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R33 Fuel Pump Relay Issues

alexboland
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alexboland Explorer

alexboland

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Posted (edited)

Hey guys

Not sure if this is the right forum but i couldnt see electricals anywhere.

The problem is the earth wire at the relay isnt getting current. All the other wires are getting current. The other day the earth wire was getting a low amount but the car wouldnt start.i did manage to start it by grounding with a screwdriver. But now that wont work as the earth wire isnt getting any current at all. The fuse is good and i swapped the relay but it still wouldnt start. When i turn the key in the ignition the fuel pump continues to run until i take the key out. Its running but i dont think theres any pressure to deliver fuel to the engine. The fuel pump is fine its just the relay. Any help would be much appreciated.

Edited by alexboland
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https://www.sau.com.au/forums/topic/463017-r33-fuel-pump-relay-issues/
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jiffo Mentor

jiffo

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Posted

I think you should check out the factory wiring first.

The relay has 12V+ constant feed once the IGN is switched on and the grounding of pin 18 at the ecu is what controls the pump.

The high/low speed side of the system works the negative side of the pump.

Full speed has the negative direct to ground.

Low speed has the negative to ground via a resistor.

If you want the pump to run at full speed all the time you simply ground the negative and job done.

If your pump continues to run after the normal 5 second time out, then the wire from Pin18 to the relay could be rubbed through somewhere to ground.

OR the fuel pump control section of the ecu may be faulty.

OR the relay may have melted its contacts together.

All easy stuff to check.

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