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So after running my DW300 in-tank pumps for a year or so, I started tweaking pump voltage through the FPCM and quickly fried the FPCM itself. I have read elsewhere that the OEM module also drives the second pump at a lower voltage, as the FPCM itself is ultimately limited in the voltage (and amperes) it can handle over time. Like any circuit, more amps over time will shorten its life and it reduces your total potential fuel flow.
One option, to fully maximize the DW300 in-tank pumps, is to split the current between the FPCM itself and a second driver - enter the Vaporworx Ally controller. It's pretty slick, as it emulates the OEM FPCM signal for pump pulse-width modulation to drive the second pump as if both were still controlled by the OEM module, but it can handle 40 amps itself. So you're effectively cutting the current draw through the OEM module by half (as it's only driving one of the in-tank pumps, and the Vaporworx module carries the second pump).
In other words, you can think of the Vaporworx module as a stand-alone relay that mirrors the signal from the FPCM, but Carl (of Vaporworx) has built them to handle way more current than any in-tank pump can draw, and in this setup the life expectancy of his modules is 90+ thousand miles give or take.
Running the wires in a suitable manner is the hardest part of this install, but the whole think took me about 5 hours due to cutting, splicing and running conduit under the car and fishing it up to the fuel hat (see below).
Vaporworx Ally controller (website)
The controller is simple: +12V and Neg to the battery terminals, +12 and Neg to either of the in-tank pumps, pinning them into the connector at the top of the fuel hat, and a signal wire either of the Neg pump wires (for the PWM signal). There is an option to wire in a BAP also, but it's probably not needed for our cars in this scenario.
![Font Circuit component Electronics accessory Cable Audio equipment]()
Easy option: run your +/- wires to the pump connector along the side of the trunk under the rear seats to your cut-out (because you have cut out an access panel by now surely). But your wires will be exposed under the rear seat and where they drop down to the fuel hat, so I don't recommend this.
Hard option: run your wires through the grommet in the battery compartment, which drops down to the passenger rear quarter panel behind the rear subframe. From here, you can snake them over the subframe to the gas tank and fish them up to the fuel hat and pump connector. This takes a while, but is easily done with a flashlight, a few jack stands and some patience.
I just punched a hole in the grommet (it's very thin, but pliable) and taped the Pos/Neg and signal wires together. Push them through and find them by pulling back the rear wheel well cover. Pull out about 6 feet of wire, then wrap them in sheathing.
![Hood Automotive design Automotive exterior Motor vehicle Auto part]()
It was hard to get photos here, but using the OEM harnesses under the car you can fish them over the rear suspension and rear subframe, using zip ties as needed, and then work the wires to the tank. I dropped a spare wire from the top of the tank down, taped it to the bundled wires and then pulled it back up to the fuel hat:
![Hood Automotive tire Automotive lighting Bumper Motor vehicle]()
Now you need to strip the three wires and install the provided terminals with a good crimp. I de-pinned one channel (a gray and red wire), and replaced them with the red/black (Pos/Neg) wires I just pulled up. Note: the two sets of wires that control the pumps are Tee'd off from a single Pos/Neg feed from the FPCM, so it doesn't matter which side you use. The third, gray wire is the PWM signal and can be connected to the gray (neg) wire you just de-pinned, as it is still receiving the signal from the FPCM; I used a spare GT280 connector I had laying around but it could be crimped, soldered or whatever.
The remaining red +12V wire needs to be terminated safely to avoid shorting - I used a few layers of heat-shrink to cover the exposed terminal, while allowing me to re-install it down the roead if needed.
![Hood Car Vehicle Motor vehicle Automotive fuel system]()
Then connect the Vaporworx controller using the supplied terminals and the wires you just ran:
+/- to one of the in-tank pumps (red/black)
+ to the Positive Battery terminal (orange, fused)
Gray PWM signal to the de-pinned gray wire from the fuel pump connector (at the fuel hat)
Neg (black) to the battery ground into the chassis just to the rear of the battery
![Vehicle Automotive tire Hood Motor vehicle Automotive lighting]()
Car starts right up and functions normally with both pumps running, however the total current draw is now split between the OEM FPCM and the Vaporworx controller. Overall it's very clean and I expect it to be durable. The OEM FPCM is still probably not going to like more than 15 volts, but since the DW300s can pull 14-15 amps each (at 13.5 volts!) with higher line pressure, this mod should allow me to exploit their full potential with higher PSI without frying another FPCM.
![Rectangle Line Font Parallel Slope]()
The cool part is Vaporworx has several different controllers, so I picked up a second one from a forum member that is MAP-triggered (3 pis but you can choose higher pressures if desired). So I will be replacing my Dsteck module with that, to drive my external Auxillary pump off the second Vaporworx controller - so that all three pumps are pulse-width controlled and hopefully I'll be able to reduce some of the fuel pressure spikes that happen when the Auxillary pump kicks on.
This controller is similar, but has three wires: the orange/green are +/- to the MAP sensor in the blower, and the gray wire is again the PWM signal that piggy backs off the same gray wire as the first controller. So both controllers will be in the trunk, with just the power and signal wires running up to the front of the car. That install will come later.
![Yellow Electrical wiring Audio equipment Gadget Cable]()
Caveat: this is just ONE option. I still have to experiment with tuning the pump duty cycles and voltages to reduce the fuel pressure spikes and pump modulation that happens with the OEM module - because it is still in control! But, after frying one FPCM and having to replace it, I found this to be an interesting and promising option for our cars since so many of us are running aftermarket in-tank pumps and Aux pump kits.
Many people would rather go to a return-system and skip all this stuff. But my car is more of a hobby than a specific goal, and it's a fun challenge to try out different options. I've never heard of Vaporworx before Adam112 told me about them, and Carl (of Vaporworx) makes quality stuff. He also answers his phone pretty much 24-7 and will talk your ears off with advice, explanations and talking over your build I found him to be a really nice guy to talk to and very helpful - so I wanted to give him a special plug here.
Definitely check out his website for any fuel control needs you have.
One option, to fully maximize the DW300 in-tank pumps, is to split the current between the FPCM itself and a second driver - enter the Vaporworx Ally controller. It's pretty slick, as it emulates the OEM FPCM signal for pump pulse-width modulation to drive the second pump as if both were still controlled by the OEM module, but it can handle 40 amps itself. So you're effectively cutting the current draw through the OEM module by half (as it's only driving one of the in-tank pumps, and the Vaporworx module carries the second pump).
In other words, you can think of the Vaporworx module as a stand-alone relay that mirrors the signal from the FPCM, but Carl (of Vaporworx) has built them to handle way more current than any in-tank pump can draw, and in this setup the life expectancy of his modules is 90+ thousand miles give or take.
Running the wires in a suitable manner is the hardest part of this install, but the whole think took me about 5 hours due to cutting, splicing and running conduit under the car and fishing it up to the fuel hat (see below).
Vaporworx Ally controller (website)
The controller is simple: +12V and Neg to the battery terminals, +12 and Neg to either of the in-tank pumps, pinning them into the connector at the top of the fuel hat, and a signal wire either of the Neg pump wires (for the PWM signal). There is an option to wire in a BAP also, but it's probably not needed for our cars in this scenario.
Easy option: run your +/- wires to the pump connector along the side of the trunk under the rear seats to your cut-out (because you have cut out an access panel by now surely). But your wires will be exposed under the rear seat and where they drop down to the fuel hat, so I don't recommend this.
Hard option: run your wires through the grommet in the battery compartment, which drops down to the passenger rear quarter panel behind the rear subframe. From here, you can snake them over the subframe to the gas tank and fish them up to the fuel hat and pump connector. This takes a while, but is easily done with a flashlight, a few jack stands and some patience.
I just punched a hole in the grommet (it's very thin, but pliable) and taped the Pos/Neg and signal wires together. Push them through and find them by pulling back the rear wheel well cover. Pull out about 6 feet of wire, then wrap them in sheathing.
It was hard to get photos here, but using the OEM harnesses under the car you can fish them over the rear suspension and rear subframe, using zip ties as needed, and then work the wires to the tank. I dropped a spare wire from the top of the tank down, taped it to the bundled wires and then pulled it back up to the fuel hat:
Now you need to strip the three wires and install the provided terminals with a good crimp. I de-pinned one channel (a gray and red wire), and replaced them with the red/black (Pos/Neg) wires I just pulled up. Note: the two sets of wires that control the pumps are Tee'd off from a single Pos/Neg feed from the FPCM, so it doesn't matter which side you use. The third, gray wire is the PWM signal and can be connected to the gray (neg) wire you just de-pinned, as it is still receiving the signal from the FPCM; I used a spare GT280 connector I had laying around but it could be crimped, soldered or whatever.
The remaining red +12V wire needs to be terminated safely to avoid shorting - I used a few layers of heat-shrink to cover the exposed terminal, while allowing me to re-install it down the roead if needed.
Then connect the Vaporworx controller using the supplied terminals and the wires you just ran:
+/- to one of the in-tank pumps (red/black)
+ to the Positive Battery terminal (orange, fused)
Gray PWM signal to the de-pinned gray wire from the fuel pump connector (at the fuel hat)
Neg (black) to the battery ground into the chassis just to the rear of the battery
Car starts right up and functions normally with both pumps running, however the total current draw is now split between the OEM FPCM and the Vaporworx controller. Overall it's very clean and I expect it to be durable. The OEM FPCM is still probably not going to like more than 15 volts, but since the DW300s can pull 14-15 amps each (at 13.5 volts!) with higher line pressure, this mod should allow me to exploit their full potential with higher PSI without frying another FPCM.
The cool part is Vaporworx has several different controllers, so I picked up a second one from a forum member that is MAP-triggered (3 pis but you can choose higher pressures if desired). So I will be replacing my Dsteck module with that, to drive my external Auxillary pump off the second Vaporworx controller - so that all three pumps are pulse-width controlled and hopefully I'll be able to reduce some of the fuel pressure spikes that happen when the Auxillary pump kicks on.
This controller is similar, but has three wires: the orange/green are +/- to the MAP sensor in the blower, and the gray wire is again the PWM signal that piggy backs off the same gray wire as the first controller. So both controllers will be in the trunk, with just the power and signal wires running up to the front of the car. That install will come later.
Caveat: this is just ONE option. I still have to experiment with tuning the pump duty cycles and voltages to reduce the fuel pressure spikes and pump modulation that happens with the OEM module - because it is still in control! But, after frying one FPCM and having to replace it, I found this to be an interesting and promising option for our cars since so many of us are running aftermarket in-tank pumps and Aux pump kits.
Many people would rather go to a return-system and skip all this stuff. But my car is more of a hobby than a specific goal, and it's a fun challenge to try out different options. I've never heard of Vaporworx before Adam112 told me about them, and Carl (of Vaporworx) makes quality stuff. He also answers his phone pretty much 24-7 and will talk your ears off with advice, explanations and talking over your build I found him to be a really nice guy to talk to and very helpful - so I wanted to give him a special plug here.
Definitely check out his website for any fuel control needs you have.
