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duxthe1 · #3 09-02-2024, 02:23 PM

My adapter came in and I was able to read both eproms. The C36 chip was a bit finicky and I had to try reading it as several different versions of the chip before I landed on one that would verify the read. With both both chips read it was time to dive into the mapping.

The first map I located was a big 16x32 that I think is the air mass transfer function. This map is in the 2.8L file but is not in the C36 file. I beat my head against this until I concluded that the C36 has several large 2D graphs in the same location and what I suspect happens is the C36 computes this from two 2D maps (air temp and sensor voltage) instead of looking it up from a 3D map.

The next map that I found that looks familiar is what I believe to be the fuel map. This same map shows up in the C36 file. Its not in the exact same location but its within a few dozen bytes. The maps, while very similar, are also not exactly the same with the C36 file having slightly higher values which further supports the idea that this is the fuel map.

Another map of importance I wanted to find is the ignition map. There are a few different maps that I located, but of the group one looks more like an ignition map than others. Like the fuel map, these maps are close to the same location in both files but the C36 map certainly looks more aggressive. I don't have any factors or offsets to define the axis or the data but dividing by 1000 gives plausible values for the whole map.

There are quite a few other maps that are easy to spot in the files. I'll likely spend some time cataloging them to swap them into my "tuned file" without actually knowing what they are. If the data is different but similar enough to pass a sanity check then it should probably swap over. There are bound to be maps for things like accel enrichment and cold start enrichments that I would not be able to recognize. I think the best approach is to try to get them all.