Pull the air cleaner and run the engine. you should see leaks dripping from either an injector at the hard line, or at the IP-side of each hard line. Either way you would see fuel running down the valley pan below the intake manifold.
Fix that leak - tighten the leaking fitting.
You can also shove a paper towel down under the intake manifold behind the IP, so you can see if it soaks up diesel.
Once you fix that problem, then you want to look into a new CDR grommet at the back of the CDR going down into the valley pan - don't want water/fuel going in there.
Check back there as well when troubleshooting - if you see a "pool" of fuel back there, you will need to clean out the drain plug. There should be a small round drain plug with a 3/8" square hole in the center. This is straight back behind the CDR(at the back of the intake). If that's plugged, use a screwdriver to clean it out. You don't need to worry about damaging anything below that hole - it's just a cast-iron boss that lets fuel/water go backwards and drain off the passenger side of the engine.
