[ssgharkness020147]

Air your tires up to the proper amount. Then disconnect the quick connects over night, when you go back the next day check the pressure at each tire with a pressure checker. This will eliminate the possibility of rim/tire leaks. While the tires are disconnected, pump the system up (just the lines) to 45 PSI, wait five minutes and see how much the pressure drops. 5 PSI or less if normal. Anything more and you may want to investigate it further.

I would be willing to bet you need new front lines, from the T connector to each spindle. Geared hub input and output seals can cause leaks.

The CTIS valves can leak.

The blow off valve you are reffering to is the over pressure relief valve, if it is not working correctly you will hear a popping sound as you try to air up your tires. You may also want to check for leaks on the lines coming from your manifold.