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Comment by muststopmyths | original | Claude Code and Codex reverse engineered my 1994 Jeep's ECU over a $3 Arduino [video]
[−]muststopmyths · 2026-11-15 Sun 16:14 UTC · link
can someone explain the root cause of the smog test failure to me ? it sounds like the car was using a California smog test-specific fuel map at the speeds of the test. Wouldn't that make it pass the test, not fail it ?

very cool project anyway.

[−]threetonesun · 2026-11-15 Sun 16:34 UTC · link
Yeah doesn’t really make sense, there’s very likely a mechanical issue the LLM “fixed” with a richer fuel mix. But also it’s a 94 XJ the reason the CA map was there was probably because they got abhorrent gas mileage without it.
[−]bflesch · 2026-11-15 Sun 16:57 UTC · link
You can adjust the mixing ratio of fuel and air in a way so that the exhaust has reduced emissions. This will reduce performance of the car but allows the exhaust to pass the emission tests.