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 approximately 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 above 20°C (68°F) and below 55°C (131°F). The engine control system should be in OPEN LOOP mode, and the engine speed is below 1900 rpm. When the vehicle is started and the coolant temperature is below 20°C (68°F), the air will be diverted to the atmosphere for the entire key cycle.

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 coolant temperature is between 20°C and 55°C (68°F and 131°F), and the engine control system is in OPEN LOOP mode. 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

1. Fuse number 7 is located in the relay convenience center.
2. Removing the diverter/silencer allows for easy access to determine if air is being diverted to the atmosphere.