Furnace question

I live in a 75 yr old house and have been working recently in my basement sealing up a lot of air leaks with spray foam. I actually foam sealed all the rim joists shut to get rid of draft, but I now found they were a source of ventilation in the basement because this is a balloon frame house so the rim joist cavities run all the way to the attic. Well our Furnace has been acting strange since I did this work and it made an extremely odd noise today along with smoke smells upstairs. We had an HVAC look at it today and he said by tightening up the basement air leaks(specifically the rim joists), we were not allowing the furnace to breath. Could this also cause sediment or build up in the oil line if the furnace was working harder to operate because he said there was a restriction and oil was not flowing well. We did have an oil delivery two weeks ago so maybe that stirred up gunk in the tank. So he recommended finding a new source of ventilation such as putting an open vent in the basement stairs door but I'm wondering if that alone will solve any further issues. Thanks for the replies.