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Discussion Starter · #1 · (Edited)
Hello all
Ive done the fuel pump mod with a relay
For now i have connected my power #87, to the white plug in the spare wheel well, but i have a little current loss from the white plug to the plug on the hanger, have you guys been able to fit a 10gauge wire to the plug on the hanger/pump?
Or have you just been fine as is? The OE wire from plug to hanger is like gauge 13 or 15?
 

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I ran my 12v 10ga wire thru the hanger and directly to the pump, and I still lose .5v. I get 13.5v vs 14.0v at the battery. You're always going to lose a little. You are using the factory fuel pump ECU for the signal, correct?

Al
 

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Discussion Starter · #4 ·
Just what I wanted to hear!
How did you manage to get it thru the hanger?
Do you maybe have picture?
Yes fuel pump ecu for signal
 

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Discussion Starter · #6 ·
Perfect! Drilled hole using some sort of a plastic ''grommet''/bushing? Not sure the correct word.
 

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It's a bulkhead, I think I got it from Summit. Drilling thru the hanger is no picnic, and you have to get the location perfect or you can drill thru the spot welds for the bracket and ruin the strength.

Al
 

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Wow, 2v loss was thru the factory connector and wiring to the pump?

One guy on here claimed to still use the 9v/12v modes with an aftermarket pump. I may eventually look into that as I think my fuel is getting hot with full 12v, there is pressure in the tank after a drive sometimes.

Al
 

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One guy on here claimed to still use the 9v/12v modes with an aftermarket pump. I may eventually look into that as I think my fuel is getting hot with full 12v, there is pressure in the tank after a drive sometimes.

Al
That would be me. Every car (TT) I tune, I PWM the fuel pump ecu for 9/12v operation. I don't know why you wouldn't. It drops the fuel temperature, lowers the noise, and also lowers the amperage draw from the alternator.

Drop in a simple Walbro 274 and it will make 600+whp on e85. Stage 2 of them and you have a 1200whp setup. Pretty simple.

If you are worried about the oem wiring, you could depin the factory wire and replace it with TXL. Although I have not found this necessary, it is a nice upgrade.
 

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But you're handling this with a standalone, correct?

Not sure how I could wire that in since I have 12v directly from the battery that has to go thru a relay to the pump, and the relay is triggered by the FP ECU 9v/12v wire. I suppose instead of running that wire to the pump, it could be the 12v into the FP ECU?

My DW400 pump is whisper quiet, but I have noticed I have had pressure built up in the tank on occasion after a drive.

Al
 

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But you're handling this with a standalone, correct?

Not sure how I could wire that in since I have 12v directly from the battery that has to go thru a relay to the pump, and the relay is triggered by the FP ECU 9v/12v wire. I suppose instead of running that wire to the pump, it could be the 12v into the FP ECU?

My DW400 pump is whisper quiet, but I have noticed I have had pressure built up in the tank on occasion after a drive.

Al
Correct. Any good standalone ecu can control the fuel pump ecu (Motec, ProEFI, Syvecs etc). Are you on the factory ecu?
 

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Yes, I am on factory ECU.

Al
I assume you are bypassing the fuel pump ecu to try and gain an extra volt for the fuel pump? Is it really worth it?

I don't have any experience with DW400 pumps, however 2 Walbro e84 pumps will make 1200whp easily with the fuel pump ecu still functional.
 

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No, I am using the FP ECU, I never said I wasn't. The 12v blue wire from the FP ECU triggers the relay and sends the 12V from the battery the rest of the way to the fuel pump. I get 13.5v at the pump vs 14.0 at the battery.

Al
 

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No, I am using the FP ECU, I never said I wasn't. The 12v blue wire from the FP ECU triggers the relay and sends the 12V from the battery the rest of the way to the fuel pump. I get 13.5v at the pump vs 14.0 at the battery.

Al

That is my whole point. Why are you adding an external relay for the primary pump, essentially eliminating the fuel pump ecu control (9v/12v)?
 

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The consensus on here has always been that the factory wiring is too small, and there are voltage gains to be had with upgrading the wiring, hence the 12v mod. Though the mod has gotten safer over the years by using the FP ECU to trigger the relay instead of a random accessory.

I decided to go with one pump, I need all that pump can put out. The DW400 is equivalent to a Hellcat pump, but draws a little less amps.

Al
 
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