In a large bowl, zest the grapefruit.
Juice the grapefruit into the bowl with the zest, remove any seeds that may fall into the bowl.
Whisk in the honey, tequila, mustard, olive oil, and salt.
Using a sharp knife remove the silver skin from the pork tenderloins if not already removed.
Add the thyme to the marinade.
Place the pork in the marinade and turn to coat completely.
Cover and place in the fridge to marinate for 2 hours.
Preheat BBQ to 400℉.
Remove the pork from the marinade and place on the preheated grill.
Sear pork on all sides for about 3-4 minutes per side.
Move tenderloins to opposite side of BBQ over indirect heat and close lid.
Cook until pork is fully cooked and internal temperature is 145℉
Allow to rest for 3-5 minutes before slicing.