Nissan Repair: fuel pump or electrical on 86 nissan d21 pu, dremel tool, accurate test

Question
QUESTION: My 86 nissan 6cyl 2wd has been acting up for last few weeks.  It started losing fuel while driving so I would be constantly stepping on the gas pedal to keep from dying on the road.  At first I thought it was a poor connection to from the battery terminal that righted itself with some jiggling.  This got worse.    I changed the fuel filter nothing improved.  The fuel pump also makes a loud noise and has began to continue to keep clicking with ignition on.  At first problem seemed to solve after not driving for a few hours. I have cut off the connections and replaced with new ones cleaned battery terminals.  Checked the pos connection to starter.  I then dropped the fuel tank check the connecter for fuel pump wiring and inspected the fuel pump. looked clean.  Tank looked free of corrosion.  Put it back and drove for a few miles before it died again.  While waiting for it to temporarily drive again, thought I would just check under distributor cap.  It was pretty rusty.  Took a dremel tool to clean it up but feel that it isn't responsible for the constant clicking of relay and fuel pump continued noise.  Took out the relay for fuel pump and also for main relay.  Got new relays for both of them. Dropped tank again ran the pump submerged in a bucket of water for a minute.  It ran fine.  But as soon as I connected it back to the connector on vehicle clicking noise continues.  I really like the truck a lot and want to solve the problem.  Lastly about 6 months ago I fried the computer by switching positive and neg on battery.  A mechanic replaced the computer and fuel injector with used parts.  Let me know what your prognosis is.  Much obliged,   Jamie

ANSWER: Hi Jamie -

While you had the fuel tank down and pump out, the pump should have been replaced. Usually when you can start hearing it loudly, it is failing, and although it starts the car, during use it could cut out.

Running it in water is not an accurate test, being that water has a different viscosity than fuel. In fact that might have done the fuel pump in.

Long story short, I would replace the fuel pump. Getting the genuine part from the dealer helps.

Hope this helps -
aloha
calvin

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

QUESTION: Evening again,

I plan on getting a new fuel pump but with the pump unhooked I hear the clicking noise from main relay as if it is energized and deenergized intermittendly.  Removed and clicking stops.  I don't see any information on what the main relay does or goes to in Haynes manual for truck but feel it is unrelated to fuel pump.  Also my front turn signals stopped working at the same time this occurred.  Rear work no problem. Head lights work.  Maybe they are on same circuit.  I dont know.  Thank you,  Jamie

Answer
Hi Jamie -

Yes, actually the main relay does go to the fuel pump. The relay acts as 2 circuits, One to run when you have ignition on for a few seconds, and other to run when car is running.

I think changing your fuel pump will do the trick.

Hope this helps -
aloha
calvin