EGR System

Fig. 9 Exhaust gas recirculation (EGR) system.:

Fig. 10 EGR tester:

1. With coolant temperature below 118 degrees F, connect EGR tester, Fig. 10, white wire probe to electro valve wire 146A, Fig. 9. connect EGR tester red wire probe to electro valve wire 146.

Fig. 11 EGR tester light A:

2. Start engine, then using the link rod, accelerate engine until maximum RPM is obtained and indicated by the tester, Fig. 11. This will be indicated by the EGR tester light A, remaining OFF.
3. If tester light A remains ON, check thermo switch wire 47B. If wire is satisfactory, replace thermoswitch.
4. With coolant temperature above 118 degrees F, connect a suitable tachometer to engine and a jumper wire between electro valve and ground. This will by-pass the thermo switch.
5. With engine idling, the EGR tester light A should be OFF.
6. Using the link rod, increase engine speed to 1200-1400 RPM on automatic transmissions and 1400-1600 RPM on manual transmission. The EGR tester light A should come ON.
7. Increase engine speed slowly, until engine speed reaches 3100 RPM. EGR tester light A should go OFF. If system test is correct proceed to "Vacuum Circuit Test." If not, proceed to "EGR Cycle Test."