Spray Pattern Test

Remove injection nozzles. Clean carbon from tip of nozzle with a soft brass brush. Check torque of inlet fitting to nozzle body and correct as necessary.

Fig 1: Nozzle Spray Pattern Test
Courtesy of GENERAL MOTORS COMPANY
Assemble nozzle to a suitable diesel injection nozzle tester using a connecting line (high pressure) 12" long by 1/4" O.D by 1/16" I.D. between nozzle and tester. Refer to test equipment manufacturers' instructions for exact tester operating instructions.
CAUTION: When testing nozzles, keep spray contained to avoid serious injury. DO NOT allow injector to release line pressure on hands, arms or any part of body. Pressure of atomized test spray has sufficient penetrating power to puncture flesh.

Fig 2: Injection Nozzle Seat Tightness Test
Courtesy of GENERAL MOTORS COMPANY
Build nozzle pressure slow enough to determine exact minimum opening pressure of nozzle. Minimum opening pressure is 1750-1900 psi (Roosa-Master) or 870 psi (Diesel Equipment/C.A.V. Lucas). When nozzle releases pressure, note spray pattern and compare with examples shown. If incorrect, or if a liquid stream, replace nozzle. See Fig 1.