Injector O-Rings

[misnomer]

Arrighty, got a fuel leak. It seems to be coming around the backside of the injector (fuel rail side). Tried replacing the O-rings, but the ones I got were kind of loose around the injector's groove, didn't resolve the problem.

Is there a specific way these need to be installed to shrink around, or did I just get the wrong o-rings? I picked these up from Car Quest, where (aside from the stealership) would be a good place to get some new ones?

[transient]

AFAIK, The o-rings will need a little bit of lubricant applied to them to get them to slide on, and also to prime them a bit. I think motor oil does the trick, but i'm not entirely sure.