1980 280ZX - Fuel pump CONTROL relay --- location??? - Engine & Drivetrain

Posted October 30, 201212 yr

Can anyone CONFIRM the location of the fuel pump CONTROL relay on a 1980 ZX?

Not the fuel pump RELAY, which is under the dash, passenger side, kick panel

But the fuel pump CONTROL relay. (designated: Fuel Pump Relay-2) in the schematic.

The EFI bible APPEARS to show it in the in-engine bay relay block.

The diagrams are wrong for my 1980, for starters I don't have an automatic transmission but I have a relay in the socket labeled "Inhibitor Relay, A/T", I have three sockets in the rear row, not two, although only two are populated, etc.

Here's what's interesting. With that relay PULLED, when I turn the ignition to the on position the fuel pump runs.

With that relay INSERTED, the fuel pump doesn't run unless I turn to CRANK (I have the wire to the starter pulled so it doesn't actually crank, also allowing me to HEAR the fuel pump running)

This is the same intermittent behavior I've had a few times --- hearing the fuel pump run simply when I went to ignition on --- suggesting this relay is failing

According to the diagram, this behavior is IMPOSSIBLE with the relay removed. The fuel pump can ONLY

receive power by way of that relay. Removed, there should be NO WAY the fuel pump relay can receive power, not in a million years.

Ok, so here's my current GUESS: There IS no "Fuel pump relay -2" as drawn on the diagram. (It would be a very fancy, and expensive relay with two separate coils actuating two different sets of contacts...

INSTEAD Nissan wired two "generic" relays to "build" a circuit which operates LIKE "fuel pump relay -2" would. That would explain why I have a second relay, despite NOT having an automatic transmission.

Such an arrangement COULD explain the fuel pump relay getting power when only HALF of the circuit is plugged in.

Now I've got to come up with a test to confirm my suspicion......tomorrow. It's late, I'm tired and hungry.

Maybe now some of you can begin to understand why I put five bullet holes in this car!