ASTM D5598-01(2012)

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.

5.2 Test Validity:

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 and health practices and determine the applicability of regulatory limitations prior to use.