Technicians operated a 1985 BMW 318i, that is specified in the test, on a test track under controlled cyclic conditions for 10,000 miles (16,000 km), simulating a mix of city, suburban and highway driving.
The 1985 BMW 318i is powered by a 1.8L, 4-cylinder, port-fuel-injected, single-cam engine. Per ASTM specifications, the vehicle was also equipped with an automatic transmission and air conditioning.
The ASTM standard is adapted so that the initial 10,000 miles running on additive-free fuel must cause average deposits of greater than 290mg per intake valve. After addition of Gumout and running for one tank of fuel, fewer than 100mg of deposits remained on valves, signaling a successful passing score.