I’ve got a Mack cxu613 with an MP8 engine 10 speed manual transmission. After Harvest the truck was washed and sat for a few months out in the elements(no available spots in shed). Temps swung between 30 degrees to -30 a few times during this period. Needed to bring into shop for general maintenance. When parked and washed it ran fine. On a warmer day I plugged in block heater and battery charger for batteries. Would crank but not start. Figured fuel was gelled up so replaced both filters and batteries. Tried priming but primer button never got stiff like they should. What’s my best bet for getting it running or diagnosing what could be the issue. Has been in my shop for the better half of the week. Only active fault code is dpf sensor which was rubbing on harness and shorted on metal.