EGR System: Non-Turbo
- Check all connectors, hoses and routings for cracks, leakage, or restrictions and repair as needed. Bring engine to normal operating temperature and run at idle. Remove and plug vacuum hose at EGR control valve. If engine runs rough, test EGR control valve.
- Remove plug from vacuum hose at EGR control valve and connect vacuum gauge. Remove and plug vacuum hose at bottom of EGR modulator valve and connect a suitable hose in its place. See Fig 1
. Increase engine speed to 2000 RPM and blow into hose. If no increase of vacuum is noted, test EGR modulator valve. Reinstall hoses to EGR modulator valve and EGR control valve.
Courtesy of MAZDA MOTORS CORP.
- Remove vacuum hose from EGR modulator valve marked No. 1 and connect vacuum gauge. Increase engine speed to 2500 RPM. Vacuum should be more than 5.9 in. Hg. Test 3-way solenoid valve if vacuum is less. With vacuum gauge still installed, disconnect Green/Black wire of water temperature switch. Increase engine speed to 2500 RPM and ensure no vacuum is present. If vacuum is present, test 3-way solenoid valve and EGI control unit at "2N" terminal.