A full manifold vacuum signal is routed to the EZL module as is the idle signal from the TVS. The EZL is programmed to disable vacuum advance at idle, and it keeps the idle timing fixed at 9 degrees as long as the idle signal is received, and this idle timing value cannot be changed - at least in any way that I am aware of. The rate of advance increase with engine revs CAN be changed with different R16/1 resistor values.

If you raise engine revolutions to, say 2000, and check ignition timing (A dial back light works best for this test.) you should see about 14 degress more advance with the vacuum line connected to the EZL module compared to disconnecting and plugging it. You can run the test with a vacuum pump, too, but the throttle must be above the idle stop so the TVS idle signal is not present at the EZL module.

There should be no problems driving with the EGR disabled, but if you have to get emission tested before it's repaired, there's a good chance that you will exceed the NOx limits or fail a visual or functional inspection.

Duke