No power to fuel pump?

[nelsonmxmarc]

I butchered quite a few wires this winter in an attempt to save weight, however at some point along the way i may have upset the fuel pump wiring harness.

I have traced ALL wires from the pump, to the voltage regulator, to the relay and to the ECU. ALL are intact.

So i haven't physically removed any wiring from this unit - question is, why does my fuel pump not turn?


I've pulled it out and tested it with a 12v source - works.

I've traced all the wires, they're still there.

Engine is out, so all engine grounds (alternator, wiring looms etc) are NOT grounded, possible issue?

There is one catch;





12v live wire on ign. from this box; what is this box, and where does this wire normally go?

There are no signs of a black/brown spotted wire in the trunk or anywhere in the loom so as far as i can tell it doesn't belong back there.


Also, i believe my easiest route is to wire in a direct 12v feed with relay from the battery as it's already relocated. It would certainly save time... I'm just unsure about wiring in the relay.

[NismoS-tune]

Easiest thing in my opinion when you can't figure out the OEM relay is to take the current pump power wire and have that go to a new relay coil which you'd just use to control a larger cable from your battery. If you're not getting 12V on the positive of the current pump wires, you could have a buggered relay but I'd guess you could have a blown fuse? I do a lot of electrical so the more info you have the better for me

A bad ground (negative) could stop the pump from running if you have 12V positive.

[rb26addict]

i had a similar problem with my old stock pump, i switched the relay with ac one i think it was and it worked fine for a couple of days then my fuel pump fully died thanks to a blown fuse and lastly the fuel pump took its last sip of fuel in a parking lot ...... thing is though it would work fine on and off when i hooked it up directly to a 12 volt source .....so dont rule that out cause my stock fuel pump would work for like 2 min then die for like 5 then work again...... Lastly get a multimeter to check it voltage is going to the fuel pump harness

[nelsonmxmarc]

Thanks guys!
Rb26addict, i have a multimeter and have checked all over for a 12v source in the trunk on the fuel pump line in, nothing. I haven't ruled out the relay, but i'd find it quite strange having not touched anything since it went into storage..

Franc, exactly what i was thinking. i'm going to run to our local electronics supplier here and pick up a 12v 30 amp (onboard) relay, or just wire an inline 30 amp fuse with a 12v relay. I'll grab the signal on through the ecu signal wires, and wire in the 12v through to the pump, and ground the pump to the battery..
Probably the best bet, otherwise i am STUMPED lol

And as far as i know, relay is fine. Fuse is not blown. Grounds were tampered but have all been replaced and are 'well grounded'..

So yea, seems its the 12v inline that's the issue, and as far as i can tell, besides the defrost and rear amplifier, the black and brown spotted wire above is the only 12v out that has no home, and completely baffles me.. lol.

[DreadedFist]

Stripping wires to save weight... Is this a full on race car? That's pretty hardcore.

[nelsonmxmarc]

Stripping wires to save weight... Is this a full on race car? That's pretty hardcore.

Lol, no. But i have a goal of breaking 1100 kg, and in my trance i managed to tear out a lot of useless, and perhaps useful junk.

I may convert it to a full track car, and retain the QC plates for regi in the future, but for now, it will be my summer love.

I have to add that they were rather useless, however; door sensor/belt sensor/rear amplifier speaker wires/hicas and door speaker wires.




..And maybe something fuel pump related...

[DreadedFist]

..And maybe something fuel pump related...

lol damn.

[NismoS-tune]

Lmao, what you should have done is strip the car of electrical while it ran :P so you'd know if something you needed was removed haha, jj.

That's lightweight though! You should get a race cell unless you already did. The stock fuel tank is big and heavy.

Lol, no. But i have a goal of breaking 1100 kg, and in my trance i managed to tear out a lot of useless, and perhaps useful junk.

I may convert it to a full track car, and retain the QC plates for regi in the future, but for now, it will be my summer love.

I have to add that they were rather useless, however; door sensor/belt sensor/rear amplifier speaker wires/hicas and door speaker wires.




..And maybe something fuel pump related...

[cschepp]

Isn't the gts one heavier since it is steel? I went from a gts to a gtr one, a huge difference