Fuel pump relay control wire

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hemicat
Posts: 167
Joined: Fri Nov 21, 2008 9:24 pm
Location: Brooksville,FL

Fuel pump relay control wire

Post by hemicat » Tue Oct 18, 2016 11:31 am

I just started a 95 ej22 swap and got the harness trimmed. Somewhere in the process I cut out the fuel pump relay and got it connected back up thanks to the busaru videos and ecm pin out diagram. The only thing I'm missing is the violet wire on pin 84 that goes to the pump relay, but in one of the engine connectors it also contains the same wire and I have no clue what it goes to and if I need to just put all 3 wires together or if I even need to connect it. It is on the removed harness side of the connector. Other than that I think I'm ready to loom it and get it connected. I have checked every wiring diagram that I could find and it only showed that wire going from the ecm to the fuel pump relay. Thanks in advance for the help.

maurice
Posts: 11
Joined: Sun Apr 03, 2016 12:49 pm

Re: Fuel pump relay control wire

Post by maurice » Wed Oct 19, 2016 1:40 am

Some of the wires branch off into the engine, but are spliced off into other parts of the car. I know several of mine do, and have done it on an obd2 car as well.

Is the wire you're looking for a power or ground wire from the ecu?

Your options are to trace the correct wire from the pin, and splice it in with wherever it goes.
Or wire the relay to turn on with ignition on (if it's a power wire). I've bypassed the fuel pump on both of my harnesses, and just kept it as ignition on. You can also simply take out the relay and jump the two large wires together.

Someone please chime in if the ecu controls the fuel pump off for any safety reason (out of oil, failing sensors etc.).

There aren't too many duplicate colored wires I've run across. Besides ground and power, most everything is colored specifically from one origin - even if it ends up at two destinations.

hemicat
Posts: 167
Joined: Fri Nov 21, 2008 9:24 pm
Location: Brooksville,FL

Re: Fuel pump relay control wire

Post by hemicat » Fri Dec 09, 2016 10:21 am

Got everything installed and hooked up with just the wire from ecm to relay. Ecm controls ground to relay, plugged in test connector and pump cycled. Figured the worst that would happen was it wouldn't start. Well it worked first try and have put about 500 miles on it since with no problems with fuel. Not liking my rear radiator setup but that's another discussion... Thanks for the reply and at least now we know.

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