# Where are the fuel pump control module and sub fuel pump relay located?



## GT-R Sweden (Sep 23, 2014)

Im planning to hardwire my pumps, but I'm not sure where the fuel pump control module and sub fuel pump relay are located?

Anyone here who can tell me this? 

Here's what I gonna do:


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## Ricky Elder (Sep 11, 2013)

Hello,

The main fuel pump control unit is located under the right hand rear passenger side trim panel.

The sub fuel pump relay is located in the boot behind the right hand side trim panel.

When you say hardwire the pumps, are you planning to remove the fuel pump control unit and sub fuel pump relay completely? Or are you just uprating the wiring between them and the pumps?

Cheers Ricky


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## GT-R Sweden (Sep 23, 2014)

Ricky Elder said:


> Hello,
> 
> The main fuel pump control unit is located under the right hand rear passenger side trim panel.
> 
> ...


Great thanks!

Basically I'm providing a direct 14+v source straight from the battery to the power input terminal (OEM fuel controller) via an extra relay.
Output power terminal (wire going to primary fuel pump) will also be "beefed up" by wiring it with thicker gauge wire, since more power is now available from the fuel controller.

Also the sub fuel pump will be feeded with a good 14v via an extra relay.

All the other hardwire methods just use the OEM output power terminal to trigger a relay that then provides a solid 14v from battery, but this method is still considered "bypassing" the controller since all the logic is taken out of the equation.
It will also generate a fault code, P1220.


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## Hugh Keir (Jul 25, 2001)

Do you know what the function of the OEM fuel controller is? 

Does the fuel pump current & voltage supply change with load?

Thanks

Hugh


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## GT-R Sweden (Sep 23, 2014)

Hugh Keir said:


> Do you know what the function of the OEM fuel controller is?
> 
> Does the fuel pump current & voltage supply change with load?
> 
> ...


The primary pump has 3 voltage steps which is controlled by the pump control module.
The secondary pump will only kick in during WOT or heavy part throttle and is only using a fixed voltage, supplied from the sub fuel pump relay.


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## Ricky Elder (Sep 11, 2013)

Yes, the primary controller will duty cycle the main pump in 3 steps with the sub pump activated on the last step.

This is load dependant and signalled to the controller by the ecu.

If you remove this controller, then you need to modify the fuel pressure control system accordingly and make sure the control strategy in the ecu is correct.

Cheers Ricky


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## GT-R Sweden (Sep 23, 2014)

I made the modification on the pump harness yesterday, but now I get a code, P0627 Fuel Pump 'A' Control Circuit/Open and the car goes into limpmode @ ~5800rpm...

I'll let my tuner turn it off in the software and see what happens.
After that I'll Vbox the car and see if the 14 volts feeding made any improvements.

Unfortunately I think my injectors (id1000) are maxed out now in the cold weather here in Sweden.
I'll maybe change to a set of id1300 instead.
What do you say about them? I'm FBO with e85.


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## mindlessoath (Nov 30, 2007)

DIY - How to hardwire your fuel pumps and keep all controller functionality - DIY Guides - Nissan GT-R Heritage

not sure if this helps, good luck!


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## Ricky Elder (Sep 11, 2013)

If you wire out the condenser in the oem harness you will get the fault code above.

You need to refer to the wiring diagram.

Cheers Ricky


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