This is a quick reference test to determine if there are possible issues w injectors OR cp3 pumps in the LB7 Duramax. It's always best to consult a manual for exact flow and return specs as this DOES NOT determine which injector, bank or if it's the cp3 that is producing the excessive fuel. This is only a starting point to determine if a condition exists. Other symptoms may exist such as; white smoke, fuel in oil, misfire, poor fuel economy just to name a few. Good luck and thanks for watching.