is the factory jeep gauge elec or mech? if its electric have you tried hooking the wire off of the sender to the jeeps gauge wire?? the guage will probally read incorrect but what do you expect, its a conversion. and i doubt there is a free version of software that can do disable the factory security and adjust parameters in the pcm... you can buy the sofware to do it 600 bucks give or take a few $, or have it dyno tuned for about 400 and gain the ability to drive your car, and the mpg,hp, and tq you will gain from that and you wont have to worry about learning a new program...
1987 5.3 4l60e Silverado - daily driver with A/C,P/W,P/L,TILT and HID projectors - also for sale @ $8,500
A poor man buy's it twice