Crank but No Start Issue

Hello,
I store my truck in a non heated shed in the winter so i take my batteries out (it gets -25) in the winter where I live. I went to put them back in to get the truck fired up and long story short I made a mistake hooking the batteries up and a terminal jumped and made a large spark and melted a battery terminal and grounded out 3 of the batteries so I replaced all four. After hooking them up properly this time the truck would crank over but not start. This truck I believe has a small fuel leak that causes it to lose prime, somewhere probably a check valve so when it sits for a month or more I usually need to hit it generously with some starting fluid and its a rough start but it always has fired up. This time we hit it with either and it would just crank and sound like its about to go and then slowly die never actually firing up fully. I am guessing it just lost its prime. I ordered a small vacum pump and will be taking off the return fuel line before the filter housing and sucking the fuel from the tank all the way through and hopefully then it will fire up. Is there a way to check if it is primed or not?
This tool wont be here for a couple days. Since i messed up the batteries (tho i never turned the key over) could it have shorted something out (fuse, Relay) that would cause it to not pump fuel or a sensor that doesn't turn on if so could you point me toward that particular fuse. I dont know to much about trucks but am handy and can do my own work if pointed in the right direction. Looking for other ideas i can check while i wait.
I have spin on filters that hang below the filter housing i will be taking them off to see if they have fuel in them, if the check valve is bad at the filter housing would this cause all the fuel to drain out of the filter or no because the filters are lower than the filter housing and would have to go against gravity? Also will be looking at the check valve in the back of the head on the return side. PS what is the best way to check a valve?
Just curious what you guys think. sorry if this is pretty beginner stuff, just not sure where to start besides the fuel priming. Thanks in advance.

The truck is a 1994 international 9400, with a DDEC 11 12.7L detroit 60 series engine. only use about 3 months of the year for harvest.

 

Ok i will check that tomorrow, also I checked all the fuses in the cab but totally blanked on the one in the battery box i will check that to. and i guess there should be some more by the ECM or by the Firewall.
dumb mistake with the batteries, in a rush, How did you know that the ECM was fried? Aslo would this affect the SRS or TRS crankshaft sensors. Could they "short out"?
really appreciate the reply, something like this I don't want to pay someone to check a bunch of stuff that I can do myself until I find the real problem and if its difficult to fix then bring it in and have them fix that particular part.
thanks

 

I can check the power for the ECM at the 5 prong plug in correct? remove it and test hot wires with test light. I read that its like 2 hots and one ground.

 

this was so long ago but I forgot to reply. Thats exactly what it was, I always saw that fuse but figured it was added on to power some other accessory junk. But it was exactly like you said, I think my cables slipped and made connection with the wrong terminal on the battery and blew that fuse replaced fuse and it fired right up. Thanks a lot! sorry for the late reply lol