Short story: Replaced oil cooler gasket, and did an oil change at the same time. Cranked 3 times with DIS disconnected to allow it to build oil pressure. Reattached DIS now it suddenly won't crank anymore. Turned the motor over using crank pulley nut just to confirm it'll spin no problem. Long story: Disconnected negative battery terminal but left starter on sub-frame (out of the way to get better access to oil cooler from underneath, and so I wouldn't be disconnecting everything). Put everything back together, unplugged DIS and re-attached negative battery cable so that I could crank it a few times to build oil pressure. After plugging DIS back in it doesn't want to crank. Battery has been on a battery tender and has maintained 12.6+v and was cranking fast right up until it did not want to crank anymore. Why would it suddenly decide to crank one minute, and not the next minute? Recently I was troubleshooting crank but no start (ended up being crank position sensor), but I'm not sure where to begin with a no-crank issue. I confirmed the large negative battery terminal cable is going to starter mounting bolt.