Aeromotive VaporWorx Dual Fuel Pump Returnless Pulse Width Modulation Fuel Module Controller Kit

Precision Dual Pump Fuel Control for Returnless High-Horsepower Street and Forced Induction Builds

The Aeromotive 66138 is the VaporWorx PWM controller kit designed for returnless dual fuel pump applications in forced induction and high-horsepower street builds. Operating without a return line, this controller modulates two brushed fuel pumps via pulse width modulation, ramping output up and down with demand to keep pumps running at the lowest speed necessary for the current throttle and boost condition. The result is lower pump temperatures, quieter operation, and extended pump life compared to a constant full-voltage dual pump setup. A 3-bar MAP sensor provides boost reference for automatic output scaling across the entire boost range.

Key Features

• Aeromotive 66138 returnless PWM controller for dual fuel pump configurations
• Pulse width modulation matches pump speed to real-time fuel demand
• Returnless system compatibility, no return line routing required
• 3-bar MAP sensor for boost-proportional pump speed control
• Remote mount design for flexible chassis placement
• Compatible with brushed-type fuel pumps in surge tank or in-tank configurations
• Reduces pump heat and noise at cruise and idle
• Suitable for supercharged, turbocharged, and high-power naturally aspirated builds running dual pumps

Specifications

What's Included

• 1 Aeromotive 66138 returnless dual pump PWM controller
• 3-bar MAP sensor
• Wiring harness and hardware for installation

About Aeromotive

Aeromotive has been at the forefront of high-performance fuel system engineering since 1994. Based in Lenexa, Kansas, Aeromotive designs and manufactures fuel pumps, regulators, filters, fittings, and complete fuel system solutions for street performance, drag racing, road racing, and extreme high-power builds. The VaporWorx line represents Aeromotive's demand-matched PWM fuel control technology for modern high-horsepower applications.

Related Parts on Our Site

• Aeromotive 66171 VaporWorx ReturnX Triple/Quad Pump SC Controller
• Aeromotive 66166 VaporWorx ReturnX Dual Pump NA Controller
• Aeromotive 66141 VaporWorx Gen 2 CTS-V Returnless Controller

Frequently Asked Questions

The Aeromotive 66138 is the VaporWorx returnless dual fuel pump PWM controller kit. It uses pulse width modulation to manage two brushed fuel pumps in a returnless fuel system, scaling pump speed with boost pressure via an included 3-bar MAP sensor to match fuel delivery precisely to engine demand.

A returnless system regulates fuel pressure at the pump or fuel module and does not route excess fuel back to the tank through a dedicated return line. A return-type system uses a pressure regulator near the injectors and returns excess fuel to the tank via a return line. The 66138 is designed exclusively for returnless configurations, while the 66166 and 66171 are return-type (ReturnX) controllers.

The 66138 is a universal remote-mount controller compatible with any vehicle running a returnless dual brushed fuel pump configuration. Common applications include late-model GM LS and LT-swapped builds, Mustang and Dodge Challenger high-horsepower builds, and any custom chassis where dual in-tank or surge-tank brushed pumps are used in a returnless setup.

The 3-bar MAP sensor reads intake manifold pressure and provides a real-time boost signal to the 66138 controller. As boost pressure climbs, the controller automatically increases PWM duty cycle to ramp both pumps toward full output. This eliminates manual tuning for most applications and ensures pump speed always matches actual fuel demand rather than running at fixed full speed.

Yes. The 66138 supports dual brushed pumps in surge tank configurations as well as dual in-tank pump setups. Ensure your surge tank and pump selection are compatible with a returnless pressure control strategy before installation.

No. The 66138 is designed for brushed-type fuel pumps. Brushless pump controllers use a fundamentally different drive signal and frequency, and are not compatible with Aeromotive's current PWM VaporWorx controllers. Confirm your pump type before purchasing.

The included 3-bar MAP sensor covers boost levels up to approximately 29 PSI above atmospheric (approximately 43.5 psia absolute), suitable for most street and moderate track forced induction builds. For builds exceeding these boost levels, consult Aeromotive's technical team about alternative MAP sensor options.

The 66138 is a standalone controller and is not designed to piggyback OEM fuel system control modules (FSCM). If your vehicle uses an OEM FSCM, consider Aeromotive's BoostWorx or OEM piggyback series controllers that are specifically designed for FSCM-equipped platforms.

Installation Instructions

1. Confirm your vehicle uses a returnless fuel system before installing the 66138.
2. Select a remote mount location for the controller with adequate clearance and away from heat sources.
3. Install the included 3-bar MAP sensor in the intake manifold or plenum.
4. Connect PWM output wiring to each of the two fuel pump relays or directly to pump terminals per the included wiring diagram.
5. Run the main power feed with appropriately gauged wire and fusing for dual pump current draw.
6. Power up the system and verify MAP sensor signal at idle.
7. Confirm fuel pressure stability at idle and partial throttle before full-power testing.

WARNING: This product can expose you to chemicals including lead and phthalates, which are known to the State of California to cause cancer and reproductive harm. For more information go to www.P65Warnings.ca.gov.