Air Injection: Testing and Inspection
Air Pump1. Operate engine until normal operating temperature is obtained. Check all hose fittings for leaks.
2. Check air pump for noise, if excessive, replace air pump.
3. Disconnect air hose from air pump outlet and connect a suitable air pump test gauge to air pump outlet.
4. Connect a suitable tachometer to the engine.
5. For GLC, 626 & B2000 models, increase engine speed to 1500 RPM and check gauge reading. Reading should be .57 psi for GLC & 626 models and 1 psi for B2000 models. If air pump readings are not as specified, replace air pump.
Check Valve
1. Remove check valve from engine.
2. Blow air through check valve from both ends. Air flow should be in one direction. If air flow is in two directions, replace check valve.
AIR CONTROL VALVE
Fig.35 - Checking Air Control Valve:
GLC Models
1. Disconnect vacuum hoses (1) and (2), Fig. 35, from air control valve.
2. Disconnect air hose (A) from air control valve and start engine. Ensure air flows out port (a).
3. Disconnect air hoses (B) and (C) from air control valve. Apply intake manifold vacuum to hose (2). Apply manifold vacuum to hose (1), air should flow only from port (c).
4. Remove vacuum hose (2). Apply manifold vacuum to hose (1), air should flow only from port (c).
5. Connect vacuum and air hoses. Ensure no air flows out port (a) at idle.
6. Increase engine speed to 4000 RPM and ensure air flows out port (a). If no air flow, replace air control valve.
Fig.37 - Disconnecting Vacuum Hose (B) On Air Control Valve:
626 & B2000 Models
1. Operate engine until normal operating temperature is obtained and switch engine off.
2. Disconnect air hose from air control valve. Start and operate engine at idle.
3. Disconnect vacuum hose (A) from air control valve. Air should flow out from air control valve outlet port (a).
4. Connect vacuum hose (A) to No. 1 air control relief valve. Ensure air does not flow from air control valve outlet port (a).
5. Disconnect vacuum hose (B), Fig. 37, from vacuum pipe. Disconnect vacuum hose from air control valve and connect onto a suitable "T" joint.
6. Connect a hose between No. 1 relief valve and "T" joint. Connect vacuum hose to the "T" joint so that inlet manifold vacuum can be directed to the No. 2 relief valve. Air should flow from outlet port (a) of the air control valve.
7. Disconnect and plug vacuum hose (B) from No. 2 relief valve. Ensure air does not flow from air control valve outlet port.
8. Disconnect air control valve and No. 2 check valve hose from air control valve.
9. Disconnect air switching valve and vacuum check valve hose from air control valve. Air should flow out from air control valve (b).
10. Connect air control valve vacuum hose to the air switching valve. Ensure air does not flow from air control valve outlet port (b). If air flows out air control valve outlet port (b), replace air control valve.
Reed Valve
1. Operate engine until normal operating temperature is obtained and switch engine off.
2. Disconnect air hose from reed valve. Start and operate engine at idle.
3. Position a finger over reed valve inlet and ensure air is sucked into the valve.
4. Increase engine speed to 1500 RPM and check for exhaust gas leak at air inlet fitting and on reed valve. If exhaust gas is leaking at either the air inlet fitting or reed valve, replace reed valve.
Water Thermo Switch (Some Applications)
1. Disconnect bullet connectors and remove water thermo switch from radiator lower tank.
2. Connect a suitable voltmeter to water thermo switch terminals, then place water thermo switch and a thermometer into a water beaker and heat gradually.
3. Check temperature at which there is no continuity between both terminals. Temperature should be 63° F, (17° C). If temperature is not to specification, replace water thermo switch.