Air Injection: Testing and Inspection

AIR PUMP

TEST DESCRIPTION:

1. Remove the hose from A.I.R. Injection Manifold Check Valve prior to starting the engine. Start engine and accelerate to approximatley 1500 rpm and observe air flow from hose. If air flow increases as the engine speed increases, the air pump is OK. If not proceed as follows:
2. Check to make sure air pump is not seized.
3. Check for proper drive belt tension.
4. Check air pump for leaking pressure relief valve. Air leakage may be heard from this valve with engine running.
5. Check hoses, tubes, and connections for proper routing and no leakage.
6. Check air injection pump for proper mounting.



CHECK VALVE

TEST DESCRIPTION:

Whenever a hose is removed from a check valve, the check valve should be inspected. Replace check valve if the hose shows signs of exhaust gas contamination. Little or no air should be felt coming from check valve with engine running at idle. Air should flow freely through the valve towards the engine cylinder head (one direction only).

Wiring Diagram for A.I.R. Control Valve:

AIR MANAGEMENT CHECK (EDV VALVE)

CIRCUIT DESCRIPTION:

An electric air control valve solenoid directs air into the exhaust ports, or to atmosphere. Air is directed into the exhaust ports whenever the engine is started and the coolant temperature is approximately above 20~C (68~F). When the vehicle is started and the coolant temperature is approximately below 20~C (68~F), the air will be directed to the atmosphere until the coolant temperature becomes higher than 20~C (68~F) and the engine control system goes into CLOSED LOOP mode. When the vehicle is moving, the air will be diverted to the atmosphere at coolant temperatures approximately above 55~C (131~F). If the ECM detects an excessive battery voltage or if a diagnostic code currently exist, air will not be directed to the exhaust ports.

Chart C-6:

TEST DESCRIPTION: The numbers below refer to circled numbers on the diagnostic chart.

1. If the EDV does not have 10" Hg (34 kPa) of vacuum applied to the valve, inspect for a pinched, plugged, or a leak in the vacuum hose. The ECM should energize the EDV at idle when the engine is at operating temperature. This will allow air to be directed to the exhaust ports. At high engine speeds, between approximately 2000-2500 rpm, the ECM will power off the EDV which will allow air to divert to the atmosphere.
2. This test checks for a grounded Electric Divert Valve (EDV) circuit. Normally, the system light will be OFF.
3. This checks for a open circuit. Grounding the diagnostic test terminal will energize the solenoid if the ECM and/or circuit is normal. If the test light is ON, the circuit is okay, and the fault is in the valve or valve connections.

NOTE: Once the test sequence is completed or after repairs, clear codes and verify NO "Service Engine Soon" light exist.



DIAGNOSTIC AIDS:

Removing the diverter/silencer allows for easy access to determine if air is being diverted to the atmosphere.