Inj fuse keep blow out

I have 2000 Quest, the problem is my Inj fuse keep blow out everytime, I'm not sure when it blow out(turn on the engine or turn off the engine) Anyway, I have to change my Inj fuse everytime. However, it never blow out while I drive.
I did diagnostic test but mechanic can't find out why Inj fuse keep blow out, he think the wire is short somewhere. Anybody has same problem? is that possible computer box or?

get another mechanic
... if he can't trace the short circuit in the wiring...