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The mkiv Supra Owners Club

Fuel pump and 12v relay mod


berg

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Ive fitted a wolbro 485 and have done the fuel pump mod using a relay

Everything is wired as per the diagram everyone posts on here

 

Strange thing is i can hear the pump whining constantly with just the ignition on

 

Im yet to test it with a meter, that will be tomorrows job But i was under the impression that the pump wont be on until you crank the engine?

 

Ive triple checked wiring and everything matches, ive disconnected the relay and tried again and pump is dead as expected as they wont run with the stock 9v

 

I also fitted an AEM FPR at the same time which with ignition on is reading 40psi (engine off), i werent sure if the pump would keep running until a certain pressure was reached but ive adjusted the pressure and its still the same (40-42psi for the supra so im told)

 

Anyone able to shed any light?

Edited by berg (see edit history)
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Doing the 12v mod using the relay it should work as it did before, only when the pump is running it will see constant 12v not the variable 9v-12v

 

Normally the pump will prime for a couple seconds then go off until engine is started

 

But now it seems to always be on

 

You are right about the pressure relief valve

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You should just here it prime for a second or 2 and then silence with or without the 12v relay mod.

 

The 12v relay mod just bypasses the pump control module so the pump is running 12v at low speeds and low revs.

 

I've done the 12v mod as I felt its worth doing due to bigger injectors ect, but the pump wont sound any different.

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Yep i know that, but with this done mine is on constantly with just the ignition on

 

Im starting to think i have an issue somewhere else now as the relay/wiring is spot on

 

The whole fuel system is new aswell as the link ecu thats just been fitted

 

 

 

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Tested with a multimeter today

 

With ignition on i am seeing 11.7v at both the pump ecu and the pump itself

 

Could this be anything to do with the new link ecu and the fuel pump ecu configuration?

 

Link ecu is straight out of the box, nothing setup yet as i havent got to that part yet

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If you are running a link you need to $#@! the pump ecu off and replace with a relay. I use one of the pump ECU control wires as a ground switch from the ecu.

 

Which Link ECU are you running or do you have the plug in?

 

I have the G4+ plugin

 

This is how its wired

 

mrs3lc.jpg

 

Ive popped the stock ecu back in and now the solid blue wire (blue&orange in my case) shows 12v which i guess is for the ecu feed and the output to pump shows 0v

 

But the pump doesnt prime, fuel pressure remains at 0

 

Surely it should run the pump for a few seconds and then go off?

Edited by berg (see edit history)
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Ive got as far as map sensor calibration and throttle position

 

Thats all the link instructions say to do pre first startup

 

fuel pump configuration i havent looked at and wouldnt know how to, I wanted to at least have it running and give it a full check before it goes to the mappers but thats looking unlikely now

 

Trying to do the PCLink stuff but after the pump is running on ignition for about 1 minute it starts making a very loud buzzing noise which doesnt sound too good, if i switch off and back on its ok for another minute then does it again

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