Power To Fuel Pump - '85 Nissan 720 Pick-up, Automatic Z24



178K miles and a little rough around the edges, but all-and-all, a solid little truck. A few mos ago, I was coming out of the supermarket and it stopped dead in the left lane after doing some coughing…obviously gas starved. Mechanic found no power to fuel pump, but while he was tracing the electric line it somehow powered up again. I changed the fuel pump myself since existing was original. It happened about 3 more times in the space of a month, but it would always start up within a minute or so. (This only happens at start up or shut down, can’t rule out either.)

After start up, the car will go so far, then starve and quit. Then about a month ago, it did the no start up right away thing after I had gone about 1/2 a block. I listened when I turned the key. I heard a relay in the carb, but there are two (one left exposed) under the dash and I could not hear them nor the elec. fuel pump clicking. I had to get a tow, but of course it started when my mechanic went to check it. This is what makes it a difficult problem.

I wanted to install a switch to put power to the pump so I can get off the road if necessary, and a 12 V little light so I can determine when it is exactly the power is stopping, so I can best analyze. Wayne’s, our electrical tracing expert, wouldn’t do the job;liability they say.

So: there are the start switch and two relays that engage the fuel pump. I don’t know if anything else is in the line. The switch turns on the cranking, and the carb clicks, so I don’t think it that. Should I just change the two relays and hope for the best? My thot is that there may be something else that stops the gas pump, maybe if the idle gets too low and there’s some kind of safety shut-off. I don’t have a shop manual to determine that.

I don’t want to give up the car, and could really use some thinking advice. (Wayne would have done the job if he didn’t retire; not the same with younger guys :(. I’m having a difficult time giving up on this, but could use any questions or answers advice!


My suggestion is to replace the power wire to the pump ensuring all connectors and connections are clean new and tight.

Where any splicing is done ensure you use heat shrinks. Forget using tape on an outside splice.