cummins isc300 prime issue?

cummins ISC prime issue?

07 Pete 340 with cummins ISC300 (manufactured in '06 so pre-emissions)...last week I started it in the morning as usual & let it warm up(it was cold outside so I went back into the house)...after about 5 minutes of running I heard it kind of sputter a second and then die...I went back out & tried to restart but to no avail - turned over great but no fire...after about 15 minutes of trying I broke out the ether cuz I had a load waiting and things have been pretty rough after being down for a week replacing the turbo, cac & muffler last week...it started and I hit the road...ran like a dream all day...next morning-same story...the next day (yesterday)I didn't give it the chance-I started it, held it about 1200 rpm's for a few minutes & hit the road, no problem...off today so I decided to test it-it died. Fuel filter only has about 10k. on it but I pulled it off and fuel was about 1 inch down so it's losing it's prime? but I filled it up & still no start???...electronic lift pump that I can hear working...It has been pretty cold here in the mornings (30's which is cold for Houston)...wondering if this could affect it? hate to keep shooting ether to it but I gotta work!!! anyone have any wisdom or advice?