No risk at all... only risk would be if the engine was making too much power, as Y30 is part of the overboost safety circuit. Or too much boost, anyway. It's generally not a great idea to leave it bypassed long-term, in case the turbo wastegate fails closed and you get excessive boost. Even then, on an old injection pump, the possibility of injecting enough fuel to cause damage is pretty remote!

If you test both ways, with the ALDA disconected the times should be 3-5 seconds slower (from 10-12, up to 14-16). I bet you're a good candidate for an ALDA adjustment too...