What type of system dd you have. Boost trigger, constant on water injection or following fuel injector pulse. If it didn't want to start or idle or run off boost and you were running post-throttle body nozzles, its possible that the plenum vacuum was sucking water out of the lines. Did you have a solenoid between pump and nozzle or direct feed? If it was a snow kit you'd have most likely had a boost trigger point. It should never try to inject water below that switch point but perhaps yours wasn't wired correctly or mal adjusted and allowing triggering off boost too? It could also be that your nozzle size was just too ambitious and that if you weren't pulling fuel that you were just quenching the spark.