The LR ECU will certainly work without the vacuum advance, because it has nothing to do with the ignition system, if you run a motor (any motor) without any form of spark advance you will encounter the problems you describe.
Hook up a timing light and rev the motor and see how for the spark is retarded at say 2000rpm.
If you dont have a computer (ECU) that controls spark advance, then you most certainly need Vacuum and Mech. advance to control spark advance, Regards Frank.

