E31 BMW Fuel Pump - 840i 840Ci 850Ci Old BMW Part Number: 16141182289

The Complete Fuel Pump Assembly is designed for BMW E31 V8 840i, 840ci, and V12 850Ci models. It is compatible with V8 M60 and M62 engines from 1994 to 1999, as well as V12 M73 engines from 1995 to 1999. This assembly is located under the passenger rear seat and includes a top rubber seal.

It is important to clarify that this is not a 3D printed part; rather, this pump has undergone over two years of development. Each component is precision injection molded, mirroring factory standards, with all identified shortcomings of the original design systematically addressed.

The following changes and improvements have been made to enhance the original design:

1. A significant issue with the original fuel pump assemblies is that up to 50% may develop leaks at the mold "parting line" beneath the injection point mark due to thermal expansion and contraction over time, leading to micro-cracks. The new design eliminates this problem by ensuring that the top cap is universally strong and resistant to cracking over the long term.

2. The original BMW pump assembly features brittle plastic preformed fuel lines that connect to rubber hoses and subsequently to the fuel pump motor. While this design may have sufficed three decades ago, the introduction of modern, more corrosive fuels such as E10 in Europe and ethanol additives in the United States has led to rapid degradation. This degradation causes significant pressure leaks at the fuel pump motor connection and through cracks in the older plastic lines, resulting in rough idle, reduced power from one or both banks, and a lean running condition. The new design significantly improves upon the original by utilizing high-pressure fuel-resistant corrugated PTFE lines that run directly from the top of the pump unit to the pump motors, thereby eliminating the need for rubber hoses. These lines are heat-pressed onto fuel pump fittings and securely clamped to ensure there are no pressure leaks.

3. The original BMW wiring is insulated with material that offers only partial resistance to standard fuel, let alone E10. Over time, wires can delaminate, leading to electrical shorts. The new assembly uses high-quality 600v military-grade PTFE insulated wire, which is designed to endure for an extended period within the tank. Additionally, the ground wire connection has been redesigned to remove the exposed crimped joint, reducing the risk of short circuits.

4. The original BMW fuel pump motors feature copper commutators, which have been replaced with modern, quiet carbon commutator motors that offer a lifespan three times greater in fuel. The new pump motor can deliver up to 150 LPH on demand (an increase from the OEM 140 LPH) while maintaining the factory pressure of 3.5 BAR precisely.

5. Although the fuel level sensor retains a similar shape, it has been redesigned with modern components to enhance precision and longevity.

A standard one-year full parts replacement warranty is included with this assembly.