EGR Function Testing - Hyundai Hyundai Elantra I

1986-87 (Dual EGR Valves)

1. With engine cold, start engine and allow to idle. Observe sub-EGR valve and ensure it does not operate as engine speed is increased to 2500 RPM. If sub-EGR valve operates, thermovalve is defective.
2. Allow engine to warm to normal operating temperature. Observe sub-EGR valve and ensure it operates as engine speed is increased to 2500 RPM. If sub-EGR valve does not operate, sub-EGR valve or thermovalve is defective.
3. Disconnect Green-striped vacuum hose from carburetor nipple and attach a vacuum pump to hose. Manually pull on linkage of sub-EGR valve, and at same time apply 6 in. Hg. If idle becomes rough, main EGR valve is functioning properly.
4. Connect a vacuum gauge to directly to carburetor nipple. Increase engine speed to about 3000 RPM. If vacuum is shown on gauge, system is functioning properly.

1988-89 Carbureted Models (Ported EGR Valve)

1. Disconnect Green-striped hose from carburetor. Plug carburetor nipple. Connect a hand-held vacuum pump to disconnected vacuum hose. With engine coolant temperature at 113°F (45°C) or less, raise engine speed to 3500 RPM. Apply vacuum. Vacuum should bleed down.
2. With engine coolant temperature at 185°F (85°C) or more and engine at idle, apply vacuum. Vacuum should bleed down. Raise engine speed to 3500 RPM. Apply vacuum. Vacuum should bleed down to about 3.2 in. Hg, then hold.
3. Reconnect Green-striped hose to carburetor. Disconnect vacuum hose from EGR valve and connect vacuum pump to EGR valve. With engine idling, apply vacuum. If vacuum holds and idle becomes unstable or engine stalls, EGR system is functioning properly.

1988-99 Fuel Injected Models (Ported EGR Valve)

1. Disconnect Green-striped vacuum hose from throttle body and connect vacuum pump to hose end. Plug throttle body nipple. With engine temperature at 140°F (60°C) or less and engine idling, apply vacuum to hose. If idle speed does not change and vacuum leaks down from EGR solenoid, system is functioning properly.
2. With engine temperature at 185-205°F (85-95°C) and engine idling, apply 2 in. Hg to hose. If idle does not change, and vacuum holds, system is functioning properly.
3. Apply 6.8 in. Hg. If vacuum holds and idle becomes unstable or engine stalls, EGR system is functioning properly.

Sonata

Remove EGR valve and inspect for carbon deposits. Ensure valve is not sticking. Apply vacuum to valve and check for leaking diaphragm. Check air flow through valve with vacuum applied.

TEST 5

For EGR function testing, see appropriate ENGINE PERFORMANCE section of electronic information product.