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Home >> Saab >> 1987 >> 9000 Base, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Fuel Injection System - LH (16-Valve) >> Testing >> System Circuit Test
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System Circuit Test

  1. Remove fuel pump fuse. This will be fuse No. 30 on 900 models and fuse No. 14 on 9000 Turbo. Locate 2-pin connector for oxygen sensor preheating circuit (connector is attached to right-hand inner fender). Connect voltmeter leads across connector terminals and set to 20-volt scale. Voltmeter should read 12 volts.
    CAUTION: Engine may start and run due to residual fuel in system.
  2. If voltage reading is incorrect, perform ELECTRONIC CONTROL UNIT test. If voltage reading is correct, go to next step.
  3. Remove fuel pump fuse. This will be fuse No. 30 on 900 models and fuse No. 14 on 9000 Turbo. Attach Fuel Pump Switch Harness (83 93 886), or jumper wire, between left connection of fuse No. 30 and right connection of fuse No. 27 on 900 models. Attach Fuel Pump Switch Harness (83 93 836) between left connection of fuse No. 14 and right connection of fuse No. 22 on 9000 Turbo.
  4. Turn ignition on. If fuel system is operating properly, fuel flow through lines and injection manifold should be heard. If fuel system is not operating properly, perform FUEL PUMP DELIVERY PRESSURE test.
    NOTE: When testing injectors, leave connections intact. Test by inserting voltmeter lead through back of connector.
  5. Connect voltmeter positive lead to Blue/Red wire of injector No. 1. Connect negative lead to Green/Red wire of injector No. 1. While cranking engine, voltage reading should be 3-5 volts. Repeat test for each injector. If no reading is indicated, go to ELECTRONIC CONTROL UNIT (ECU) test.
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