EGR System

Ensure modulator filter is clean and in good condition prior to performing test. Clean filter with compressed air if necessary. Disconnect vacuum hose from EGR valve.
Using a "T" connector, connect a vacuum gauge in EGR valve line. Check that engine starts and runs at idle. This ensures proper seating of EGR valve.
The BVSV, TVSV, VSV and EGR modulator can be checked with engine coolant at certain temperatures and engine RPM in accordance with application. See EGR SYSTEM SPECIFICATIONS table. Different valves are used depending on model.
Operate engine at minimum temperature and RPM. No vacuum reading should be obtained when operated at minimum temperature. Operate engine at normal operating temperature and specified RPM.
Low vacuum reading should be obtained. Vacuum reading of 2.6 in. Hg should be obtained on Cressida and Supra models. On Cressida and non-turbo Supra models, check that no vacuum is shown at idle. Corolla models with EFI and the MR2 models should be checked at 5000 RPM showing no vacuum.
Disconnect hose from the "R" port of EGR vacuum modulator on all models except the Tercel Wagon, Pickup, 4Runner with EFI and turbocharged Supra. See Fig 1 through Fig 13 ..
Using additional hose, connect "R" port directly to intake manifold. High vacuum reading should be obtained at specified RPM. See EGR SYSTEM SPECIFICATIONS table. Disconnect vacuum gauge and install vacuum hoses.
NOTE: Engine should misfire due to large amounts of exhaust gas being injected into intake manifold.
To check EGR valve, apply vacuum directly to EGR valve with engine idling. Engine should run rough. If system did not operate within specifications, each component should be tested. See COMPONENT TEST .