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EGR Function Testing Ford Aerostar I

Testing & Diagnostics ~222 words

PORTED EGR VALVE

  1. Check vacuum hoses for correct routing. Connect a vacuum gauge directly to EGR vacuum source. With engine running, open throttle. If gauge indicates vacuum, EGR vacuum supply is okay.
  2. If gauge indicates no vacuum, EGR vacuum port is plugged. Disconnect vacuum hose at EGR valve, and plug hose. Connect a vacuum pump to EGR valve.
  3. Start engine. Apply 6-10 in. Hg to EGR valve. Engine should run rough or stall and EGR valve should hold vacuum. If engine speed does not change, check for plugged EGR passages or faulty EGR valve.

ELECTRONIC EGR VALVE

  1. Connect vacuum gauge to EGR valve. Start engine. Ensure there is less than 1 in Hg to EGR valve at idle with engine at normal operating temperature. NOTE: EGR Vent Solenoid (EVRV) allows a small vacuum signal (less than 2.5 in. Hg) at idle.
  2. Install tachometer. Disconnect Idle Air By-Pass Valve (IABV) harness connector (if equipped). Disconnect and plug vacuum hose to EGR valve. Start engine and idle in Neutral. Note idle speed. Using a hand-held vacuum pump, slowly apply 5-10 in. Hg to EGR valve.
  3. Engine should either stall or idle should drop at least 100 RPM. Idle speed should return to normal when vacuum is released at EGR valve. Repair or replace EGR valve if none of the conditions occur.