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EGR Function Testing - Ford - Cars Ford LTD Crown Victoria I

Emission Applications ~1176 words

Ported EGR Valve

  1. Check vacuum hoses for correct routing. Connect a vacuum gauge directly to EGR vacuum source. With engine running, open and close throttle quickly to at least 1/2 open position. If gauge reading indicates vacuum, EGR vacuum supply is okay and vacuum port is open.
  2. If gauge reading indicates no vacuum, EGR vacuum port is plugged or restricted and should be cleaned. Disconnect vacuum hose at EGR valve, and plug hose. Connect a hand-held vacuum pump to EGR valve.
  3. Start engine. Apply 6-10 in. Hg to EGR valve. Engine speed should drop at least 100 RPM or stall. Vacuum should not drop greater than one in. Hg in 30 seconds. Reconnect EGR vacuum hose.

Backpressure Transducer EGR System

  1. Check vacuum hoses for correct routing. Connect a vacuum gauge directly to EGR vacuum source on carburetor. With engine running, open and close throttle quickly to at least 1/2 open position. If gauge reading vacuum is present, EGR vacuum port is open.
  2. If gauge reading indicates no vacuum is present, EGR vacuum port is plugged or restricted and should be cleaned. Disconnect EGR supply hose from EGR valve. Connect a hand-held vacuum pump to EGR valve. With engine at normal operating temperature, slowly apply 8 in. Hg to EGR valve. EGR valve stem should move to full extent of its travel and engine idle should roughen, RPM should drop or engine stall.

Integral Backpressure Transducer EGR System

  1. Inspect EGR vacuum hose routing for proper connection. Visually inspect EGR valve for obvious external defects, such as broken diaphragm vacuum nipple and blown-out gaskets. Disconnect and plug EGR vacuum supply hose. Connect a vacuum pump to EGR valve. Start engine. With engine at idle, apply 6 in. Hg to EGR valve.
  2. If vacuum holds and valve opens, EGR valve is defective. With engine at normal operating temperature, vacuum should be available to EGR valve at 4000 RPM on 1.6L engines, 3000 RPM for 2.3L engines or at 2000 RPM on all other engines. If vacuum is not available at specified RPM, check vacuum source. CAUTION: DO NOT block tailpipe fully. DO NOT operate engine faster than idle for prolonged periods. Be sure to remove plug from tailpipe at end of test. If these precautions are not followed, engine and/or exhaust system may be damaged.
  3. Clamp a plug (freeze plug may be used) into end of tailpipe; plug should be about 1/16" less than inside diameter. Connect a hand-held vacuum pump to EGR valve. Idle engine and apply vacuum gradually. EGR valve stem/diaphragm should move smoothly and engine speed should drop at least 100 RPM. Vacuum should not drop greater than 1 in. Hg in 30 seconds. If EGR system operates as indicated, system is functioning correctly.

Electronic EGR Valve

  1. Connect vacuum gauge to valve. Start engine. Apply 6-10 in. Hg to EGR valve and hold. Engine speed should drop at least 100 RPM or stall. Vacuum should not drop greater than 1 in. Hg in 30 seconds.
  2. Check vacuum lines for correct routing. Disconnect vacuum hose at EGR valve and connect vacuum gauge to hose. On 1.9L EFI, disconnect idle air by-pass valve. On all models, accelerate engine to 2000-2500 RPM and release throttle. Repeat 8-10 times and check for consistent response. NOTE: EGR Vent Solenoid (EGR-VSOL) allows a small amount of vacuum signal (less than 2.5 in. Hg) at idle.
  3. If vacuum reading is greater than zero with cold engine, EGR solenoid is leaking and should be replaced. With engine at normal operating temperature, vacuum should be greater than 15 in. Hg and return to zero when throttle is released. If EGR system operates as indicated, system is functioning correctly.

1994-96 All Except 2.5L (VIN B)

  1. Ensure all vacuum hoses are correctly routed and securely attached. Replace any crimped or broken hoses. Ensure less than one in. Hg vacuum to EGR valve exists at idle with engine at normal operating temperature. NOTE: EVR solenoid has a continuous internal leak which produces a vacuum signal of less than one in. Hg at idle.
  2. Install tachometer. Disconnect idle air by-pass valve electrical connector (if equipped). Remove and plug vacuum hose at EGR valve. Ensure transmission is in Neutral. Start and operate engine at idle. Note idle speed. Using vacuum pump, apply 5-10 in. Hg to EGR valve. When vacuum is fully applied to EGR, one or more of following should occur: Engine should stall. Idle speed should drop greater than 100 RPM. Idle speed should return to normal when vacuum is released.
  3. Repair or replace EGR valve if engine does not respond as specified. Reconnect idle air by-pass valve electrical connector. Unplug and reconnect vacuum hose at EGR valve.

EEC-V Equipped Vehicles

  1. Turn ignition off. Disconnect and plug vacuum hose at EGR valve. Connect hand vacuum pump to EGR valve. Connect scan tool to DLC.
  2. Start engine and bring to operating temperature. Allow engine to idle. Adjust scan tool to read EGR Differential Pressure Feedback Sensor voltage.
  3. Slowly apply 5-6 in. Hg to EGR valve and hold for 10 seconds. Keep engine speed at 800 RPM.
  4. As vacuum increases, voltage should rise to about 2.5 volts. When vacuum is held steady, voltage should hold steady.
  5. If EGR does not hold vacuum, check for defective EGR valve. If Differential Sensor Pressure Feedback Sensor voltage is not as specified, check for defective sensor. Also check for blocked EGR passages.

1.8L & 2.5L (EEC Systems)

  1. Turn ignition off. Disconnect and plug vacuum line to EGR valve. Attach hand vacuum pump to EGR valve. Start engine. Warm to normal operating temperature.
  2. Allow engine to idle. Slowly apply vacuum to EGR valve. Engine should stumble or stall. If not, check for defective EGR valve, or blocked EGR passages.

EGR Valve

  1. Ensure all vacuum hoses are correctly routed and securely attached. Replace any crimped or broken hoses. Ensure there is less than one in. Hg vacuum to EGR valve at idle with engine at normal operating temperature.
  2. Install tachometer. Disconnect Idle Air Control (IAC) wiring harness connector. Remove and plug vacuum hose at EGR valve. Start engine. Idle in Neutral. Note idle speed. Using hand vacuum pump, slowly apply 5-10 in. Hg vacuum to EGR valve. When vacuum is fully applied, engine should do one or more of the following: Engine should stall. Idle speed should drop more than 100 RPM. Idle speed should return to normal when vacuum is released.
  3. Service or replace EGR valve if engine does not stall or idle speed does not respond as specified. Reconnect IAC harness connector. Unplug and reconnect vacuum hose at EGR valve.

EGR Vacuum Regulator (EVR) Solenoid

Turn ignition off. Disconnect EVR solenoid wiring harness connector. Measure resistance across EVR solenoid terminals. If resistance is not 26-40 ohms, replace EVR solenoid. For additional testing, go to CIRCUIT TEST HE in appropriate article.

TEST 9

For EGR testing, see appropriate SELF-DIAGNOSTICS or SYSTEM & COMPONENT TESTING article in MITCHELL® ENGINE PERFORMANCE SERVICE & REPAIR DOMESTIC CARS, TRUCKS & VANS manual , or in ENGINE PERFORMANCE section of electronic information product.

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