Hi guys, recently, my 300zx has been having issues starting. I disable the immobiliser, turn the car to reds, and instead of hearing the fuel pump prime, i just hear 2 clicks, sort of like a relay. But it sounds as if its coming from the fuel pump area, not the FPCU location. I have swapped both the fuel pump, and that didn't fix it. So I swapped the FPCU and that fixed it for 2 days, now its doing it again Going to bypass the fpcu tomorrow, but any other suggestions as to what it could be? Cheers, Logan
Bypassed fpcu. Still no go, any other ideas? Fuel pump has ground, and has a wire with 7.5v, one with 0.05v and one with 11.8v. Does this sound right?1
It's very interesting that after you changed out the fpcu then it worked. Almost like you disturbed a wire/connector. The fuel pump could be cactus and just a fluke that it got going afterwards. The click you hear could be a relay. You would think if you had 12 volt - and 12 volt + to the fuel pump the pump should just run. The interesting part is the voltage on the other wires at the same time. A wiring diagram would be helpful to tell you exactly where the power should be. I would just run a 12 - and 12 + straight from a battery to the fuel pump and then if the fuel pump is no go it's a no brainer. Cheers Dave
Update... So, one of the wires at the fuel pump (Thick orange) was not getting any power. This is connected to the FPCU (no power there), and then to the fuel pump relay. The relay did not have a ground for some reason, so i wired it directly to a bolt to ground it. The orange wire at the relay now has power, but not at the FPCU -_- Going to trace the wire between the relay and the FPCU tomorrow to make sure there is nothing disturbing it. Voltage at the battery was a bit low due to excessive cranking. How do I test the fuel pressure if I can't get it pumping?
