Nissan Repair: 1990 Nissian p/u 2.4, fire fuel, nissian

Question
We recently did the top of the motor(Head reworked, gasket, water pump, timing chain, etc.  The truck was running ok, just seemed a little rich smelling when cut off.  The only way it will crank now is if you prime the  mpfi throttle body with a little gas.  We have checked getting fire, fuel, spark and comp in time. Could it be a sensor?  We don't know much about fuel inj. just Carburators. thanks  

Answer
Hi Debbie,

Sorry this took so long. I take Sundays off from this and besides wanted to chat with my guys at the shop. We all concur that it's the fuel pump or pump regulator. Although you are getting fuel at idle, we feel that the fuel pressure is not keeping up with demand. The fuel pump works on a demand basis. It will come on until the desire pressure is obtained then shut off until the regulator calls for more pressure. I think it is jamming until when it reaches full pressure. I feel changing the fuel pump will eliminate this issue!