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1994 Subaru WRX fuel pump fault. Anyone had problems?


Seedy Al

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Hey guys

Currently working on a 1994 WRX. Wish I fucken wasnt but you cant control what shit people bring into your workshop

Anyway, the fuel pump doesnt go. So far have tested the pump, and that works fine.

have checked the relay, and the relay works fine. I have power to the side of the relay that runs the pump, and I have power to the side that turns it on.

So i am getting no signal to the earth side of the relay to engage it.

they said they just drove it in there drive, and next day it would start.

I have also checked the spark and thats fine, as I thought it might be the crank angle sensor or something, though clearly not.

Anyone had any problems with these before?

i cant find a decent pinout for this sack, so I havnt been able to trace the signal wire as I cant see it going into the ECU.

I have also tried a different Airflow meter in case that was faulty and roll over circuit was fucked.

So i just dont know. Suggestions :D

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Shagged ECU would be the only thing i could think of. Tried hotwiring the relay to run the pump and then starting it?

currently been looking into this at the moment,

tried it with the relay i thought it was and got nothing, so tried the other relay and got nothing.

now I have confused my self on which relay is for the fuel pump.

I know the brown one is for ecu (or so I have read)

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OMG that cat^ is moving in time with the tune on the radio now.

So you've got 12v signal to the relay from the ecu and 12v from the ignition circuit but the relay isn't operating?

Sounds like no earth for the relay as you said. Try running a wire from the other side of the coil on the relay to the car's chassis

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When I did alarms this was very common as it seemed when a car doesnt go they blamed the alarm but was faulty fuel pumps.

Actually does the car have an alarm? Check the fuel cut (if it has one) cos this may have a dry solder or a funky immob relay.

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I've struck this before on a subbie, same fault too!! Have you checked the earth on the fuel pump in the multi plug?? You say the fuel pump works which you'd have checked out of the tank? So no power at the plug to the pump and the relay? I'd be checking you're getting 5v feed from the computer to htings like the AFM and earth side of the fuel pump multi plug to be on the safe side. Then all plugs on the relays and the e.c.u for corrosion

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I assume the fuel pump relay is operated via earth within the ECU?

And if so then I will be chasing down the wries from the pump back.

Also... Yeah it has remains of an old alarm under the dash, and they have just installed a stearo, so thats the first place I tried to check, however thre are fucken cut wires and shit everywhere!

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FUCK I LOVE YOU GUYS!!!!!!!!!!!!

Was totally the plug under the rear seat.

And I looked at that to start with and thought it was a bit shit. Should have tested that instead of jumping in at the deep end.

So as the old saying goes, its always something simple.

Time to cut the whole plug out and solder the lot together, fuck em.

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one of those magic ones that have a wand and a signal generator thing and you wave it over the loom to trace the wire the signal generator is connected to

and it goes "weee-wooooo-weeee-woooo" when it is close to the wire / ask sparky

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