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Home >> Nissan-Datsun >> 1978 >> 200SX Standard Trans >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Fuel Shut-Off System >> Testing >> Fuel Shut-Off System >> 1978 Models
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1978 Models

  1. With engine idling at normal operating temperature, disconnect anti-dieseling solenoid valve. Engine should stall. If not, replace solenoid assembly.
  2. Connect anti-dieseling solenoid wire directly to positive battery terminal. On B210, go to next step. On Pickups, go to step  5).
  3. Connect voltmeter to terminals "A" and "B" of function test connector. See Fig 1. Depress clutch pedal and shift into high gear (Neutral on Auto. Trans.).
  4. Increase engine speed to 3000 RPM, release throttle, and check voltage across terminals. If voltage is zero (0) during acceleration, and 12 volts during deceleration, fuel shut-off system is working properly.
  5. Connect voltmeter to anti-dieseling solenoid harness and ground. Disconnect clutch pedal switch. Depress clutch pedal and shift into high gear (Neutral on Auto. Trans.).
  6. Bring engine speed to 2500-3000 RPM and quickly release throttle. If voltmeter needle deflects from 12 to zero (0) volts, electrical circuit is working properly. If there is no deflection, either fuel shut-off vacuum switch or Neutral switch are not working properly.
  7. To determine defective part, reconnect clutch pedal switch. Disconnect fuel shut-off vacuum switch connector. Connect ohmmeter to fuel shut-off vacuum switch. See Figure.
    Fig 1: 1978 B210 Fuel Shut-Off System Test
    G09313114Courtesy of NISSAN NORTH AMERICA, INC.
  8. Raise engine speed to 2500-3000 RPM, quickly release throttle, and check continuity between terminals "A" and "B", and between terminals "A" and "C".
  9. Fuel shut-off vacuum switch is working properly if polarity is reversed between terminals "A" and "B" and between "A" and "C". If not, vacuum switch is defective and should be replaced.
  10. If all test are okay, repeat step  5). If voltmeter does not deflect from 12 volts to zero (0) volts, replace Neutral switch.
  11. To check inhibitor relay (Auto. Trans.), apply 12 volts across terminals No. 1 and 4. See Figure. Make sure continuity exists between terminals No. 2 and 3. With no voltage applied, check that no continuity exists between terminals No. 2 and 3. If not, replace relay.
  12. On B210, disconnect throttle valve switch. Connect continuity tester to throttle valve switch connector. Start engine, increase engine speed slowly, and check speed at which throttle valve switch is turned on.
  13. Decrease engine speed slowly and check speed at which throttle valve switch is turned off. See THROTTLE VALVE SWITCH SPECIFICATIONS  table.
THROTTLE VALVE SWITCH SPECIFICATIONS

Engine Operation Throttle Valve Switch Engine RPM
Increase On 950-1350
Decrease Off 800-1200
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