How FUELAB's Electronic Fuel Pressure Regulator Works

This article will describe how FUELAB’s 529xx Series Electronic Fuel Pressure Regulators work, and the functionality that they provide. 529xx Series regulators can be categorized as a Bypass Style regulator with distinct features. We will expand on that information, with focus on how the FUELAB electronic regulator works with EFI.

Cutaway View of the FUELAB 529xx Series Electronic Fuel Pressure Regulator: (click on image to enlarge) 529 Article 1

Example of the Plumbing Circuit used with the Electronic Pressure Regulator: (click on image to enlarge)

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How FUELAB’s 529xx Series Electronic Fuel Pressure Regulators Work 529xx Series electronic regulators are designed to be compatible only with externally mounted FUELAB Prodigy Electronic Fuel Pumps, and internally installed FUELAB Power Modules. Just like standard Bypass Style regulators, 529xx Series electronic regulators control fuel flow and pressure with a mechanical regulator and diaphragm assembly that relieves fuel pressure by sending excess flow back to the fuel tank once the set pressure is achieved. However, the FUELAB electronic regulator takes this action one step further by placing a restriction valve along the return line to build return line back pressure.

The electronic component of 529xx Series electronic regulators is the pressure transducer that is positioned to monitor the fuel return line back pressure, and use this information to control the Prodigy Fuel Pump. If the pressure being read is too high, it signals the pump to slow down. If the pressure is too low, it signals the pump to speed up. Speed control allows the pump to operate at reduced speed during low fuel demand conditions, helping to keep fuel cooler, which helps to avoid vapor lock and cavitation damage. It also allows the return line flow rate to be relatively constant, which has the effect of negating the regulator’s inherent mechanical regulation slope (this value is the amount of fuel pressure change per amount of flow rate difference through the regulator), thereby helping keep fuel pressure more stable. A video demonstrating the speed control function can be seen at

Of note, this system is unique to FUELAB; FUELAB Electronic Fuel Pressure Regulators, and the operation of the speed control system are patented. 529xx Series electronic regulators are not compatible with pressurized reservoirs, such as swirl tanks. It can cause erroneous pressure transducer readings. The regulators must be returned to a vented fuel tank.

This concludes the description of how FUELAB's electronic regulator works. In a future segment we will cover fuel how system diagnostics can be performed utilizing 529xx Series Electronic Fuel Pressure Regulators, including how the regulator can be modified to act as a normal bypass regulator, and how the analog output can be used.

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