First - and easiest - get a fuel pressure test gage that will connect to the Schrader valve on the fuel rail (the RENIX is a GM-style valve - I don't know about later...) Most fuel pressure test gages have a bypass port on a button - which will allow you to bleed off the system pressure. Jump the relay, push the button, and drain it into a convenient container.
Second - but this should be done about about 2/3-tank or less - pull the access plate for the fuel pump (upper front centre of tank) and syphon it out through there. That will give you a 4" hole to work through. NOTE - if you do this, use a BRASS hammer and a BRASS rod - I don't want to end up reading about a spaceborne XJ...
Alternatively, you can pull the feed line off of the fuel pump at the access plate, and hook your drain hose up to that. Don't let the pump run dry for too long, or it could overheat - then you go buy a new one.
Oddly enough, I'm thinking about adding a "supply" pump and tap, since I end up playing "filling station" for my lawnmower and some other goodies, and I'd like to keep everything simple. Have to work out a safe way and place to do it...
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