LEMON Manuals: Even more car manuals for everyone
Home >> GMC >> 1991 >> Value Van 7.4 N >> Repair and Diagnosis >> External Pages >> Different car >> Section 35 (Engine Controls - Tests W/Codes - 3.9L) >> Self-Diagnostic Tests >> Test NTC-13A - Checking EGR System

Test NTC-13A - Checking EGR System

WARNING: This page is about a different car, the 1995 Dodge Ram Wagon, 1995 Dodge Ram Van, 1995 Dodge Pickup, 1995 Dodge Dakota, and 1995 Dodge Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
  1. Using scan tool, read module information. If module information indicates vehicle is equipped with California emissions, this test does not apply, however this test can still be performed. Go to next step. If module information indicates vehicle is not equipped with California emissions, go to next step.
  2. Inspect condition of EGR hoses and routing. If EGR hoses are damaged or misrouted, repair as necessary. Perform TEST VER-2. If EGR hoses are not damaged or misrouted, go to next step.
  3. Disconnect vacuum hose from EGR solenoid. Connect vacuum gauge to disconnected vacuum hose. Start engine. If vacuum is more than 10 in. Hg at idle, go to step 5).
  4. If vacuum is less than 10 in. Hg at idle, disconnect EGR vacuum signal hose at intake manifold. Connect a vacuum gauge to intake nipple. Read vacuum gauge at idle. If vacuum is more than 10 in. Hg at idle, repair restriction or leak in vacuum hose to EGR solenoid. Perform TEST VER-2. If vacuum is less than 10 in. Hg at idle, repair plugged vacuum nipple at intake manifold. Perform TEST VER-2.
  5. Disconnect vacuum gauge. Reconnect vacuum hose to EGR solenoid. Disconnect vacuum hose from EGR valve. Connect vacuum gauge to disconnected hose. While observing vacuum gauge, momentarily snap throttle open. If vacuum is less than 5 in. Hg at any time, replace EGR valve assembly. Perform TEST VER-2. If vacuum is more than 5 in. Hg at any time, go to next step.
  6. Turn ignition off. Disconnect hose to EGR valve backpressure signal tube. Adjust a shop air hose to 20 psi (1.4 kg/cm2 ). Connect shop air to nipple on base of EGR valve. Listen for a tone change while opening and closing throttle.
  7. If tone changes, replace EGR valve. Perform TEST VER-2. If tone does not change, remove vacuum gauge. Cap open nipple at EGR valve base. Connect hand vacuum pump to EGR valve. Listen for engine RPM change while slowly applying vacuum to EGR valve. If engine RPM does not change, replace EGR valve. Perform TEST VER-2.
  8. If engine RPM changes, turn ignition off. Apply 10 in. Hg and hold for 30 seconds. If vacuum holds for 30 seconds, EGR system is functioning properly. Test is complete. If vacuum does not hold for 30 seconds, replace EGR valve. Perform TEST VER-2.
scientia non olet · About LEMON Manuals