Pump Relay
 

Alright guy's. 76 280Z. Where the heck is the fuel pump relay located at?

Under the hood, in a black box on the passengers side. Can't remember which one exactly though. What's the issue at hand? The relays don't really go bad much.

The pump won't turn on with iggnition. It will if we hot wire it with a toggle switch.

http://i48.photobucket.com/albums/f2...060506_002.jpg

http://i48.photobucket.com/albums/f2...060506_001.jpg

The fuel pump switch is in the AFM. It doesn't turn on until the engine is turned over and the sucktion pulls the AFM flap open.

Are you sure??? Every time I start the car I hear the pump activate as soon as I start to turn the key. The sound comes from the rear of the car.

When you crank the car to start an EFI S30, the relays and logic that normally control sending power to the pump are bypassed. When you let off the key from "Start" to just plain old "On", the logic comes back into play. The fuel pump relay is in that box naviathan mentioned. It doesn't close unless your alternator is actually producing a charge. I found this out the hard way once testing the pump first, then the relay, and then the next piece upstream in the schematic was the alternator. Mine was dead.

Though I haven't looked at the schematic in awhile, I do remember there were more pieces to the overall logic circuit powering the fuel pump, and I wouldn't be surprised if naviathan's right about the AFM being one piece of the puzzle. If you don't already have a schematic for the car, you'll definitely want to get one. It's pretty easy to work on with that diagram, and just about impossible without it.
good luck,
Dave

would be nice to have that black box under the hood like my s130. but it's just not there.

I wonder where it is on the '76s? On my 78's it's always been on the passenger side (all lefthand drive cars), mounted on the fender well, just behind the wheel, just in front of the battery and just in front of the inspection lid for the battery. The fusible links are mounted to the box, too, and two major wire harness plugs are clipped to it.
Really weird for them to have moved it, but there must have been some reason...
Dave

Fubar, has the car ever run since this person had it??? Maybe the relays have been removed.

yeh. we start it up once a week to keep motor fresh, just runs rich since the regulator is Fubar and the fuel pump in on a toggle switch

But has the car started on its own without the toggle switch??? Was this car picked up from a junkyard? If so then there's a good chance that the relay was picked out of it which would explain why you can't find it ;)

no, it can start on it's own, till the gas in the lines runs out. And no it was not from a junk yard. just a bad relay or wire i have to track down.

I am also having the same problem with my 75Z (Will not start). So with the ignition key in the "ON" position I manually opened the flap in the Air Flow Meter and I could hear the pump spin up everytime I poked the flap open. I could also cup the inlet hole to the AFM while someone cranked the engine and I feel good suction. and I watched the flap come back to the home positon when I pulled my hand away.
I removed the gas tank inlet hose that goes to the fuel pump and plugged it with a wooden dowel to stop the gas flow. I removed the front half of the fuel pump (Four screws). I noticed that the Screen was pretty clogged so I cleaned it with break cleaner and figured this will fix it. Well I still cant get it to start. So I pulled the outlet hose from the fuel filter and there is no fuel comming out. I don't know at this point if this was my problem all along or wheather I hosed something up when I put the front half of the fuel pump back on (The fuel pump has "four" barrel type tumblers in there with a geneva type gear spinning them around). Next I guess I will pull the outlet hose off the fuel pump to see if fuel makes it out. I'm thinking maybe a bad fuel regulator? Any other ideas?.. PS: Sorry for hijacking this thread.

I normally use a razor knife to cut the silicone on the air flow meter cover and check usually find the switch contacts to either be dirty or the springiness has weakened over time. Usually just takes a slight tweak with some needle nose pliers to get it proper.