Thunderbird L4-140 2.3L SOHC Turbo (1984)
Air Pump: Testing and Inspection
Note:
Engine tune up should be checked whenever the air pump system seems to be malfunctioning, especially items affecting air/fuel ratio.
Air Pump
1.
Remove air cleaner, then inspect all hoses and hose connections for leaks. Correct as necessary. Check belt tension and correct as necessary.
2.
With transmission in Park or Neutral with parking brake applied, start engine and allow it to reach normal operating temperature.
3.
Stop engine. Disconnect air supply hose(s) from air pump to air bypass valve.
4.
Install suitable thermactor test gauge in end of hose disconnected from bypass valve. Secure hose with clamp to prevent it from blowing out. On
side or cover mounted bypass valves, install an elbow and hose adapter, then install test gauge. Position air pump supply tester so that air blast
emitted will be harmlessly dissipated.
5.
Connect tachometer to engine and start engine. Slowly increase engine speed to 1000 RPM while observing pressure at gauge. Air pump pressure
should be at least 2.25 psi. If thermactor test gauge is not used, increase engine speed to 1500 RPM and place hand over open hose. Air flow
should be heard and felt.
6.
If air pump output pressure is not at least 2.25 psi, or if air flow is not heard and felt, replace pump and repeat test.
Air Manifold, Hose and Tube
1.
Inspect all hoses and tubes for deterioration or cracks.
2.
Check hose and tube routing as interference may cause wear.
3.
Check all hose and tube connections.
4.
Check the pressure side of the system for leaks with a soapy water solution. With the pump running, bubbles will form if a leak exists.
5.
When replacing any hose or tube, note routing before removal. The hoses used with this system are made of special material to withstand high
temperature. No other type should be used.
Exhaust Check Valves
1.
Check valves should be inspected whenever the hose is disconnected from the valve or check valve failure is suspected. Any indication of exhaust
gases in the air pump indicates check valve failure.
2.
Orally blow through the check valve (toward air manifold) then attempt to suck back. Flow should be toward air manifold only.
3.
When replacing a check valve, be careful not to bend or twist the air manifold.
