EGR Function Testing - Chrysler Trucks: Other Dodge Cab & Chassis Dakota

Ported EGR System

1. Check vacuum lines for correct routing. Warm engine to normal operating temperature. Some models with EGR delay timers must operate at least 1-2 minutes for EGR to function.
2. While watching EGR pintle, abruptly accelerate engine to 2000-3000 RPM. EGR pintle should open at least 1/8". If EGR pintle does not move, check for cracked, leaking, disconnected or plugged vacuum hose. Verify correct vacuum hose routing.
3. Connect a hand-held vacuum pump to EGR valve. Idle engine and gradually apply a minimum of 10 in. Hg. EGR valve stem should move and engine speed should drop at least 150 RPM.

Sub-EGR Control System

Check vacuum lines for correct routing. Disconnect Green-stripe vacuum hose from carburetor. Attach a vacuum pump to vacuum hose. With engine idling, manually open sub-EGR control valve. Apply 6 in. Hg to EGR valve and engine should run rough. Reconnect vacuum hoses.

Vacuum Amplifier (If Equipped)

1. Ensure manifold vacuum is present. With engine warm and at curb idle, connect vacuum gauge to hose on vacuum amplifier leading to venturi vacuum port. Attach a vacuum pump to hose, and apply 2 in. Hg.
2. Disconnect EGR delay timer hose (if equipped). EGR valve should open and engine speed should drop at least 150 RPM. If engine speed does not drop, replace vacuum amplifier.

Backpressure EGR Valve

Check vacuum hoses for correct routing. Warm engine to normal operating temperature. Raise engine speed to 2000-300 RPM. Apply about 8-10 in. Hg to EGR valve. Engine RPM should drop. If test results are as specified, system is okay. If engine RPM does not drop, but EGR valve opens, check for plugged EGR ports. If EGR valve does not open, replace EGR valve.

EGR System

1. Check vacuum hoses for correct routing. Warm engine to normal operating temperature. Engine coolant temperature must be greater than 150°F (65°C).
2. Apply parking brake. Place transmission in Neutral with throttle in idle position. Suddenly increase engine RPM to 2000-3000 RPM, while noting movement of EGR valve stem. DO NOT exceed 3000 RPM.
3. Valve stem in EGR valve should move when engine RPM is increased. Repeat test procedure several times to ensure correct operation. If valve stem does not move, check EGR system and vacuum supply.

EGR Valve Flow

1. Disconnect vacuum hose from EGR valve. Connect vacuum pump to EGR valve. Start engine and allow engine to idle. Slowly apply vacuum to EGR valve.
2. Engine idle speed should begin to decrease, or engine may stall, when applied vacuum reaches 5.0 in. Hg on RWD trucks, or 2.0-3.5 in. Hg on FWD vans. This indicates EGR valve is operating properly. If EGR valve does not operate correctly, remove EGR valve and check for restricted exhaust passages.