Exhaust Gas Recirculation (Port Fuel Injection)

Chart C-7A - EGR Check:

Wiring Diagram for EGR Check:

CHART C-7A EXHAUST GAS RECIRCULATION (EGR) CHECK




Circuit Description:

The EGR valve is opened by manifold vacuum, to let exhaust gas flow into the intake manifold. The exhaust gas then moves with the air/fuel mixture into the combustion chamber. If too much exhaust gas enters, combustion will not occur. For this reason, very little exhaust gas is allowed to pass through the valve, especially at idle. The EGR valve is usually open when the engine is warm and above idle speed. The amount of exhaust gas recirculated is controlled by variations in vacuum and the EGR vacuum control solenoid.


Test Description: Numbers below refer to circled numbers on the diagnostic chart.


1. Checks for a sticking EGR valve. If sticking, remove and examine valve to determine whether it can be cleaned, or must replaced. A sticking EGR valve will most likely cause a rough idle condition.


2. Checks for plugged EGR passages. If passages are plugged, the engine may have severe detonation on acceleration.