Chevrolet Spark Oil Witness Light helps ...

I personally, in addition to a little oil, armo with Molycote, insist, I would send to try the pump in a test bench, if the crankshaft it is clean and lubricated they do not have to scratch, that is almost certain for lack of lubrication, covered ducts, failure in the pump and a large leak in one of the oil galleries. I would not assemble it again until the cause of the lack of oil pressure.
Luck

You can get the crankcase connects in the oil gallery get a hand pump and place the engine at medium height and when you pressure the gallery you can see the lubricant loss in case you have a fissure that you can not see inside the engine (put a tray under the engine and keep the lubricant clean)

Thanks friend, it turned out to be the crankshaft caps ... already replaces them and problem solved must have been for the first start that worn but so far it has not returned to the engine ... greetings ..