Fuel Injected
- With engine cold, start engine. Verify presence of vacuum to ignition control solenoid. If vacuum is not present, turn ignition off and check hose for cracks, blockage or disconnection. Also check vacuum port at throttle body for blockage.
- If vacuum is present, increase engine speed to about 1500 RPM. Check for vacuum at advance diaphragm "B" (outer) of distributor. If vacuum is not present, check for blocked or disconnected hose between solenoid and diaphragm "B". If hose is okay, go to step 4). If vacuum is present, allow engine to idle until cooling fan comes on. Increase engine speed to about 1500 RPM and check for vacuum at distributor diaphragm "B".
- If vacuum is not present, system is functioning properly. If vacuum is present, check for short to ground in White wire between connector and ECU. If wire is not shorted to ground, substitute a known good ECU and retest. If symptom is rectified, replace original ECU.
- Disconnect 6-wire connector at control box. Check voltage between ground and Black/Yellow wire of connector harness. If battery voltage is present, go to next step. If battery voltage is not present, turn ignition off. Check Yellow/Black wire for open or short between solenoid connector and ignition fuse No. 4 or replace fuse.
- Check voltage between Black/Yellow (pos.) and White (neg.) wire terminals of harness connector with engine speed about 1500 RPM. If engine is cold, battery voltage should be present. If engine is at operating temperature, no voltage should be present.
- If voltage readings respond as indicated, and vacuum is still not present at distributor vacuum diaphragm "B", replace solenoid. If voltage readings do not respond as indicated, substitute a known good ECU and retest. If symptom is rectified, replace original ECU.