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The engine does have a manual primer pump located on the fuel filter housing. Located next to the primer pump is the bleed screw.( be sure to remove it completely to prime fuel system . then after clear fuel comes out, reinstall screw and pump primer until hard)
Now if you had contaminated fuel ( water in fuel) This can cause the injectors not to pass the fuel through the injector tips. ( it just returns it to the tank)
I have also seen debris from a failed injection pump cause the injectors not to open , and also stick open. GM has a published bulletin regarding injector issues after replacing a failed injection pump. It is ( 08-06-04-029C )
Here is the description from the bulletin.
Some customers may comment on an illumination of the MIL/SES with one or more of the following symptoms:
Upon further investigation, the technician may find DTC P0087- Fuel Rail Pressure (FRP) Too Low stored in the ECM.
A ceramic high pressure valve ball fracture inside the fuel injection pump may lead to internal pump damage resulting in low fuel rail pressure. This condition may contaminate the common fuel rails and fuel injectors with debris. The fuel injection pump may operate, but with reduced output flow.
Tighten Tighten the fuel pressure relief valve to 100 N·m (74 lb ft).
This is not the complete bulletin, but as you can see if this has had a pump replaced there is a possibility for debris to enter the fuel system and contaminate the entire high pressure side of the fuel injection system .
This would entail a very expensive cleaning process, and replacement of fuel system components .( injectors, fuel rails, )
You can have the dealer inspect this per this bulletin to verify.