Nissan Repair: The fuel will not go to the engine., fuel pressure gauge, vent line

Question
QUESTION: The fuel will not go to the engine. The engine will start when adding fuel directly to the carburetor. The pump has been replaced. When I try to start the engine the pump sound only for a short moment, but then stops. The fuse is in good condition as well.
Is there anything that I am missing?

ANSWER: Hi Cesar

Can you tell me the engine size, year and model of your Nissan?


Thank you
Calvin


---------- FOLLOW-UP ----------

QUESTION: Hello Calvin
Thank you for helping me.

Engine size is a 4 cylinder engine.

Its a 1993 Nissan Pickup.

Answer
Hi Cesar -

OK. Thanks. There are some steps that need to be taken for testing. The pump going off after a few seconds is normal. When you turn the key on the pump will feed until the system reaches about 45PSI and then the regulator will shut it off until the pressure drops.

First of all, remove the main fuel line going to the front rail. Place the hose in a container. Turn the ignition on and then check if you see fuel coming out. If so, then observe the volume. There should be about a cup of fuel for every 3 seconds. It would also help to get a fuel pressure gauge and check to see if you have about 45PSI at the rail.

If you do not see fuel coming out, check for blockage in the line, a broken fuel line of vent line, or a clogged filter.

Let me know how this goes -

aloha
Calvin