I have been working on the '77 280z I picked up a few weeks ago and went about removing not 1 but 2 aftermarket radio harnesses. While doing so I saw a previous owner had used 2 wires that were spliced in to the ignition switch at the key to 2 wires going in to the fuse box, a blue w/white stripe wire and a white w/blk stripe wire. I removed the wires and repaired the splices in the wires going in to the fuse box. From what I have read so far this was done either because the fuel pump relay is out or the EFI relay is out. How would I know which relay is out? Due to the cost of the relays is this a safe method of powering the fuel pump and EFI system? My guess is no. I want to make the car right since it is my daily driver right now and not put the car in danger of burning to the ground. Any info and guidance is greatly appreciated.

I have an update. The 2 wires in the ignition switch that the wires were spliced in to was a blue w/red stripe anda black w/white stripe. I have just purchased a FSM on CD as the FSM book I have is for a '78 and have already discovered a few differences between it and my car. Best to have the correct book. Any ideas around this?

So I have another update. I checked the to see what kind of signal came out of the 2 wires mentioned above connected to the ignition switch if I turned the key. Weather the key is turned or not they complete a circuit and when checked for voltage at both wires there is nothing. One surprise came when I turned the key, heard the fuel pump run, started the car and it ran for 3 seconds very smoothly and then died. This leads me to believe my ignition relay is okay but now could be all sorts of other things. I have seen other posts about the AFM possibly being bad. Please post any ideas you may have.

I have read here that the fuel pump will kick on for a bit, but if positive feedback is not received (e.g. Oil pressure pumped up) the fuel pump will kick back off to prevent running when the motor is off. Maybe check your oil pressure sensor connections?

The 77's have a fuel pump switch in the AFM, with the contacts controlled by an arm attached to the counter-weight. When the engine is stopped (no air flow), vane/counter-weight is in the "home" position and the contacts are held open (pump off). Key "on" powers the switch. Starter running turns engine, creates suction/air flow through the AFM, rotates the vane/counterweight which swings the arm away from the switch, allowing the contacts to close which turns on the fuel pump.

Sooo, you shouldn't hear the fuel pump running just by turning the key to "On". The pump should only run with the starter engaged and/or engine running.

Edited February 6, 201213 yr by Willoughby Z

Thanks for the info guys. I had my AFM apart today and noticed the arm did not engage the fuel pump shut off switch unless it was motivated just a hair. I know it needs adjusting but I did not want to mess with it as I was not sure at the time if my AFM was my problem. Needing to drive my car today I re-instated the jumpers that were in place and with no fuss it started right up and ran smooth all day. The jumper are as follows. The blue w/white wire at the fuse box is connected to the blue w/red wire at the ignition switch. The white w/black wire at the fuse box is connected to the black w/white wire at the ignition column. I may try to tweak the AFM some more next weekend but for now I am tackling a radio install so I can have some tunes while driving around. I will post my results after I work on the AFM.

If you don't have this, it will help with both issues (radio and fuel pump).

Fuel Injection "bible"

http://www.4moores.com/280z/files/280zfuelinjectionbook.pdf

I have it saved and have already utilized it. Unfortunately for alot of issues it refers you back to the FSM which I have already too. I got my radio install about 50% but have discovered through much trial and error I have a new defective speaker. Appearantly the voice coil inside is grounding to the case thus grounding the speaker out. I am probably going to leave the AFM alone for now. I dont want to crack back open since I sealed it up earlier today. I am still curious as to what the jumper wires are actually bypassing.