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Spencer
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823 Posts
Discussion Starter #1
I am wiring up my relays for my dual walbros and have a question. For the trigger source on the relay can I use any wire that is a postive hot lead when turn the key to the ON position. I think I found that wire, when the key is in the ACC position the pumps are not triggered, only when you go turn the key on click further to the ON position. That means anytime I turn the key to the ON position the pumps will be running, is this correct? Is this how the factory pump is? I found a trigger source wire that goes into the fuel computer , its a blue orange line wire.
 

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Hardtopper Once Again!
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1,709 Posts
They should be kicking on when in the ACC position, if they aren't you wired something wrong.
 

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Supratruck Pilot
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882 Posts
That is not how your factory pump is and it would be very dangerous to do it that way. If you were to have an accident, or worse a fiery accident, the pump would continue to run and feed the fire with fuel. Find whatever is triggering your pump now and use that to trigger your relay.
 

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Registered
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If you've ran new wires to power the pumps, then use the factory wires that use to run the stock pump to trigger the relay. I don't do it like that though. Factory wiring runs my two walbros.
 

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Spencer
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Discussion Starter #5
I ran all new wiring for both pumps, I am not using the factory harness/connector, I disconnected so its dead.

So I should just use the factory power wire (Blue wire on the factory pump+) to trigger the relay. Thats what I thought, and wired it that way temporarly and checked the voltage. With the key on the ACC or ON position there was not 12volts going to the factory pump+ wire.

So the pumps should not be running with the key in the ACC or ON position correct? The pumps will start only when I turn the key all the way to START.
 

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Making a ComeBack!
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1,058 Posts
So the pumps should not be running with the key in the ACC or ON position correct? The pumps will start only when I turn the key all the way to START.[/QUOTE]

If the pumps don't come on, when the car is on ACC or in the ON position then how will it start, it needs to be that way so the fuel will start to flow, Don’t you need to purge it 1st bfore it will even turn over. :dunno: atleast that what I thought, Just run a new wire direct from the battery with a FUSE if you are worried about a fire then run a fuse (back to the relay), it will blow and CUT power to the pumps.... that's the way I know to run it. (Even in that Titan video they turn on the car ACC/ON position to purge it), the pumps come on then they start the car...
 

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Supratruck Pilot
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882 Posts
If the pumps don't come on, when the car is on ACC or in the ON position then how will it start, it needs to be that way so the fuel will start to flow, Don’t you need to purge it 1st bfore it will even turn over. :dunno: atleast that what I thought,
The ecu sends a signal to the fuel pump when the engine is cranking. Once the engine is running it continues to send a signal until the engine dies.
 

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Making a ComeBack!
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DLC said:
The ecu sends a signal to the fuel pump when the engine is cranking. Once the engine is running it continues to send a signal until the engine dies.
Yeah but you need that added protection this is why I say run a new 12volt source with a fuse as a security measure (with a thicker gauge wire). this is what i have 1. 12volt source to the relay (directly from Battery with a 30amp fuse), 2. Trigger solid blue wire 3. solid blue wire from pumps and 4. ground to the relay... I think doing it this way is better ATleast you get to chk for leaks on the fuel system before starting the car which can prove to be more dangerous...
 

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The need for speed
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I have done the 12volt mod for mine. I have one pump wired to the factory wiring, and the other pump going to a separate relay triggered by a fuel pump wire going to the fuse box in the engine bay. Both pumps are running whenever the car is in the "on" position. This isn't very safe, so I wouldn't recommend wiring it this way.

Typically, when you turn a car to the "on" position it should "prime" the fuel pumps, usually by running the pumps for a few seconds to build up fuel pressure. Then they shut off - when you turn the car over the pumps turn on again and remain running as long as the engine is running.

I'm not exactly sure how the pump operates on a stock supra...

-mike
 

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Spencer
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823 Posts
Discussion Starter #12
whizky said:
I think doing it this way is better ATleast you get to chk for leaks on the fuel system before starting the car which can prove to be more dangerous...
You can always wire the trigger to a constant power and check for leaks, then
wire the trigger up correctly to the pump+. Thats what I will be doing. :bigthumb:
 
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