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Home >> Volkswagen >> 1993 >> Passat GL, 2.0 C, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System/Component Tests - 4-CYL >> Fuel System >> Fuel Injectors
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Fuel Injectors

  1. Ensure fuse No. 18 in fuse/relay panel is okay. Remove fuel pump relay from fuse/relay panel. Connect Test Harness (VAG 1348/3-2) to terminal No. 4 of fuel pump relay socket. Connect Remote Control (VAG 1348/3A) to test harness and battery positive terminal.
  2. Carefully pull injectors out of their inserts and place complete assembly into Fuel Analyzer (VAG 1348/2B). Ensure fuel lines are not twisted or kinked. Turn and lift adjustment screw, slide, and knurled nut of Sensor Plate Positioner (VAG 1348/1A) to upper position. See Fig 1 .
  3. Center positioner on edge of airflow sensor, with pointer of positioner facing fuel distributor. Hold airflow sensor plate in rest position and push slide in to stop.
  4. Turn adjustment screw in until magnetic tip contacts sensor plate mounting bolt. Operate remote control and turn positioner adjustment screw out far enough so that start of spray becomes visible at one injector.
  5. Turn off remote control and empty analyzer (fuel injectors remain inserted in analyzer). Push in slide to first stop position (idle simulation) and observe injector spray patterns. If spray pattern for one injector is different, lift sensor plate briefly and repeat test.
    Fig 1: Testing Fuel Injectors
    G93D81102Courtesy of VOLKSWAGEN UNITED STATES, INC.
  6. Operate remote control until 20 ml (milliliters) of fuel accumulates in one of the tubes. Compare fuel quantities for each injector while holding analyzer level. Maximum variation between injectors is 2.0 ml.
  7. If fuel quantity varies more than 2.0 ml, interchange those injectors and repeat test. If fuel quantity changes between interchanged injectors, replace injectors.
  8. If fuel quantity remains the same between interchanged injectors, check for a pinched fuel line or defective fuel distributor. Repair or replace as necessary.
  9. If fuel quantity variation between injectors is within 2.0 ml, empty fuel analyzer. Pull slide on positioner to second stop (full throttle simulation) and observe injector spray patterns. If spray pattern for one injector is different, lift sensor plate briefly and repeat test.
  10. Operate remote control until 80 ml of fuel accumulates in one of the tubes. Compare fuel quantities for each injector while holding analyzer level. Maximum variation between injectors is 8.0 ml.
  11. If fuel quantity varies more than 8.0 ml, interchange those injectors and repeat test. If fuel quantity changes between interchanged injectors, replace injectors.
  12. If fuel quantity remains the same between interchanged injectors, check for a pinched fuel line or defective fuel distributor. Repair or replace as necessary.
  13. Place airflow sensor plate at rest (leak test) position. Operate remote control for 2 minutes, to pressurize fuel injectors. Fuel injectors must not leak.
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