LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> GMC >> 1983 >> Forward Control 4.8 T, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Fuel Injection System - Diesel >> Testing >> Injection Nozzle >> Leakage Test
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Leakage Test

  1. Open tester shut off valve to pressure gauge an additional 1/2 to 1 1/2 turns. Blow dry nozzle tip. Connect a short piece of clear plastic tubing to each fuel return fitting on nozzle.
  2. Slowly depress tester lever until pressure gauge reads 1400 psi (98 kg/cm2 ). Maintain pressure for 10 seconds and observe nozzle tip.
  3. Replace nozzle assembly if drop of test fluid drops from tip within 10 seconds. A drop may form but not drop off within the specified time period. See Fig 1. Release tester pressure.
Fig 1: Nozzle Leakage Test A drop of test fluid may form but not drop off within 10 seconds.
G8733