the computer is looking for signals from the carb. re: throttle positions, mix. control solenoid function, vent solenoid, fuel cutoff.
the throttle switches can be jumpered(as if they are on), but it will still need to see the others.
also- it is difficult to tune the weber to meet the emissions without the help of a carb. savvy smog guy.
i pulled the solenoids out of my stocker, stuck 'em in a little box, wired them up like stock, and mounted it kinda near the battery. that gave the ecm the right signals to keep the light functional(still looking at temp and o2 sensor, rpm, etc.).
light goes on w/ign. and out after start. like normal.
it will still function if other parameters get out of whack, like exhaust too rich, .........
i did pass smog, but had trouble with the idle emissions. took some tweaking.