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1994 Ford Mustang GT DTC codes 314

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I have a 94 mustang and it was throwing codes 311 and 314.  My Smog/Air Pump was locked so I have been running with a smaller belt and eliminated it.  I recently added a new smog pump and rerouted with a stock belt.  I Ran codes again and I am getting a 314.  Can anyone help me or point me to what I should be looking for?

 

Thanks

Verified Answer
  • Hi there.

    Sounds like you need to check the system. For example, a couple of things that can happen are debris can clog the lines or the valves can get corroded or rusted. Here is some information:

    311 - AIR system not working - Single, Right or Rear HO2S - Air Injection

    314 - AIR inoperative, Left or Front HO2S - Air Injection

     Air Pump System: By-Pass (Diverter Valve)

    Testing

    1.     Turn the ignition key OFF.
    2.     Remove the control vacuum line from the bypass valve.
    3.     Start the engine and bring it to normal operating temperature.
    4.     Check for vacuum at the vacuum line. If there is no vacuum, check the solenoid vacuum valve assembly. If vacuum is present, inspect the air bypass valve.
    5.     Turn the engine OFF and disconnect the air hose at the bypass valve outlet.
    6.     Inspect the outlet for damage from the hot exhaust gas.
    7.     If the valve is damaged, replace it. If the valve is not damaged, check the bypass valve diaphragm.
    8.     Connect a vacuum pump to the bypass valve and apply 10 in. Hg of vacuum.
    9.     If the valve holds vacuum, leave the vacuum applied and proceed to Step 10. If the valve does not hold vacuum, it must be replaced.
    10.     Start the engine and increase the engine speed to 1500 rpm.
    11.     Check for air flow at the valve outlet, either audibly or by feel. If there is air flow, proceed to Step 12. If there is no air flow, replace the air bypass valve.
    12.     Release the vacuum applied by the vacuum pump and check that the air flow switches from the valve outlet to the dump port or silencer ports, either audibly or by feel.
    13.     If the air flow does not switch, replace the air bypass valve. If the air flow switches, the air bypass valve is okay, check the air supply control valve.

     

All Replies
  • Hi there.

    Sounds like you need to check the system. For example, a couple of things that can happen are debris can clog the lines or the valves can get corroded or rusted. Here is some information:

    311 - AIR system not working - Single, Right or Rear HO2S - Air Injection

    314 - AIR inoperative, Left or Front HO2S - Air Injection

     Air Pump System: By-Pass (Diverter Valve)

    Testing

    1.     Turn the ignition key OFF.
    2.     Remove the control vacuum line from the bypass valve.
    3.     Start the engine and bring it to normal operating temperature.
    4.     Check for vacuum at the vacuum line. If there is no vacuum, check the solenoid vacuum valve assembly. If vacuum is present, inspect the air bypass valve.
    5.     Turn the engine OFF and disconnect the air hose at the bypass valve outlet.
    6.     Inspect the outlet for damage from the hot exhaust gas.
    7.     If the valve is damaged, replace it. If the valve is not damaged, check the bypass valve diaphragm.
    8.     Connect a vacuum pump to the bypass valve and apply 10 in. Hg of vacuum.
    9.     If the valve holds vacuum, leave the vacuum applied and proceed to Step 10. If the valve does not hold vacuum, it must be replaced.
    10.     Start the engine and increase the engine speed to 1500 rpm.
    11.     Check for air flow at the valve outlet, either audibly or by feel. If there is air flow, proceed to Step 12. If there is no air flow, replace the air bypass valve.
    12.     Release the vacuum applied by the vacuum pump and check that the air flow switches from the valve outlet to the dump port or silencer ports, either audibly or by feel.
    13.     If the air flow does not switch, replace the air bypass valve. If the air flow switches, the air bypass valve is okay, check the air supply control valve.