California
SYSTEM TESTNOTE: When disconnecting the vacuum hoses, mark or label them to ensure proper routing when reconnecting.
Testing The EGR System Using A Vacuum Tee:
COLD ENGINE TEST - Coolant temperature is below 20°C (68°F)
1. Disconnect the green striped vacuum hose from the EGR Valve.
2. Using a three-way terminal and vacuum hose, connect a hand vacuum pump into the EGR valve line.
At this point, do not apply vacuum.
3. Quickly depress the accelerator pedal to race the engine.
No change in vacuum (atmospheric pressure) should be indicated on the gauge.
WARM ENGINE TEST - Coolant temperature is above 70°C (158°F)
1. Disconnect the green striped vacuum hose from the EGR Valve.
2. Using a three-way terminal and vacuum hose, connect a hand vacuum pump into the EGR valve line.
At this point, do not apply vacuum.
3. Again quickly depress the accelerator pedal to race the engine. Vacuum should rise temporarily to 3.9" or more.
Testing The Operation Of The EGR System:
4. Remove the three-way terminal and connect the vacuum pump directly to the EGR valve.
5. Check to see that the engine stalls or the idle is unstable when a vacuum of 8.5" is applied.
If there is no change in the engine rpm, it is possible that the passages or the valve may need to be cleaned.
Refer to MAINTENANCE PROCEDURES for EGR SYSTEM cleaning.
EGR CONTROL VACUUM SUPPLY
Testing The EGR Vacuum Supply:
1. Disconnect the vacuum hose from the throttle body EGR vacuum nipple and connect a hand vacuum pump or gauge to the nipple.
2. Start the engine. Gradually increase the engine rpm. Vacuum from the EGR nipple should increase proportionately with the engine rpm.
NOTE: If vacuum cannot be measured or does not change with the engine rpm, ensure that the hose is connected to the proper port. If so, the EGR port may be plugged and should be cleaned.
EGR SOLENOID
Testing The EGR Control Solenoid Valve:
1. Disconnect the yellow striped vacuum hose and the green striped vacuum hose from the solenoid valve.
2. Disconnect the electrical harness connector.
3. Connect a hand vacuum pump to the nipple which the green striped hose was connected to.
4. Connect jumper leads to the solenoid terminals.
EGR Control Solenoid Valve Voltage Test:
5. While applying vacuum to the solenoid, apply battery voltage directly to the solenoid terminals.
Vacuum should HOLD.
6. Discontinue voltage. Vacuum should LEAK.
EGR Control Solenoid Valve Resistance Check:
7. Measure the resistance between the terminals of the solenoid valve.
Refer to ELECTRICAL SPECIFICATIONS
EGR TEMPERATURE SENSOR TEST
EGR Temperature Sensor Test:
1. Remove the EGR Temperature Sensor.
2. Place the sensor in 50°C (122°F) water.
3. Measure the resistance between the terminals.
Refer to ELECTRICAL SPECIFICATIONS.
4. Increase the temperature of the water to 100°C (212°F).
5. Measure the resistance between the terminals. Refer to ELECTRICAL SPECIFICATIONS.
If there is a significant deviation from the standard value, replace the EGR Temperature sensor.
EGR VALVE TESTING
EGR Valve Test:
1. Remove the EGR valve and check it for sticking or carbon deposits.
If such condition exists, refer to MAINTENANCE PROCEDURES for EGR Control Valve and Passages cleaning.
2. Connect a hand vacuum pump to the EGR vacuum nipple.
If there is more than one nipple, the second nipple will need to be plugged for this test.
3. Apply 19.8" vacuum to the vacuum chamber of the EGR valve.
Vacuum should NOT leak. Release vacuum.
4. Apply 1.8" of vacuum. Blow air in from one side of the valve.
Air should NOT pass through.
5. Increase vacuum to 8.5" while blowing air through EGR passage.
Air should pass through.