5.1 Test Method—Deposits are prone to form on the metering surfaces of pintle-type electronic fuel injectors. These deposits reduce fuel flow through the metering orifices. Reductions in metered fuel flow result in an upset in the air-fuel ratio, which can affect emissions and driveability. When heavy enough, these deposits can lead to driveability symptoms such as hesitation, hard starting, loss of power, or a combination thereof, that are easily noticed by the average driver and lead to customer complaints. The mechanism of the formation of deposits is not completely understood. It is believed to be influenced by many factors, including driving cycle, engine design, port fuel injector design, and composition of fuel used. The procedure in this test method has been found to build deposits in injectors on a consistent basis. The deposits formed by this procedure are similar to the deposits experienced in the field in terms of composition and in amount of deposition. This procedure can be used to evaluate differences in unleaded base fuels and fuel additives.

5.1.1 State and Federal Legislative and Regulatory Action—Legislative and regulatory activity, primarily by the state of California6 and the Federal Government7 necessitate the acceptance of a standard test method to evaluate the port fuel injector deposit-forming tendency of an automotive spark-ignition engine fuel.

5.1.2 Relevance of Results—The operating conditions and design of the engine and vehicle used in this test method are not representative of all modern automobiles. These factors must be considered when interpreting test results.

5.2 Test Validity: 

5.2.1 Procedural Compliance—The test results are not considered valid unless the test is completed in compliance with all requirements of this test method. Deviations from the parameter limits presented in Section 10 will result in a void test. Engineering judgment must be applied during conduct of the test method when assessing any anomalies to ensure validity of the test results.

5.2.2 Vehicle Compliance—A test is not considered valid unless the vehicle has met the quality control inspection requirements in accordance with 8.2.

1.1 This test method covers a vehicle test procedure to evaluate the tendency of an unleaded spark-ignition engine fuel to foul electronic port fuel injectors (PFI).

1.2 The test method is applicable to unleaded spark-ignition engine fuels which may contain antioxidants, corrosion inhibitors, metal deactivators, dyes, deposit control additives, and oxygenates.

1.3 The values stated in SI units are to be regarded as the standard. The values in parentheses are provided for information only.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given throughout this test method.

Note 1: If there is any doubt as to the latest edition of Test Method D5598, contact ASTM Headquarters. Other properties of significance to spark-ignition engine fuel are described in Specification D4814.

1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.