Fuel pump problem (?)

[Mach30]

About a year ago, my grandmother passed away and she left me her 77 280z that she bought brand new off the showroom floor. It hasn't run for 10 years or so, so my dad and I tried to get it up and running. We emptied out all the old full and put new in, replaced oil, oil filter, fuel filter, plugs, wires, cap and rotor. Still wouldn't start. Figured out the pump wasn't pumping. Replaced it, but still nothing. Figured it was a bad relay and couldn't find a replacement. So I ran a switched hot line straight to the pump. It finally turned over and ran! Not well, but it ran. I finally found a new relay, installed it today, and reattached original wiring. Pump still won't turn on, though. Do I need to chase these wires, or could the issue be something else? Also, what else does this massive fuel pump relay do? It is too big to be just the pump, isn't it? Thanks for any and all information!

[Zed Head]

1 hour ago, Mach30 said:

 Pump still won't turn on, though. Do I need to chase these wires, or could the issue be something else?

The simple way to test the pump power circuit is to disconnect the small wire from the starter solenoid then turn the key to Start.  The pump does not "turn on" when the key is on.

Download the wiring diagram for your car and study it.  Find the connectors for the pump power and clean them up.  They might be corroded.  There is a full test procedure for the relays in the FSM also, I believe.  It also describes the other functions of the relay, if you're talking about the combined EFI/fuel pump relay.  That one is not massive though, so not clear which one you're working with.  Can you post a picture?

[S30Driver]

On the 77 280z, there is a fuel pump switch built into the AFM that is activated when the flap moves and air is drawn in.  A safety feature should the motor stop, such as in a accident, the pump is shut off.    Zed's suggestion to unplug the starter solenoid and turn key to start bypasses this.   Something to look at depending on what you find.

The rough running is likely partly due to gummed up injectors after sitting for 10 years with fuel in them.  

[Mike]

I received a donor 280z many years ago.  I had very strange problems until finally replacing the fuel injectors and soft fuel supply hoses.  The old hoses can deteriorate if left sitting dry for so many years and pieces can get stuck in the injectors.  If you do buy new injectors, I recommend replacing all of the fuel supply hoses (from the fuel filter to the engine) before you make the investment.  The fuel line from the tank to the engine isn't as important (until later) because the fuel filter should catch any debris that will clog the injectors.

Here are a few pics of my install:

 

 

Here are links to the files for your 77: