EGR System - Low Altitude (4 Sp. Auto. Trans. - Wagon)

Fig. 013 EGR System - Low Altitude (4 Sp. Auto. Trans. - Wagon) (Same as Fig. 49, p. 13-20):

VIN T LOW ALTITUDE (NA5), "A" WAGON WITH 4 SPEED AUTO. TRANS.

Vacuum from the vacuum pump is modulated by the Vacuum Regulator Valve mounted on injection the pump. Vacuum is highest at idle and decreases to 10 kPa ± 3 (3.6 Hg. ± .9) at wide-open throttle. This variable vacuum then is sent to the Altitude (TRIM) Solenoid and the transaxle vacuum modulator Vacuum Reducer Valve and the Altitude Vacuum Reducer Valve.
The altitude Solenoid is energized by the EGR Altitude Sensing Control switch at altitudes above 1219 meters (4,000 ft.). When it is not energized, ports 2 and 3 (of the solenoid) are connected and port 1 is blocked. Therefore vacuum at port 2 of both Vacuum Reducer Valves (VRV) are the same. This causes the vacuum at port 1 of both VRV's to also be the same as the vacuum at ports 2 and 3. When the Altitude Solenoid is energized, ports 1 and 2 of the solenoid are connected and port 3 is blocked. Because port 1 of the Altitude Solenoid is a vent, port 2 of both VRV's are open to atmospheric pressure. Now both VRV's will regulate. The vacuum at port 1 of the Altitude VRV will be 8.44 kPa (2.5 Hg.) lower than the vacuum at port 3 of the altitude VRV. The vacuum at port 1 of the Transaxle VRV will be 5 kPa (1.5 Hg.) lower that the vacuum at port 3 of the transaxle VRV.
Port 1 of the Transaxle VRV is connected to port "S" of the Transaxle Quick Vacuum Response (QVR) valve. When the vacuum applied to any QVR at port "S" is constant or increasing, the vacuum output will be the same as the input. When the vacuum at port "S" drops, the vacuum on the output side is quickly vented through the vent port of the QVR, until it equals the vacuum at port "S".
Port 1 of the Altitude VRV is connected to port 3 of the Transaxle Converter Clutch (dump) solenoid. The TCC solenoid prevents vacuum from passing through whenever the Transaxle Converter Clutch is engaged. When the solenoid is energized, any vacuum present beyond the solenoid is vented through the "vent" port (1) of the solenoid. When the solenoid is not energized, vacuum is applied to port 3 of the EGR Thermostatic Vacuum Switch (EGR-TVS).
The EGR-TVS is installed in a coolant passage of the intake manifold. It does two things; 1. its upper part is an electrical switch that energizes the HPCA and fast idle solenoid when coolant temperature is below 35°C (95°F). 2. its lower part is a vacuum switch that prevents vacuum from flowing to port 2 until 41°C ± 2° (105°F ± 3.6°) coolant temperature is reached. Below 35°C (95°F) vacuum cannot pass from port 3 to 2. Any vacuum that was present at port 2 is vented through port 1. Port 1 is blocked when ports 3 and 2 are connected.
Vacuum is then sent to the EGR-QVR. The EGR-QVR operates the same as the Transaxle Modulator QVR. The EGR-QVR will quickly equalize the vacuum present in the EGR valve when vacuum input to port "S" of the QVR drops. The EGR valve is a vacuum modulated type. It should be fully open at 40.5 kPa (12 Hg.) and closed below 25.3 kPa (7.5 Hg.). VIN T