TwinTurbo.NET: Nissan 300ZX forum - Fuel pump stays on without key..or fpcu
People Seeking Info
 
   


     
Subject Fuel pump stays on without key..or fpcu
     
Posted by pandamanz32 on August 09, 2018 at 11:24 PM
  This message has been viewed 613 times.
     
     
Message Wile doing wiring on my vert, for my widebands, I noticed a strange wire that was jammed in with a fuse in the fuse panel. I was concerned about what kind of bad wiring the previous owner may have done so I decided to investigate. After tracing the wires I found my fuel pump relay is being bypassed with a random 30a relay.

The black and purple wire (ecu pin 18, fuel pump) has been cut from the connector and spliced into this other relay which is getting power from a wire stuffed in with the 15a EPS/HICAS fuse (for ignition power I assume). I did locate the other part of the original black and purple wire in the harness. When connected, the relay gets triggered, the fuel pump gets power and turns on without the keys in.

I bypassed the fpcu to test if maybe it was malfunctioning and causing a short to ground. However fuel pump was still running. So I unplugged the fpcu and it continued to be on. I looked up the wiring diagram and physically traced the orange power wire from the connector at the fuel pump, to the connector by the fuse box. I checked the orange wire at the air regulator and didn't get anything. I also did a continuity check from the ecu to the relay (cut side) and got .7 ohms. Disconnected the ecu and now no power to the fuel pump unless the purple and black wire gets ground.

Does this mean my ecu is bad or is there something I haven't thought of yet? Another problem this car has been having is that it seams to never want to have correct timing. I've torn this engine apart repetitively to make sure all the timing makes were aligned correctly and replaced the car, ptu, and ign relay so this kind of makes sense to me.

____________________________________________________

Function + Form = Z

     
Follow Ups  
     
Post a
Followup

You cannot reply to this message because you are not logged in.