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1993 Jeep Cherokee

1990-95 ENGINE PERFORMANCE Jeep EGR Function Testing

All Models



  1. Check vacuum hoses for correct routing. Warm engine to
    normal operating temperature. Set engine speed to fast idle (or high
    enough to obtain 5 in Hg at EGR valve). Protect finger from heat and
    place finger beneath EGR valve so diaphragm movement can be felt.

  2. Disconnect vacuum hose from EGR valve. Diaphragm should
    move downward (valve closed) and increase in engine RPM should be
    noticed. Reconnect vacuum hose to EGR valve. Diaphragm should move
    upward (valve open) and engine speed should decrease by at least 150

  3. If EGR diaphragm does not move during the test, check for
    vacuum at hose. If vacuum is present, replace EGR valve. If vacuum is
    not present, check for leaking vacuum hose or plugged carburetor port.
    If EGR diaphragm moves during the test, but RPM does not change, check
    for plugged EGR port or passages.