I'm working on a 1999 GMC Sierra (90s bodystyle) with a 7.4L engine. It hasn't been quite running right so my uncle replaced the ECM. Now, it won't start with the new computer. It's a reman computer from AutoZone that was supposedly programmed based on his VIN number. Is there some sort of computer re-learn or security learn that needs to be done before it'll start? It cranks, but doesn't pop.