EGR System Operation
- Place transmission in Neutral and set parking brake. Start engine and allow engine to reach normal operating temperature. Quickly accelerate engine to approximately 2, 000 RPM while watching EGR valve stem. Stem should move when engine is accelerated. If not, refer to TROUBLE SHOOTING in this article.
- Once EGR valve movement has been obtained, it is necessary to determine if EGR is actually taking place. Disconnect vacuum hose at EGR valve. Using a length of vacuum hose and an external vacuum source, apply 10 in. Hg or greater vacuum to EGR valve while engine is idling. Engine idle speed should drop a minimum of 150 RPM or stall. This indicates EGR is flowing properly.
- If speed does not change or change is less than minimum, exhaust deposits are in EGR valve or intake manifold passages. Remove valve for inspection and cleaning. Inspect manifold passages and clean as required.
NOTE:
When cleaning valve, do not allow cleaning solvents on diaphragm. Do not push on diaphragm to operate valve, use vacuum only.