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Fuel Pump Wiring

johnnyt

By johnnyt,
in Engines & Forced Induction

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johnnyt Rising Star

johnnyt

Posted
Posted

Gday guys

ive searched and found some good info on this but im still a lil stumped.

ok.. r32 gtr just swapped my built 26 back into the car, been off the road for about a year.. running a new fuel system which has a external pump surge and new lines all the way to the front of the car. set up a new relay which has a direct feed from + and - all the way to the battery. trying to splice the trigger i thought id check make sure its getting power at ignition... fail. no power from the yellow and black wire when ignition is turned on.( which im 90% sure is the power feed to the standard pump) checked the green relay near the boot lock and found its receiving power at two pins when ignition is on. obviously the relay is switched by earthing from the ecu.which i think isnt happening. so far the car has the standard ecu in but i will be swapping it out for the powerfc that is sitting on my desk this afternoon to see if this fixes it. (which i highly doubt it will) if not i was thinking of pulling one of the power feeds from the fuel pump relay to trigger my relay setup at ignition, but obvioulsly it wont prime for a few seconds and stop at ignition it will just run constant once ignition is on yeah?

so

dash lights up at ignition

cant hardwire the pump and try start engine yet as its not ready. hopefully this issue isnt affecting other areas.

all plugs seem plugged in, there is a thick black wire from the + battery harness which i think may be a negative.. not sure.. can anyone help with that one.

i have changed the + side of the battery harness from another gtr,same year model.

i have changed the fuel relay in the boot for the aircon one to test, but still no go.

do all the cas,coils,injecter harness need to be plugged in for the fuel circuit to work?

what bloody fuse is for this ecu/fuel circuit(its in bloody japanese)

has anyone had this problem before?

cheers in advance fellas

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BH_SLO32 Proficient

BH_SLO32

Posted
Posted

If you are getting power to the standard fuel pump relay it implies the fuse is ok. Next thing is to check the trigger side of the relay is working (appears not to be working at present). With the computer unplugged and the ignition switched on, measure the voltage at pin 18 (Fuel pump relay control - black wire with pink/purple trace). You should see batt voltage. If there is no voltage at this terminal it implies a break in the wire between the relay and the ECU.

If the voltage is ok, switch everything off and plug the ECU back in. Switch the ignition on and measure the voltage again. This time you should see approx 0V (whilst the ECU is priming the pump - first 5 seconds or so). Best to get someone to measure the voltage when you switch the key on. This will tell you if the ECU is switching the relay on when it should.

Cheers

johnnyt Rising Star

johnnyt

Posted
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Posted

Cheers Ben, will give that a go tonight.

could there be any plugs in the bay that ive missed stopping the ecu giving this earth?

worse case scenario.. i cant get the ecu to ground the pin.. can i use the ignition feed from the standard fuel pump relay as my trigger for my big sx pump and the standard intank pump?

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