Fuel System - Damage Caused By Fuel Contaminants

May 2006
Technical Service

SI B 13 03 06
Fuel Systems

SUBJECT
Fuel Pump Failure after Refueling with Ethanol Fuel Blend

MODEL
All

SITUATION
Engine dies shortly after refueling, and cannot be restarted again.

CAUSE
Fuel contamination related to a recent introduction of ethanol fuel blends. Ethanol is used as an octane booster, and replaces MTBE (methyl tertiary-butyl ether) in many fuel formulations. High levels of water and other residue contaminants may cause damage to a fuel delivery system.

The introduction of ethanol to existing storage tank and distribution systems has acted to absorb the build-up of water and free residual contaminants accumulating over a period of time at these locations and permits them to be pumped into vehicles at the time of refueling. Aside from the engine not running, early tests on vehicles with severe contamination reveal, for example, oxidation as the cause for fuel pump seizure on the E46 and a clogged fuel filter as the cause for a ruptured in-tank fuel line on the E65/66 N73 (760Li/i).

CORRECTION
In case of a fuel delivery system failure after refueling, follow the procedure below:

1. Drain all contaminated fuel from the fuel tank and fuel lines.

2. Clean all deposits/residue from the bottom of the fuel tank.

3. Replace the fuel filter/regulator assembly

4. Replace the fuel pump if seized, or if the in-tank pressure line is ruptured.

NOTE:
For more information related to ethanol fuel blends refer to SI B13 01 06 (Alcohol Fuel Blends in BMW Vehicles).

WARRANTY INFORMATION
BMW NA does not cover damage caused by contaminated fuel. Customers should be directed to the facility where the fuel was purchased.