text disintegration problem

i’m trying to make text disintegrate from left to right using a blend texture and mapping it to particles and time. the problem is that the disintegration starts fine…1 letter at a time, then all of the sudden all of the text that is left disintegrates at once.

i’ve tried negative frames, more frames to emit particles, etc., but blender keeps waiting until the last 40 or so frames of the particle emition before it starts the explode modifier which results in the situation above. when i turn off the blend time map, it explodes like normal…then add the map to make it go left to right and starts off good, then what is left goes all at once.

any help?