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The mkiv Supra Owners Club

12v mod with relay.


Guest Poopra1

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To run a walbro 400 and above you need to do this mod, the pump will not run on the low voltage 9v off boost voltage the fuel pump ecu gives out , this mod is to give you a 12v feed constant but to still give you the safety features of the stock fuel ecu ie fuel cut in the event of a crash!!!!

 

If you dont fit the relay and wire directly to the 12v you will always have the fuel pump running as soon as you switch the ignition

 

Its your call pyro

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I get the part that you need to get a wire directly from the battery to the relay so the pump gets the 12V all the time when the car is running but what I was after is if this 12V mod is necessary http://mkiv.com/techarticles/12v_mod/12v_mod.htm since the relay will trigger itself on voltage between 1,6V - 12V so from what I understand you dont need to do the 12V mod to the ECU and just take the cabel that feeds the pump from the ECU and run it by the relay that triggers the 12V from the battery, the original fuelpump cabel gives out 9-12V without the mod done but that shouldnt bother the relay that feeds the pump with 12V all the time since the relay will trigger itself on voltage between 1,6V - 12V.

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  • 10 months later...

Good evening.

I have just installed a DW200 fuel pump on my 1998 Vvti Supra TT. (the car start fine with this new pump, not tested yet in "hard condition" , just one start and it work)

 

I have checked all "12V mod fuel pump" here and on supraforums.com.au, and i wanted to do the mod on my car, but i don't find the Fuel Pump ECU on my Vvti TT !!

 

can someone tell me where it's located ? (or if there is any fuel pump ECU on a Vvti TT ?)

 

in the trunk, where it's supposed to be, there is just the trunk light and a red electric stuff, but nothing to do with the pump (no big wire )

 

can someone help me? does this mod isn't needed on a Vvti TT ?

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  • 3 months later...

I have the walbro 450LPH pump installed and working but I get that strange ticking from the relay now and then as for some others here. I run an new cabel from the battery to the relay and new cabels to the fuel pump. Is this the right way to connect the "trigger" cabel to the fuel ecu harness? It is spliced in to the RED/BLUE wire. Or should I do something else also to get rid of the strange on/off ticking of the relay?

 

IMG_20170618_205135.jpg

Edited by EleCtRoN (see edit history)
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I have the walbro 450LPH pump installed and working but I get that strange ticking from the relay now and then as for some others here. I run an new cabel from the battery to the relay and new cabels to the fuel pump. Is this the right way to connect the "trigger" cabel to the fuel ecu harness? It is spliced in to the RED/BLUE wire. Or should I do something else also to get rid of the strange on/off ticking of the relay?

 

[ATTACH=CONFIG]219675[/ATTACH]

 

You should get a correct drop out voltage relay

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Ok

Check that you have the 9v supply from the fuel pump ecu to the coil of the relay and the 12v to the ecu through the contacts to the pump.

Its not uncommon for the fuel pump ecu to fail if thats what you have set up then youneed to monitor the voltages to the coil and see if your getting a drop in voltage. That being said if you have a bad connection this would also cause you problems. Also check that earth you have done not sure that insulation sound deadening conducts electricity ;)

Edited by mellonman (see edit history)
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I have it set up like this now, any thoughts?

I3tbC62.jpg

The chassi ground is under the same bolt that holds the fuel ecu but I will check it.

 

Should I run a wire between the factory fuel ecu 12V (blue wire) to the new wire that goes from the relay pin 30 to the new fuel pump?

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