I’m posting this because I’m just curious as to what’s going on inside the engine.
I’ve had my 88 XJS V12 for about two years now. I bought it barely running, and it had sat 7 years. PO didn’t know what they were doing, and the car ran super rich failing several smog checks before it was put into storage.
I got it running decently within 6 months, and have continued to restore it over time.
I switched to synthetic oil about 8 months ago, and try to drive it at least three times a week. I’ve put about 5000 miles on it now in two years.
I have noticed over the last year, not only does the engine run better, but i have slowly had to adjust the ecu leaner and leaner. A year ago, i had to set the ecu at halfway full rich to idle smooth. Now it runs smoothly with proper voltage numbers at only one click rich.