we ran out of oil today and the oil people wont come until tomorrow. i put 4 gallons of diesel in to last the night. i bled air from the line that feeds the oil and restarted the furnace. some smoke came out of the ?firebox? and the furnace sounded as if it was sputtering or hesitating almost. upon restart and bleeding the line that feeds the oil some more the furnace began to smoke more and rumble quite loudly. it is off now, what could be causing the furnace to rumble and smoke? did i damage anything? i have used diesel before with no problems.