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EGR Function Testing - Volkswagen Volkswagen Fox G1

Emission Applications ~1206 words

1972-74 All Models

  1. Ensure ambient temperature is greater than 65°F (18°C). Run engine at idle speed and alternately move throttle valve from idle to partial load positions. When doing this, an audible sound should be heard from the electromagnetic cut-off valve.
  2. Disconnect vacuum hose from EGR valve and plug hose. Apply vacuum to EGR valve. Engine should run rough or stall. If EGR valve functions as described, system is functioning properly.

1975-79 Dasher

  1. Warm engine to normal operating temperature. Disconnect vacuum hose from distributor retard diaphragm and temporarily connect this hose to EGR valve.
  2. Engine should run rough or stall if EGR valve is working properly. If engine does not run rough or stall, check for clogged EGR ports or for faulty EGR valve.
  3. To check vacuum booster, connect vacuum gauge between vacuum booster and throttle valve port. With engine at idle, vacuum reading should be 2-4 in. Hg. If vacuum reading is not specified, check throttle valve port for blockage.
  4. With specified vacuum obtained, connect vacuum gauge between vacuum booster and temperature control valve. Vacuum gauge reading should be 2-4 in. Hg. If vacuum reading is not as specified, replace vacuum booster.

1975-77 Rabbit & Scirocco

  1. Check vacuum hoses for damage and proper routing. Start and warm engine to normal operating temperature. To test first stage of EGR valve, temporarily connect vacuum hose from anti-backfire valve to EGR valve. Engine should run rough or stall. If not, check for clogged EGR passage or faulty EGR valve.
  2. On California models, test full load enrichment switch. To test full load enrichment switch, turn ignition off. Connect ohmmeter to switch terminals. Close throttle valve. Ohmmeter should read infinity.
  3. Depress accelerator to floor. Just before pedal reaches floored position, ohmmeter reading should change to zero ohms. If not, adjust switch by loosening retaining screws. Repeat step 2 to verify proper adjustment.

1976-77 Type 1 & 2

  1. Turn ignition switch on and move throttle valve. The EGR valve should click. If EGR valve does not click, go to next step. If EGR valve clicks, go to step 3 .
  2. Unplug EGR valve connector and connect test light to it. With ignition switch on, move throttle valve. If test light illuminates at idle and at full throttle positions, replace EGR valve. If test light did not illuminate, check wiring or throttle valve switch.
  3. Start and warm engine to normal operating temperature. Remove plug from EGR valve. Engine should run rough or stall. If engine does not respond as indicated, go to next step.
  4. Check for vacuum signal at EGR valve. If vacuum is present, go to next step. If vacuum is not present, check vacuum line for damage or blockage. If line is okay on Type 2 models, replace thermal switch.
  5. Remove EGR valve and check for exhaust gas recirculation flow at idle. If no exhaust gas is present, check for plugged pipe or replace EGR filter. If exhaust gas flow is present, check outlet pipe for damage. Repair or replace as necessary. Replace EGR valve if system still does not work properly.

1978 Rabbit & Scirocco

  1. Start and warm engine to normal operating temperature. Disconnect vacuum hose to EGR valve and temporarily connect vacuum hose from power brake booster to EGR valve. Engine should run rough or stall. If engine does not respond as indicated, check for plugged EGR passage or faulty EGR valve.
  2. Connect vacuum gauge to temperature valve, in place of vacuum hose that goes to EGR valve. With engine at normal operating temperature, there should be 2-4 in Hg. If vacuum reading is not as specified, replace temperature valve.

1979 Rabbit & Scirocco

  1. Start and warm engine to normal operating temperature. Remove vacuum hose from distributor retard diaphragm and connect to EGR valve. Engine should run rough or stall. If not, check for clogged EGR passage or faulty EGR valve.
  2. Install vacuum gauge between EGR temperature control valve and EGR valve. With engine idling and at normal operating temperature, vacuum gauge should read 2-4 in. Hg. If vacuum reading is not 2-4 in. Hg, replace EGR temperature control valve.
  3. Install vacuum gauge between vacuum amplifier and temperature control valve. Vacuum gauge should read 2-4 in. Hg. If vacuum reading is not 2-4 in. Hg, replace vacuum amplifier.

1978-79 Type 1 & 2

Warm engine to normal operating temperature. Adjust engine idle speed, if necessary. Loosen both lock nuts on EGR adjusting rod. Shorten length of adjusting rod until EGR valve opens (engine runs rough or stalls). Now turn adjusting rod in opposite direction the specified number of turns. See EGR CONTROL ROD ADJUSTMENT table.

ApplicationTurns
Type 11 1/2
Type 2
A/T5/6
M/T1 1/6

EGR CONTROL ROD ADJUSTMENT

1980-84 All Models Except Diesel

Warm engine to normal operating temperature. Disconnect vacuum hose to EGR valve. Test EGR valve by temporarily connecting vacuum hose from distributor retard diaphragm to EGR valve. Engine should run rough or stall. If not, check for clogged EGR passage or faulty EGR valve.

1988-94 All Models Except Diesel

  1. Operate engine at idle speed. Using a hand-held vacuum pump, apply 12 in. Hg to EGR valve. Engine should run rough or stall. If engine does not run rough or stall, check EGR valve pintle for movement. If EGR pintle is moving, EGR port is plugged. If EGR valve does not function, replace EGR valve.
  2. To check EGR port vacuum supply, connect vacuum gauge to EGR vacuum line using a "T" fitting. Start engine and increase engine speed to about 3000 RPM. Vacuum gauge should indicate vacuum. If vacuum is not present, vacuum source is plugged. Repair as necessary and repeat test.

Cabrio, Golf III & Jetta III 2.0L

  1. Connect Scan Tool (VAG 1551) to Data Link Connectors (DLC) located below A/C-heater control panel. With scan tool in READ MEASURING VALUE BLOCK function, select group "02".
  2. Ensure there are no leaks in vacuum hoses and connections. Ensure vacuum hoses are not plugged or kinked and engine oil temperature is at least 122°F (50°C). Start and allow engine to idle.
  3. Connect hand-held vacuum pump to EGR frequency solenoid, and apply vacuum. Idle quality should change noticeably. If idle quality does not change, check vacuum hoses for obstructions, and EGR valve and manifold for plugging.
  4. If idle quality changes, read EGR temperature in display field No. 4 of scan tool. Temperature must rise steadily without interruption. If display is 127.4°C or less, there is an open circuit.
  5. If temperature rises steadily, disconnect vacuum pump as soon as value reaches 200°C. Press right arrow button on scan tool. Press "0" and "6" buttons to select END DATA TRANSFER function. Press "Q" button to enter input.
  6. If temperature value does not change, check EGR temperature sensor wiring harness for open circuit. If wiring harness is okay, replace EGR temperature sensor.

GTI, Jetta III 2.8L & Passat

  1. Ensure engine coolant temperature is at least 122°F (50°C). Start and allow engine to idle. Disconnect vacuum hose from EGR valve. Connect a hand-held vacuum pump to EGR valve and apply vacuum.
  2. Idle quality should change noticeably. If idle quality does not change, check EGR valve and exhaust manifold for plugging. Replace EGR valve if necessary. After repairs, clear/erase DTC memory.

TEST 11

For EGR function testing, see appropriate article in ENGINE PERFORMANCE section of electronic information product.

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