Air Injection System Toyota Land Cruiser 60

DESCRIPTION

Air injection system is used to reduce hydrocarbon (HC) and carbon monoxide (CO) emissions. Fresh air is injected at exhaust ports, allowing exhaust gases to continue burning as they exit through the exhaust system. An air pump provides fresh air under pressure to be injected in exhaust ports. A computer control system determines when the air should be injected.

Components include air cleaner, air pump, air control valve (ACV), air by-pass valve (ABV), air switching valve (ASV), 2 check valves, relief valve, 2 vacuum switching valves (VSV), oxidation catalyst (OC), OC thermo sensor, speed sensor, vacuum transmitting valve (VTV), vacuum switch and computer.

OPERATION

The injection of fresh air is delivered at the exhaust ports, the exhaust pipe, or the air cleaner; depending on engine and vehicle operating characteristics. Air is injected at exhaust ports when intake manifold vacuum is below 13.97 in. Hg, engine speed is below 1800 RPM, vehicle speed is under 35 MPH and OC temperature is below 1112°F (600°C).

Air is by-passed to air cleaner during deceleration and/or when intake manifold vacuum is below 13.97 in. Hg, engine speed is below 1800 RPM, and OC temperature is above 1445°F (785°C). Air is injected into exhaust pipe (ahead of OC) at all other times.

AIR PUMP

1. Check air pump for abnormal noise. Check discharge pressure by connecting Air Pump Tester (09258-14010) to hose at the pump outlet. Select and use a specified orifice .217" (5.5 mm) on the tester.
2. Start engine and set engine speed at 1200 RPM. Tester gauge should read in Green zone. If tester indicates in Red zone, replace pump assembly. Remove tester and reconnect hose.

Scheme 11

1. Check operation of air by-pass valve (ABV). Disconnect air hose between ABV and exhaust pipe at ABV. Disconnect vacuum hose between ABV and No. 2 VSV at ABV and plug ABV port. With engine idling, disconnect and reconnect vacuum hose between ABV and vacuum pipe at ABV. (Scheme 11) Compressed air should momentarily escape from ABV. Reconnect air hose to ABV. (Scheme 11): Checking Operation of Air By-Pass Valve
2. Check operation of air switching valve (ASV). Disconnect air hose from check valve and vacuum hose from ASV. With engine idling, apply vacuum directly to ASV. Compressed air should escape from air hose leading to check valve.
3. Check relief valve opening pressure. Disconnect air by-pass hose from air cleaner. Connect Air Pump Tester (09258-14010) to air hose leading to check valve. Hold finger over hole on end of tester. Observe gauge on tester while gradually increasing engine speed. Opening pressure should be 5.7-8.5 psi (.40-.60 kg/cm 2 ). Remove tester and reconnect all air hoses.

VACUUM TRANSMITTING VALVE (VTV)

Remove VTV and blow through each end of valve. Air should flow easily when blowing through Blue end, and resistance should be noticed when blowing through opposite end. Replace valve if defective.

CHECK VALVES

Remove check valve and blow through both sides. Check that air does not flow from manifold side to ACV side. Check that air flows from ACV side to manifold side. Replace valve if defective.

Scheme 12

1. Disconnect electrical connector and hoses from No. 1 VSV and remove VSV. Apply battery voltage between terminals of connector. (Scheme 12) Blow into top port. Air should escape from rear port. (Scheme 12): Testing Vacuum Switching Valves Make sure battery voltage is properly applied.
2. Disconnect battery voltage and again blow into top port. Air should escape from air filter in front part of No. 1 VSV and not escape from No. 2 VSV. Replace valve if defective.
3. Using an ohmmeter, check that continuity does not exist between positive terminal of VSV connector and valve body. If continuity is present, replace valve.
4. Using an ohmmeter, measure resistance between terminals of connector. Resistance should be 38-43 ohms at 68°F (20°C). If resistance is not within specified range, replace valve.

OXIDATION CATALYST (OC) THERMO SENSOR

Unplug wiring connector for thermo sensor under driver's seat. Using an ohmmeter, measure the resistance between both terminals with engine idling. Insert ohmmeter probes from rear of connector. Resistance should be 2000-200,000 ohms. Reconnect wire connector. Check sensor wiring for damage and connector for looseness.

SPEED SENSOR

1. Block vehicle and raise 1 rear wheel off the ground. Release parking brake and place transmission in Neutral. Disconnect wiring connector from computer, located at left kick panel.
2. Using an ohmmeter, connect positive lead to rear of connector and negative lead to ground. (Scheme 13) Slowly rotate wheel. Ohmmeter needle should deflect consistently.
3. If ohmmeter does not deflect as outlined, check that speed sensor terminals at rear of speedometer are properly connected. If connection is okay, replace speedometer assembly.

Testing Speed Sensor Insert probe from rear of connector. Scheme 13

AIR PUMP BELTS

1. Check air pump belt for condition and tension. Belt tension should be 80-120 lbs. (36.3-54.4 kg) for used belt and 120-170 lbs. (54.4-77.6 kg) for new belt.
2. To adjust, loosen adjusting lever bolt and pivot bolt. Pry on rear cover of air pump in direction of belt tension. Do not pry on die-cast part of pump housing when tightening belt.

1. Check all hoses and connections. Disconnect air by-pass hose from air cleaner. Start and idle engine. With engine idling, air should not be discharged from air by-pass hose.
2. Disconnect hose from Blue side of VTV. Air should be discharged from air by-pass hose within 3-10 seconds. Reconnect hose to VTV. Discharge of air from by-pass hose should stop.
3. Disconnect air by-pass-to-exhaust pipe hose at air by-pass valve. Disconnect vacuum hose between ABV and No. 2 VSV at ABV and plug port on valve. Race engine and quickly close throttle valve. Air should be momentarily discharged from ABV. Remove plug from ABV port and reconnect hose.
4. With engine idling, connect jumper wire to back of OC thermo sensor connector. Air should be discharged from air by-pass hose. Remove jumper wire. NOTE: The following step must be performed as quickly as possible due to engine misfiring. This also tests deceleration fuel cut system.
5. Disconnect air hose from ABV. With engine idling, pinch vacuum hose leading to vacuum switch. Slowly increase engine speed to 2000 RPM. Air should be discharged from by-pass valve. Release pinched hose. Reconnect air by-pass hose to air cleaner, and hose to ABV.
6. Using a "T" connector, install vacuum gauge to hose between No. 2 VSV and ABV. Use enough hose for gauge so it can be seen from driver's seat. Perform road test. Vacuum gauge should register intake manifold vacuum at speeds below 35 MPH, and no vacuum when speed is above 50 MPH. Remove gauge and reconnect all hoses.
7. If no problem is discovered during any of these procedures, air injection system is okay. If problem is noted, check each component.