[grant lyon]

Basically suggesting you chase down potential collateral damage/failure from the original failure; work your way outward from the known failure. I'm thinking you now have an intermittent connection which opens only when the firing engine provides just enough vibration to move poor connections. Only going after the rly socket 1st because the original relay fried (probably a bad/fractured internal solder joint) and the connector is the next thing in line to be damaged by excessive heat before the hot relay failed open. Suggest you want to eliminate a fouled connector. Also, check connector sockets front and back to make sure sockets are still seated properly and leads connected after your removal of the original relay. Jumper diagnostics may help before you search for (and even potentially introduce) unrelated problems.