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System Testing: Fuel-Injected

  1. Start the engine and warm it up until the cooling fan comes on. Open the control box lid and disconnect No. 16 vacuum hose from the top of EGR valve, connect a vacuum pump to the hose. Pinch the lower hose of the EGR control solenoid valve in the control box, and measure vacuum at idle. If vacuum stabilizes at 6-10 in.Hg (150-250 mmHg) within one second, the CVC valve and EGR hose routing is OK. If vacuum is not 6-10 in.Hg (150-250 mmHg) within one second, check the hose between the intake manifold and CVC valve for clogging or leakage. If the hose is OK, replace the CVC valve.
  2. Unclamp the lower hose pinched in step 1; again measure the amount of vacuum on the vacuum gauge. If vacuum is below 1.2 in.Hg (30 mmHg), the EGR control solenoid valve and hoses are OK. If the amount of vacuum exceeds 1.2 in.Hg (30 mmHg), check the air flow hose to the EGR control solenoid valve, and the No. 17 vacuum hose for blockage. If the hoses are not collapsed or blocked, replace the EGR control solenoid valve and recheck.
  3. Stop the engine. Reconnect the No. 16 vacuum hose, then disconnect the No. 21 vacuum hose from the throttle body. Plug the vacuum tap at the throttle body, connect a vacuum pump to the No. 21 vacuum hose, and apply a vacuum of 12 in.Hg (300 mmHg).
  4. Raise engine speed to 2000-2500 rpm. Feel operation of the EGR control solenoid valve with your fingers. If the EGR control solenoid valve is operating, the system is OK. If the EGR control solenoid valve is not operating, check the EGR control solenoid valve. See EGR CONTROL SOLENOID VALVE  . If the solenoid valve is OK, check Black/Yellow wire between the solenoid valve and Regulator fuse (10A), and Yellow wire between the solenoid valve and ECU. If wires are OK, check ECU. If EGR control solenoid valve is normal, check the EGR valve and lift sensor. See EGR VALVE  & EGR VALVE LIFT SENSOR  .
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