Signal Inspection
- Warm engine to operating temperature and allow to idle. Connect dwell meter to White check connector pin No. 1. Disconnect vacuum hose from vacuum sensor and plug hose.
- Connect vacuum pump to vacuum sensor. See Fig 1
. Apply 19.7 in. Hg. Verify dwell meter registers in 20-70 degree range. Release vacuum. Verify dwell meter indicates a fixed zero degrees. If dwell meter reading is not as specified, check vacuum sensor and terminal 1E voltage at ECU. See PIN VOLTAGE CHART
S article in the ENGINE PERFORMANCE section.
Courtesy of MAZDA MOTORS CORP.
- Remove vacuum pump and reconnect vacuum hose. Increase engine speed to 4500 RPM. Verify dwell meter indicates a fixed zero degrees. If reading is 72 degrees, check idle and neutral switches. If reading is other than zero or 72 degrees and other devices test within specification, replace ECU.