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HOMESERVICE MANUALSFORD1984RV CUTAWAY 5.8 GREPAIR AND DIAGNOSISENGINE PERFORMANCETESTING & DIAGNOSIS5.0L/5.8L EEC IV TESTINGCIRCUIT TESTINGTEST M - AIR MANAGEMENT SYSTEM
1984 Ford RV Cutaway 5.8 G

Test M - Air Management System

1984 Ford RV Cutaway 5.8 GSECTION Test M - Air Management System
  1. Codes 44, 45 and 46. Ensure correct vacuum hose routing to TAB/TAD solenoids and by-pass diverter valve. Check for disconnected vacuum lines. Check for kinked or blocked air and vacuum hoses. Repair as required and repeat QUICK TEST  . If hoses are okay and code 44 is still present, go to step 4). If code 45 is still present, go to next step. If code 46 is still present, go to step 3).
  2. Code 45. Disconnect and plug vacuum line at diverter valve. Turn ignition off and wait 10 seconds. Repeat KEY ON-ENGINE RUNNING (KOER) SELF-TEST  and record codes. If code 45, EEC system is operating properly for code 45. If no code 45, go to step 4).
  3. Code 46. Disconnect and plug vacuum line at by-pass valve. Turn ignition off and wait 10 seconds. Repeat KEY ON-ENGINE RUNNING (KOER) SELF-TEST  and record codes. If code 46, EEC system is operating properly for code 46. If no code 46, go to next step.
  4. Turn ignition off and wait 10 seconds. With DVOM on 200 ohm scale, disconnect TAB solenoid connector and measure solenoid resistance. Disconnect TAD solenoid connector and measure solenoid resistance. If both readings are 50-100 ohms, reconnect solenoids and go to next step. If either reading is less than 50 ohms or more than 100 ohms, replace solenoid and repeat QUICK TEST  .
  5. Turn ignition off and wait 10 seconds. Enter Output State Check. Perform KEY ON-ENGINE OFF (KOEO) SELF-TEST  until end of Continuous code display. DVOM will indicate 0 volts. Depress and release throttle. If DVOM indicated high voltage, remain in Output State Check and go to next step. If DVOM did not indicate high voltage, depress throttle to wide open position and release. If voltage still does not go high, go to TEST D  step 13).
  6. Remain in Output State Check and place DVOM on 20 volt scale. Connect positive lead to vehicle power circuit on TAB solenoid and negative lead to TAB solenoid output circuit. While observing DVOM, depress and release throttle several times to cycle output on and off. Repeat sequence for TAD solenoid. If both solenoids cycle on and off, continue to next step. If either does not cycle on and off, go to step 10).
  7. Remove vacuum lines from TAB solenoid. Connect vacuum pump to TAB solenoid vacuum supply port and vacuum gauge to output port. Apply vacuum and while depressing and releasing throttle to cycle output on and off, observe vacuum gauge. Repeat sequence for TAD solenoid. If both solenoids cycle on and off, go to next step. If either solenoid does not cycle on and off, replace TAB/TAD solenoid assembly and repeat QUICK TEST  . Exit Output State Check.
  8. Disconnect TAB solenoid-to-thermactor valve vacuum hose. Ensure vacuum hose is not blocked, cracked or kinked by using vacuum gauge and pump. Repeat sequence for TAD solenoid-to-thermactor valve vacuum hose. If vacuum hoses are okay, go to next step. If not, repair as required and repeat QUICK TEST  .
  9. With vacuum hoses disconnected at TAB/TAD solenoid assembly, start engine and check for vacuum. If vacuum is present, EEC system is operating properly. Service thermactor valve or air pump. If no vacuum present, service as required and repeat QUICK TEST  .
  10. Turn ignition on (engine off). With DVOM on 20 volt scale, connect positive lead to vehicle power circuit of TAB solenoid and negative lead to good ground. Measure and record voltage. Repeat sequence for TAD solenoid. If both readings are more than 10.5 volts, go to next step. If either reading is less than 10.5 volts, repair open circuit in harness and repeat QUICK TEST  .
  11. Turn ignition off and wait 10 seconds. Disconnect 60-pin connector at ECA and connect breakout box. Leave ECA disconnected. Disconnect TAB/TAD solenoid connector. With DVOM on 200 ohm scale, measure continuity from box pin 51 to TAB circuit of TAB solenoid harness. Measure continuity from box pin 11 to TAD circuit of TAD solenoid. If readings are less than 5 ohms, go to next step. If either reading is 5 ohms or more, repair open circuit and repeat QUICK TEST  .
  12. Turn ignition off and wait 10 seconds. Breakout box connected and ECA and TAB/TAD solenoids disconnected. With DVOM on 200,000 ohm scale, measure resistance from box pin 51 to pins 37 and 57. Then measure from box pin 11 to same pins. If reading is 10,000 ohms or more, go to next step. If reading is less than 10,000 ohms, repair short to power and repeat QUICK TEST  .
  13. Turn ignition off and wait 10 seconds. Breakout box connected and ECA and TAB/TAD solenoids disconnected. With DVOM on 200,000 ohm scale, measure resistance from box pin 51 to pins 40, 46 and 60 in turn. Then measure from box pin 11 to same pins. If reading is less than 10,000 ohms, repair short to ground and repeat QUICK TEST  . If reading is 10,000 ohms or more, replace ECA and repeat QUICK TEST  .
Fig 1: Air Management Circuit
G9395
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
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  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.