Exhaust Gas Recirculation: Testing and Inspection

Fig. 28 EGR vacuum modulator & BVSV test.:

2S-E & 3S-FE ENGINES

1. Inspect EGR vacuum modulator filter and clean or replace as needed.
2. Connect vacuum gauge in line with EGR valve vacuum hose using a suitable fitting.
3. Start engine and ensure engine idles properly. If engine runs rough or stalls, check for improperly seated EGR valve.
4. With coolant temperature below 113°F, run engine at 2500 RPM and observe vacuum gauge. If gauge reading is not zero, BVSV is defective.
5. Warm engine to normal operating temperature and observe gauge reading at 2500 RPM. Gauge should indicate low vacuum.
6. Disconnect vacuum hose from port ``R'' of vacuum modulator and apply manifold vacuum to port ``R'', Fig. 28. Gauge should indicate high vacuum at 2500 RPM.
7. If readings in steps 5 and 6 are not as specified, check for defective vacuum modulator.
8. Remove vacuum gauge and connect hoses to proper ports on modulator and EGR valve.