Momentary effect loop works with one pedal not with other...

[JasonG]

I build a pedal that allowed me to have the effect always on or have the effect in a loop so that when I hit the momentary switch you got the effected signal. It works with my fuzz pedal not with my Zoom G2. I thought it may be an impedance problem so I added a buffer to the clean signal. No luck. Does anyone have any thoughts? I have it so that when it is on momentary mode the effects tail. So the output of the effect is always connected.
Thanks!

[guitarpedalparts]

Would you be willing to post a schematic, or a detailed description of the pedal?  That would be most helpful for diagnosing any mysterious issues.