I just replaced the injection pump on my wife's 2016 ram. Had her take it for a drive, it started and idled fine at first. During her drive it started acting weird. Her words, not mine. When she went to back into the driveway the oil pressure light came on and the pressure dropped to zero. Did I mess something up possibly, or what should I be looking at. If its the oil pump wnere is it located. I looked at them online and they look like the are external. Any help is appreciated. I'm trying to keep this truck on the road till I can find her a 2500 with a Cummins.