charged. My engine is a Gen 3, 4.8, Truck Norris Cam, Springs, etc... I figured being NA I would try to tune it myself using AI. I am writing this to hopefully help someone else in the future. You can do this. I found my way through almost all of this via artificial intelligence.
First Start:
As I said, I got educated early about Blue/Red vs Blue/Green PCMs and unfortunately I had a DBW ECU with a DBC Harness and wanted to keep the DBC since my 58 Chevy Truck was already set up for it. I bought a Blue/Red PCM off of eBay that a guy had already removed VATS off of. I figured it would at least get me started. That PCM did get my truck started. I had an HPtuners MPVI3 that I had bought for this project. All was good until I realized that my ECT was reading pinned at 287. After hours of trying to chase the problem, I decided to go to the junkyard and pull another PCM. I can't explain why but that PCM also had the same ECT issue. So I thought for sure it was a wiring issue. I spent days pouring over the harness and I basically threw up my hands. After several weeks, I was back to believing that it had to be the PCM. So I got a 3rd PCM at the junkyard. I would not have believed that 2 PCMs were bad with the exact same issue, but they were and the 3rd worked.
In the midst of this whole process I ended up plugging in the PCM harness with the key on. I shorted one of the bad PCMs and also damaged the HPtuners module. It took roughly 3 weeks to work with HPtuners to get them to return the module for inspection. I knew it was bad and they confirmed it. They refused to work on it and the only option was to upgrade to the new MPVI4 for I think $250 and my credits were already locked to my old bad PCM. Essentially it would have cost $350 to get tuning again with HPtuners. Not going to lie, I was pissed. I take responsibility for shorting it. But their tech support is atrocious and wasted about a month of my life.
I started looking elsewhere. I don't like the HPtuners credit system but I wasn't aware of anything else. I started looking around and found PCM Hammer/PCM Logger/Tunerpro. I was intrigued that all of these programs are open source and free. The only thing that costs money was the OBD2 module. I went for this and bought a OBDXpro for $80 and thought I would give it a shot. If you are not familiar:
PCM Hammer - Accessible as a Windows App download. Used for Reading and Writing of the PCM as well as changing PCM Operating Systems. Supposedly there is a Github download that is more robust.
PCM Logger - Also a Windows App download. Used for datalogging. It did a great job except for when I needed to add my Wideband O2 sensor. Supposedly there is a Github download that is more robust, I could not find it. I was able to add my Wideband O2 and datalog via another tool called Universal Patcher that had some additional functionality. Universal Patcher actually has all of the functionality you need as far as Reading/Writing, Logging, and Tuning, but I only used it for logging with a Wideband.
Tunerpro - Used to tune all aspects of your PCM. There is a paid version but I don't believe that it matters for LS platforms. I will explain later.
Essentially the work flow is:
- Read your existing PCM with PCM Hammer. This gives you a .BIN file of all of the parameters of your PCM. In that file it will list the operating system of your PCM (and there are a few).
- At this point, you need to find an .XDF file (definition file) that matches the operating system found in the BIN file. XDF and base BIN files for most GEN 3 LS platforms can be found here.
- BIN and XDF files are loaded into Tunerpro.
- Editting/Tuning of the BIN is done in Tunerpro. The modified BIN is saved in Tunerpro.
- The new modified BIN file is written to the PCM via PCM Hammer.
- Start and drive your vehicle and log with your laptop with PCM Logger.
- Throw the log file into Chat GPT (or whatever AI you want to use).
Steps 1-3 are basically a one time step. Steps 4-7 will be completed many times.
This is where I hit my first hiccup. My working PCM had some old operating system on it that I could not find an XDF file for. It didn't exist. This sucked because the file that was on it worked and my truck was running. What I did find was a BIN and XDF file for a 5.3 LS with a 4L60E. According to AI this was close enough and I could make any needed adjustments via Tunerpro to compensate for my smaller displacement. I used PCM Hammer to switch from my unsupported operating system to a more common 12212156 operating system. AI walked me through the process on how to do this. 5 minutes later I had a base tune and a new operating system. I made the needed adjustments in Tunerpro for my displacement and basically had an idling truck. This step alone would have cost an additional $100 if I was using HPtuners because of credits.
It took a totally of 75 log files over roughly 4 days to tune truck. Starting with idle, cruising, part throttle, and then wide open throttle. If I knew a little more about what I was doing it would have taken 2 days. Chat GPT had me chasing my tail with idle issues (because of my cam) and smoothing of tables (don't smooth unless you know what you are doing). I found that the data I put into my table and then smoothed around the data had essentially reset the values I had just changed. This alone would have saved me time.
I will say this. Chat GPT was very conservative with changes that it made and I appreciated this (My worst case scenario was that it would want to make a big change and then lean out my motor. This was NA and not forced induction so at least I had that going for me). When I got to WOT tuning it basically told me not to do it unless I got a wideband. I appreciated that too. Once I had a functioning wideband I successfully tuned WOT and shifting parameters.
I would definitely do this again and feel confident enough to try this with forced induction in the future.
By the way do not buy HPtuners if you just want VATS deleted. This combination listed above will handle that much cheaper.
TLDR: Cheap tuning, Not a tuner but I learned a ton. You can too!
