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Home >> Saturn >> 1999 >> SW2 Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - System Testing & Engine Component Tests >> Fuel System >> Fuel Control >> Fuel Injector Balance Test
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Fuel Injector Balance Test

NOTE: Allow engine to cool down to avoid irregular readings due to "hot soak" fuel boiling. To prevent flooding, the fuel injector balance test should not be performed more than once without starting and running engine.
NOTE: If injectors are dirty, they should be cleaned using approved injector cleaning procedure before performing fuel injector balance test.
  1. If On-Board Diagnostic (OBD) system check has been performed, go to next step. If On-Board Diagnostic (OBD) system check has not been performed, perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK in appropriate SELF-DIAGNOSTICS article.
  2. If fuel injector coil test has been performed, go to next step. If fuel injector coil test has not been performed, perform fuel injector coil test. See INJECTOR COIL TEST - ECT BETWEEN 50-95°F .
  3. If engine coolant temperature is less than 201°F (94°C), go to step  5. If engine coolant temperature is greater than 201°F (94°C), go to next step.
  4. Allow engine to cool until coolant temperature is less than 201°F (94°C), then go to next step.
  5. Install fuel pressure gauge. Turn ignition on, and then off. Bleed air from fuel pressure gauge. Using scan tool, energize fuel pump. Observe fuel pressure gauge reading. See FUEL PUMP PRESSURE  table. If fuel pressure reading is within specification, go to next step. If fuel pressure reading is not within specification, perform fuel system diagnosis. See appropriate BASIC DIAGNOSTIC PROCEDURES article.
  6. Turn fuel pump off. Observe fuel pressure gauge. If fuel pressure remains constant, go to next step. If fuel system does not remain constant, perform fuel system diagnosis. See appropriate BASIC DIAGNOSTIC PROCEDURES article.
    7. NOTE: Perform step 7)  on each injector.
  7. Disconnect fuel injectors harness connector. Using appropriate fuel injector adapter, connect Fuel Injector Tester (J-39021) to fuel injector. Connect fuel injector tester power leads to appropriate battery terminals. Set amperage supply selector switch on fuel injector tester to Balance Test 2.5-amp position. Turn ignition on, and then off. Record fuel pressure reading (first reading). Energize injector by depressing PUSH TO START TEST button on injector tester and hold until fuel pressure gauge stabilizes. Record fuel pressure reading (second reading). Subtract first reading from second reading (this result is pressure drop value). Add pressure drop value for each injector together and divide total by total number of injectors. If any injector's drop value is greater or less than average drop value by 1.5 psi, replace faulty injector(s) as necessary. If no injector's drop value is greater or less than average drop value by 1.5 psi, repair by symptom. See appropriate TROUBLE SHOOTING - NO CODES article.
FUEL PUMP PRESSURE

Application (1)KOEO psi (kg/cm2 )
1.0L 23-31 (1.6-2.2)
1.3L 39-44 (2.7-3.1)
1.8L 44-50 (3.1-3.5)
1.9L 40-55 (2.8-3.9)
2.2L, 3.1L & 3.5L 41-47 (2.9-3.3)
2.4L
With EGR 41-47 (2.9-3.3)
Without EGR 52-58 (3.7-4.1)
3.0L 40-48 (2.8-3.4)
3.8L, 4.0L & 4.6L 48-55 (3.4-3.9)
5.7L 55-60 (3.9-4.2)
(1) KOEO is ignition ON and engine OFF.
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