Warm Dr-5 - EGR System Check
- With engine at normal operating temperature, let engine idle for one minute. While observing EGR valve stem, raise engine speed to more than 2500 RPM for more than 5 seconds. As engine speed increases, EGR valve stem should move upward. If EGR valve stem moves upward, go to next step. If EGR valve stem does not move, go to step 4).
- Connect a tachometer to engine. Disconnect EGR vacuum line. Connect a vacuum pump to EGR valve. Slowly apply vacuum to EGR valve. Engine speed should decrease with 3-5 in. Hg vacuum applied and continue to drop as more vacuum is applied to EGR valve. If engine speed decreases, on 4-Bbl. models, go to WARM DR-6 , on 2-Bbl. models, go to next step. If engine speed does not decrease until 5 in. Hg vacuum or more is applied to EGR valve, replace EGR valve.
- With engine running, disconnect manifold vacuum line from vacuum bleed-off valve and plug hose. Connect a vacuum pump to bleed-off valve nipple. Apply 25 in. Hg vacuum. Raise engine speed to 2500 RPM for 5 seconds. As engine speed is increased, EGR valve stem should not move. If EGR valve stem does not move, go to WARM DR-6 . If EGR valve stem moves upward, replace vacuum bleed-off valve.
- Disconnect vacuum hose from EGR valve. Connect a vacuum gauge to EGR vacuum hose. Raise engine speed to 2500 RPM for 5 seconds. As engine speed is increased, vacuum gauge reading should increase. If vacuum gauge reading increases, replace EGR valve. If vacuum gauge reading does not increase, on 2-Bbl. models, go to next step, on 4-Bbl. models go to step 7).
- Disconnect EGR signal hose from vacuum bleed-off valve. Plug vacuum hose. Reconnect vacuum hose to EGR valve. Raise engine speed to 2500 RPM for 5 seconds. As engine speed is increased, EGR valve stem should move upward. If EGR valve stem moves upward, replace vacuum bleed-off valve. If EGR valve stem does not move upward, on California models, go to step 7), on Federal models, go to next step.
- Disconnect vacuum hose from White side of EGR vacuum delay valve. Connect a vacuum gauge to vacuum delay valve vacuum hose. Raise engine speed to 2500 RPM. As engine speed is increased, reading on vacuum gauge should increase. If vacuum gauge reading increased, replace EGR vacuum delay valve. If vacuum gauge reading did not increase, go to next step.
- Disconnect bottom hose from EGR vacuum solenoid. Connect a vacuum gauge to EGR vacuum solenoid. Raise engine speed to 2500 RPM. As engine speed is increased, reading on vacuum gauge should increase. If vacuum gauge reading increases, repair vacuum hose to EGR valve. If vacuum gauge reading did not increase, go to next step.
- Remove top hose from EGR vacuum solenoid. Connect a vacuum gauge to EGR vacuum solenoid. Raise engine speed to 2500 RPM. As engine speed is increased, reading on vacuum gauge should increase. If vacuum gauge reading increases, go to step 11). If vacuum gauge reading does not increase, on 2-Bbl. models, repair vacuum supply from carburetor, on 4-Bbl. models, go to next step.
- Disconnect vacuum hose connector from EGR amplifier. Connect a vacuum gauge to middle vacuum hose on connector. Slowly increase engine speed. As engine speed increases, vacuum gauge reading should increase. If vacuum gauge reading increased, go to next step. If vacuum gauge reading does not increase, repair vacuum supply from carburetor.
- Connect a vacuum gauge to top vacuum hose on EGR amplifier vacuum hose connector. Vacuum gauge should read manifold vacuum. If vacuum gauge reading is okay, replace EGR amplifier. If vacuum gauge reading is not okay, repair vacuum supply from intake manifold.
- Connect voltmeter to Gray wire of EGR vacuum solenoid and ground. Voltmeter should read within one volt of battery voltage. If voltage reading is okay, replace vacuum solenoid assembly. If voltage reading is 0-1 volt, go to next step.
- Turn engine off. Disconnect computer 12-pin connector. Turn ignition switch to "RUN" position. Voltmeter reading should be within one volt of battery voltage. If voltmeter reading is okay, replace computer. If voltmeter reading is still 0-1 volt, repair Gray wire for a short to ground.