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Home >> Ford >> 1983 >> EXP Base, 1.6 2 >> Repair and Diagnosis >> Engine Performance >> System >> 1.6L EEC IV Testing >> Quick Tests >> Codes 41 & 42 - Fuel Control Circuit >> Code 42
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Code 42

  1. Disconnect wiring harness at EGO sensor. Using a jumper wire, ground the oxygen sensor wire (Dk Grn/Ppl) to the engine block. Repeat Engine Running Test portion of Quick Test. If code 41 results, proceed to step 3). If not, proceed to step 2).
  2. Check continuity from ECA connector J1 pin 5 to EGO ground (Org wire). Check continuity from ECA connector J1 pin 6 to EGO connector (Dk Grn/Ppl wire). If both circuits are less than 5 ohms, disconnect ECA connectors and inspect for damaged or corroded terminals. If connectors are good, replace ECA. If either or both circuits are above 5 ohms, repair the wiring harness.
  3. With EGO sensor disconnected, connect a digital voltmeter between the EGO sensor and ground. Run engine at 2000 RPM for 2 minutes while observing voltmeter. Disconnect manifold vacuum hose located just downstream of the throttle plate. If voltmeter reads less than 0.4-volts, EGO sensor is good, proceed to step 4). If voltmeter reads more than 0.4-volts, replace EGO sensor and retest.
  4. Connect fuel pressure gauge to fuel rail. Start and run engine. Fuel pressure should be 25-45 psi (1.76-3.16 kg/cm2 ). If engine will not start, cycle ignition key on and off several times to pressurize the fuel system. Fuel pressure should remain at 35-45 psi (2.46-3.16 kg/cm2 ) for at least 60 seconds after key is turned off. If fuel pressure is not to specifications, see FUEL INJECTION SYSTEM - MULTI-POINT .
  5. Turn ignition off. Disconnect electrical connectors at injectors 2, 3, and 4. Set DVOM on 20 ohm range and measure resistance between pins 3 and 11 of ECA plug J2 (injector 1). Record reading. Disconnect electrical connector at injector 1 and reconnect connector at injector 2. Measure resistance between same pins again. Record reading. Disconnect electrical connector at injector 2 and reconnect connector at injector 3. Measure resistance between pins 4 and 11 of plug J2. Record reading.
  6. Disconnect electrical connector at injector 3 and reconnect connector at injector 4. Measure resistance between same pins again. Record reading. If all 4 readings are not 2.0-3.5 ohms, check wiring harness on injector(s) and repair as required. If wiring harness(es) is okay, replace injector(s). If all 4 readings are correct, circuits are okay. Continue test.
  7. Connect a non-powered 12-volt test lamp between pins 11 and 3 of ECA plug J2. Crank engine and note results. Then connect test lamp between pins 11 and 4 of ECA plug J2. If test lamp does not glow on 1 or both tests, verify that battery voltage is recorded at pin 11 of plug J2.
  8. If voltage is not present, repair wire or replace battery. If voltage is present, replace ECA. If test lamp glows brightly on 1 or both tests, check circuits 95 (Tan wire with Purple dot) and 96 (Tan wire with Orange dot) to injectors. If no problem is found replace ECA. If test lamp glows dimly on both tests, circuits are okay. Continue test.
  9. Connect a tachometer to engine. Raise engine speed to 2000 RPM and maintain. (May be necessary to disconnect ISC and use throttle body stop screw to maintain speed.) Disconnect and reconnect injectors one at a time. Note RPM drop for each injector. Reconnect ISC and reset curb idle. If all injectors produce an RPM drop of about 150 RPM, injectors are operating properly. If not, replace suspect injector.
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