1. Remove the front center mounting bolt from the air inlet and install J 39307 adapter with a 6 to 7 foot length of S c inch I.D. rubber line. Then route the rubber line into the cab and connect J 28474 pressure gage to the end of the line.
2. Test drive the vehicle with a passenger watching the gage. Allow the vehicle to coast at engine idle speed in first gear. Then press the accelerator pedal to the floor while the passenger notes the boost pressure reading. A boost reading of 14 kPa (2 psi) or more indicates the turbocharger is operating properly.
