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Test R - Fuel Control

  1. Code 41 Displayed. If engine ran for more than 2 minutes before performing Engine Running Self-Test, go to next step. If engine did not run for more than 2 minutes, prepare vehicle and perform Engine Running Self-Test.
  2. Turn key OFF. Reconnect ECA and EGO (oxygen) sensor. Disconnect thermactor and cap air supply hose at air pump. Perform Engine Running Self-Test. Because thermactor hose is disconnected, code 11 does not indicate a pass. Treat code 11 as code 44. If code 41 is present, leave thermactor hose disconnected and go to next step. If code 44 is present, perform Engine Running Self-Test.
  3. Turn key OFF and wait 10 seconds. With thermactor hose disconnected, disconnect harness at feedback control solenoid (FCS). Perform Engine Running Self-Test. If no code 41, go to step 5). If code 41, go to next step. Ignore all other codes at this time.
  4. Turn key OFF and wait 10 seconds. With FCS and thermactor hose disconnected, start and run engine at part throttle for 2 minutes. Turn key OFF and wait 10 seconds. Perform Engine Running Self-Test while holding choke 3/4 closed. DO NOT  stall engine. If code 41, reconnect all disconnected components and go to step 6). If no code 41, replace FCS and repeat Engine Running Self-Test. If code 41 still present, service carburetor.
  5. Turn key OFF and wait 10 seconds. Reconnect thermactor hose. Leave FCS solenoid disconnected. Disconnect 60-pin connector at ECA and inspect. Connect breakout box and leave ECA disconnected. With DVOM on 200,000 ohm scale, measure resistance from test pin 58 to pins 20, 40 and 46 in turn. If any less than 10,000 ohms, repair short circuit and repeat QUICK TEST. If all readings 10,000 ohms or more, replace ECA and repeat QUICK TEST.
  6. Turn key OFF. With EGO sensor disconnected, start and run engine for 2 minutes. Place DVOM on 20 volt scale. With engine running, hold choke 3/4 closed and measure voltage from EGO sensor pigtail terminal to battery negative terminal. DO NOT  stall engine. If less than .45 volt, replace EGO sensor and repeat QUICK TEST. If .45 volt or more, go to next step.
  7. Turn key OFF and wait 10 seconds. Disconnect EGO sensor. Disconnect 60-pin connector at ECA and inspect. Connect breakout box and leave ECA disconnected. With DVOM on 200 ohm scale, measure resistance from EGO sensor circuit of EGO sensor harness connector to test pin 29. Then measure from test pin 49 to pins 40 and 60. If all readings less than 5 ohms, go to next step. If any 5 ohms or more, replace ECA and repeat QUICK TEST.
  8. Turn key OFF and wait 10 seconds. With thermactor and FCS connected, disconnect harness at EGO sensor. With DVOM on 200,000 ohm scale, measure resistance from EGO sensor circuit of EGO sensor harness connector to battery negative terminal. If less than 10,000 ohms, repair short circuit and repeat QUICK TEST. If 10,000 ohms or more, replace ECA and repeat QUICK TEST.
  9. Codes 42/47 Displayed. If choke functions properly without sticking or binding, go to next step. If not, service choke assembly and repeat QUICK TEST.
  10. Start and run engine at part throttle for 2 minutes. Turn key OFF and wait 10 seconds. Disconnect harness at EGO sensor and jumper EGO sensor circuit of EGO sensor harness connector to ground. Perform Engine Running Self-Test. If code 41, go to next step. If no code 41, go to step 16). Ignore all other codes.
  11. Turn key OFF and wait 10 seconds. Disconnect 7/32" vacuum line at intake manifold vacuum tree. Set DVOM to 20V Scale. Disconnect EGO sensor from harness. Connect DVOM from EGO sensor to engine ground. Run engine at 2000 RPM for 2 minutes while observing DVOM. If less than .4V, go to next step. If not, replace EGO sensor and repeat QUICK TEST.
  12. Turn key OFF and wait 10 seconds. Reconnect vacuum hose at intake manifold vacuum tree. Disconnect FCS and place DVOM on 200 ohm scale. Measure resistance between terminals on FCS. If resistance is 15-30 ohms (2150) or 30-60 ohms (YFA), reconnect FCS and go to next step. If not resistance registers other than specified, replace FCS and repeat QUICK TEST.
  13. Turn key OFF and wait 10 seconds. Deactivate QUICK TEST and disconnect harness at FCS. With DVOM on 20 volt scale, turn ignition on. Measure voltage from voltage power circuit of FCS harness connector to battery negative terminal. If less than 10 volts, reconnect FCS, repair open circuit and repeat QUICK TEST. If 10 volts or more, go to next step.
  14. Turn key OFF and wait 10 seconds. Disconnect 60-pin connector at ECA and inspect. Connect breakout box and leave ECA disconnected. Disconnect EGO sensor harness. With DVOM on 200,000 ohm scale, leave FCS solenoid disconnected, measure resistance between test pin 58 and pin 37. If less than 10,000 ohms, repair short circuit and repeat QUICK TEST. If 10,000 ohms or more, go to next step.
  15. Turn key OFF and wait 10 seconds. Disconnect harness at FCS. Disconnect 60-pin connector at ECA and inspect. Connect breakout box and leave ECA disconnected. With DVOM on 200 ohm scale, measure resistance from feedback circuit of FCS harness to test pin 58. If less than 5 ohms, replace ECA and repeat QUICK TEST. If 5 ohms or more, repair open circuit and repeat QUICK TEST.
  16. Turn key OFF and wait 10 seconds. Disconnect vacuum hose between canister purge solenoid and canister, plug both ends. Repeat Engine Running Self-Test. If code 42, go to next step. If not, go to TEST N.
  17. Turn key OFF and wait 10 seconds. Connect breakout box. Measure resistance between test pin 49 and EGO sensor ground at engine block. Measure resistance between test pin 29 and EGO sensor harness connector. If both circuits are less than 5 ohms, disconnect ECA and check for damage or corrosion. If there is no damage or corrosion, replace ECA and repeat QUICK TEST. If resistance is greater than 5 ohms, add a larger ohm resistor to the harness circuit and repeat QUICK TEST.
  18. Code 43 Displayed. Start and run engine at 2000 RPM for 2 minutes. Perform Engine Running Self-Test. If code 43, go to next step. If no code 43, service other codes as necessary.
  19. If there are any leaks at intake manifold or inlet pipe, repair as required and repeat QUICK TEST. If okay, go to next step.
  20. Start engine and allow to idle. If idle quality weakens and remains poor during and after QUICK TEST, service carburetor. If not, replace EGO sensor and repeat QUICK TEST.
Fig 1: FBC Fuel Control Circuits
G2559
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