Picture of the VaporWorx Fuel Pump PWM Controller

Wiring VaporWorx Fuel Pump Controller

We always say that our Infinitybox system plays nicely with other electrical accessories in your car.  This blog post is another great example of that.  We got a call from a customer asking about wiring the VaporWorx Fuel Pump Controller with his Infinitybox 20-Circuit Kit.  He was worried about having to wire in additional relays and run a lot of wire.  In reality, wiring the VaporWorx Fuel Pump Controller is simple and easy with the Infinitybox system.

The VaporWorx guys make some very cool products.  Click here to get to their website.  You have to appreciate a company with the tagline “We Give You Gas”.  Their core products improve the delivery of fuel in your resto-mod, street rod, hot-rod or Pro-Touring build.  They have been innovating products for reliable fuel delivery in cars with EFI systems since 2009.

Their core products are designed for returnless fuel systems.  There is only one fuel line going from the in-tank pump to your fuel rail.  There is no fuel regulator on the rail and no return line that brings excess fuel back to the tank.  Their Fuel Pump Controller mounts in the rear of the car, near the fuel pump.  It actively monitors the fuel pressure in the line at the outlet of the pump.  Using pulse-width modulation (PWM), they vary the pump power to keep the fuel pressure within a tight window.  This reduces dead-heading of the fuel pump and also reduces the amount that the fuel gets heated.  We use PWM to control things like fan speed and light dimming from our POWERCELLs and have blogged about how that works before.  Click on this link to learn more about PWM.

This blog post is going to walk you through wiring the VaporWorx fuel pump controller with our Infinitybox system.  We are only going to cover the connections from the battery, from the POWERCELL and to ground.  See their manual for more details on the rest of the sensor wiring required for their controller.  You can access the manuals and installation instructions for their products by clicking this link.

Just like any other blog post where we talk about integrating the Infinitybox system with other products, please carefully read and understand all of the steps required to install the VaporWorx Fuel Pump Controller.  You are messing with flammable fuel and electricity.  Make sure you are completely comfortable with doing this job.

For the sake of this blog post, there are three connections that we are going to cover: primary power from the battery, the fuel pump trigger from the POWERCELL and the grounds.

The primary power for the fuel pump controller is going to come directly from the battery.  This should be a simple connection since the controller should be mounted close to the pump in the tank and most guys are relocating their batteries to their trunks.  Follow the recommendations from VaporWorx for the gauge of wire going from the positive terminal on the battery to the BAT+ terminal on their module.  It is very important that this gauge of wire is sized correctly and that it is fused as close to the battery as possible.

Next, the fuel pump controller and the fuel pump need to be grounded.  The VaporWorx team recommends that you ground their pump controller and the fuel pump directly to the negative terminal of the battery.  This should be easy in most installs since guys are relocating the batteries to their trunks.

Last, the VaporWorx controller needs a fuel pump enable signal from the ECU.  When wired with the Infinitybox system, this signal is going to come from the fuel pump output on your rear POWERCELL.  In most 20-Circuit Kits, this is the TAN wire on the rear POWERCELL but check your configuration sheet for details on this output.  The POWERCELL output is going to connect to the blue wire in the GT150 connector.

The advantage of using the POWERCELL to supply the fuel pump enable signal is that you do not need to add any additional wiring.  You already have the POWERCELL located in the rear of your car.  You do not need to run a wire from the front of the car to the back.  You can simply use the POWERCELL to supply this signal.

Once you have power, ground and the fuel pump enable signal wired, you need to wire your EFI system to your Infinitybox MASTERCELL.  This is how the POWERCELL knows when to turn on the output for the fuel pump enable signal.  To do this properly, you need to understand if your EFI system uses a ground trigger for the fuel pump or a positive signal for the fuel pump.  The wiring diagram for your EFI system will define this.  Alternately, we have wiring diagrams for all of the popular EFI systems in the Resources section of our website.

If your EFI system sends a ground trigger for the fuel pump enable signal, you can wire the MASTERCELL fuel pump input to the EFI system’s fuel pump output.  We strongly recommend wiring a diode in series to buffer the MASTERCELL from the ECU.  As an example, the FAST XFI 2.0 sends a ground trigger for the fuel pump enable signal.  You can see how the recommended diode is wired at this link.

If your EFI system sends a positive trigger for the fuel pump enable signal, you need to flip this to a ground trigger.  You can use one of our inVERT Mini Buffers to do this easily.  The Holley Sniper EFI System uses a positive trigger for the fuel pump enable signal.  You can see how to wire in the inVERT Mini at this link.

This wiring diagram shows you all of the connections between our Infinitybox system and the VaporWorx Fuel Pump Controller.  You can download a PDF version of it by clicking this link.

Picture of the Infinitybox wiring diagram showing how to wire the VaporWorx Fuel Pump PWM controller with the Infinitybox system

Picture of the Infinitybox wiring diagram showing how to wire the VaporWorx Fuel Pump PWM controller with the Infinitybox system

Please note that some wires are omitted from our diagrams to make them more clear.  Carefully follow the instructions that came with your Infinitybox system and the VaporWorx module for the full instructions.  Also note that the MASTERCELL input and POWERCELL output wire colors may vary depending on your specific kit and the options you have.  Always follow the configuration sheet that came with your kit.

Click on this link to contact our technical support team with any questions about wiring your VaporWorx Fuel Pump Controller with our Infinitybox system.

Examples of three different PWM duty cycles

Pulse Width Modulation

Our Infinitybox System is far different from a traditional fuse & relay based wire harness.  There are things that Infinitybox can do that you couldn’t even begin to imagine with a good-old bundle of wire.  One of our biggest goals when we educate people about our products is to de-mystify some of the potentially scary terms that we use.  One that we use a lot is Pulse Width Modulation or PWM.  This is a fancy term for turning something on and off very fast to control power.

We don’t use relays in our POWERCELLs.  Instead, we use MOSFETs.  Yes, I know that is another scary term that we’ll talk about later.  For now, all you need to know is that MOSFETs are solid state stitches.  Unlike relays, there are no mechanical parts in them.  You can turn a MOSFET on and off literally millions of times per second.  You can do that with a relay 2 to 3 times per second before you have to worry about burning up the contacts.

The ability to turn a MOSFET on and off very quickly allows us to control the amount of power coming out of a POWERCELL output.  We do this by using something called Pulse Width Modulation.  PWM is the process of turning an output on and off quickly.  The effective power coming out of the output is proportional to the amount of on time as compared to the off time.  The ratio of the on time versus the off time is called the duty cycle.  So for example, if we turn the output on for half of the cycle time and off for the other half, your duty cycle is 50%.  The effective voltage of your output is approximately 50%.  This picture shows you what we mean.

Examples of three different PWM duty cycles

Examples of three different PWM duty cycles

The three different graphs are 10%, 50% and 90% duty cycle.

Check out this video showing you more about PWM.  If you haven’t seen Colin’s Lab on You Tube before, it is a worthwhile watch.  He is a geek’s geek but makes great videos explaining the basics of electronics.  As part of Make Magazine, his stuff is filled with tons of useful electronics projects, tips and tricks.

So you’re asking yourself, “What does this mean to me”?  “I’m wiring a car, not building circuits.”  Pulse Width Modulation is a very effective and efficient way to control the brightness of lights and the speed of motors.  There is very little heat lost with PWM as compared to using resistors or rheostats.

The Infinitybox system has PWM capability built into the POWERCELL outputs.  We can effortlessly dim lights, create daytime running lights, theater dim interior lights, control fan speeds, and fuel pump speeds.  For those who need that advanced control, it is built right into your system.  No external modules or hardware are required.

Click on this link to contact one of our technical support guys to talk about your specific requirements using Pulse Width Modulation.

Picture of a Spal Cooling used in our 1967 Mustang wired with Infinitybox

Cooling Fan

We’re getting towards the end of the outputs that we need to wire on this 1967 Mustang project.  The cooling fan is next.  We’ll talk in later posts about how to wire the cooling fan triggers to the MASTERCELL input.  This post is going to talk about connecting the POWERCELL output to the fan motor.

In most cars, the cooling fan is connected to the radiator in the front of the car.  When the engine coolant temperature exceeds a set point, the cooling fan turns on to blow outside air through the radiator.  The fan will continue to run until the coolant temperature drops below a set level.

There is a dedicated output on the front POWERCELL in the 20-Circuit Kit that our customer is installing in this 1967 Mustang.  It is output 10, which is the tan wire on the A connector.  Check your specific configuration sheet to confirm the wire color.

Our POWERCELL acts as both the fuse and relay box, except we don’t use relays.  We use what is called a MOSFET.  Think of this as a solid state relay.  Each of the outputs on a POWERCELL can carry 25-amps continuously.  These outputs can also tolerate in-rush currents up to 100-amps.  Like our previous post about headlights and high-beams, you need to consider the in-rush on a motor when you are planning on wiring your car.

When an electric motor is started, the rotor appears to be stalled at the instant the current is applied.  This stalled current will flow through the motor windings.  As the motor starts to turn, the amount of current flowing to the motor will drop.  When the motor reaches its steady-state speed, the current will level off.  This initial in-rush current can be 4 to 5 times the steady-state current depending on the size of the motor.  The graph below shows an example of this in-rush current.

Graph showing the start-up current of a cooling fan

Graph showing the start-up current of a cooling fan

In the case of this fan motor, the initial in-rush is approximately 100-amps.  Within 2 seconds of starting, the current levels off at about 25-amps.

In most cooling fans, the manufacturer will tell you that you need to use a 70-amp relay to turn the fan on and off.  This is because of the starting current or in-rush current going to the motor.  With your Infinitybox system, you can drive most cooling fans directly without adding an external relay.  The outputs used in the POWERCELL outputs are designed to handle this in-rush current.

In addition to just handling the in-rush current, we use an extra trick to help manage this in-rush current.  As mentioned above, we don’t use relays on our outputs.  We use MOSFETs.  MOSFETs can be turned on and off thousands of times per second.  You can’t do that with a relay.  This on and off lets us do something called Pulse-Width Modulation or PWM.  There are two important parts of PWM.  The first is the frequency.  This is how many times you turn the MOSFET on and off each second.  Our PWM frequency is 20,000 Hertz.  The second part is duty cycle.  This is the ratio of the on time over the off time.  A 50% duty cycle would have the output on for the same period of time as it is off.  A 100% duty cycle means that the output is on all the time.  A 0% duty cycle means that the output is off.  This picture shows the PWM pulses and different duty cycles.

Examples of three different PWM duty cycles

Examples of three different PWM duty cycles

By changing the duty cycle, we can control the amount of power going to the fan.  The higher the duty cycle, the more power is coming out of the POWERCELL output.  When we turn on a fan, we soft-start it.  This means that we gradually start the fan over about one second.  This minimizes the in-rush current.

We get lots of questions about cooling fans and whether or not they can be driven directly from the POWERCELL.  Most can.  A good rule of thumb is to look at the gauge of wire on the cooling fan.  If it is 14-AWG or less, you can certainly use our POWERCELL directly.  In most cases, the manufacturer of the fan will publish the running current or steady-state current for the fan.  Most commonly used fans in aftermarket applications draw between 8 and 20-amperes.

In some cases, our customers want to use two large fans to cool their engines.  The two fans together would draw more than the 25-amps maximum of a single output.  In this case,  you can use any of the OPEN outputs on your configuration sheet.  OPEN means that there is no specific function assigned to them.  You can use them as auxiliary outputs.  We’ll talk about wiring the cooling fan triggers to the MASTERCELL in a few more posts.

DC fan motors have a direction to them.  One of the fan wires will connect to the POWERCELL output and provide battery power to the motor.  The second wire must be connected to ground.  You must check the manual that came with your fan to determine which wire is power and which is ground.  You can also watch the rotation of the motor.  Most fan manufacturers put an arrow that indicates the correct direction that it should spin.  If the fan spins in the wrong direction, reverse the wires.

You can splice the POWERCELL output wire to the wires on the fan in the same way that we described in our headlight post.  You can get to that post by clicking this link.

Keep watching for updates on this 1967 Mustang wiring job with our 20-Circuit Kit.  If you have questions or comments, you can click on this link to get in touch with our team.