GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Oldsmobile 🢒 1998 🢒 LSS 🢒 Engine 🢒 Engine Controls - 3.8L 🢒 Restricted Exhaust System Check

Restricted Exhaust System Check

Step

Action

Values

Yes

No

1

Did you perform the On-Board Diagnostic (OBD) System Check?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2
  1. Remove HO2S 1. Refer to Heated Oxygen Sensor Replacement .
  2. In place of HO2S 1, install J 35314-A Exhaust Back Pressure Tester.
  3. Start the engine.
  4. With the engine idling at normal operating temperature and the transaxle in Park, observe the exhaust system back pressure reading on the gauge.

Does the reading exceed the specified value?

8.6 kPa (1.25 psi)

Go to Step 4

Go to Step 3

3
  1. Leave the transaxle in Park.
  2. With the exhaust each pressure tester or equivalent in place of HO2S 1, increase engine speed to 2000 rpm.
  3. Observe the exhaust system back pressure reading on the gauge.

Does the reading exceed the specified value?

20.7 kPa (3 psi)

Go to Step 4

System OK

4
  1. Reinstall the HO2S 1.
  2. Remove HO2S 2. Refer to Heated Oxygen Sensor Replacement .
  3. In place of HO2S, install J 35314-A Exhaust Back Pressure Tester.
  4. Engine at normal operating temperature.
  5. Leave the transaxle in Park.
  6. Increase engine speed to 2000 rpm.
  7. Observe the exhaust system back pressure reading on the gauge.

Does the reading exceed the specified value?

20.7 kPa (3 psi)

Go to Step 5

Go to Step 6

5

Locate and repair the restriction in the exhaust system past the three way catalytic converter. Inspect the following parts for possible malfunctions:

    • Collapsed pipe
    • Heat distress
    • Internal muffler failure

Is the action complete?

--

Go to Step 7

--

6

Replace the Three Way Catalytic Converter. Refer to Muffler Replacement in Exhaust System.

Is the action complete?

--

Go to Step 7

--

7
  1. Remove HO2S 1. Refer to Heated Oxygen Sensor Replacement .
  2. In place of HO2S 1, install J 35314-A Exhaust Back Pressure Tester.
  3. Leave the transaxle in Park.
  4. Engine idling at normal operating temperature
  5. Observe the exhaust system back pressure reading on the gauge.

Does the reading exceed the specified value?

8.6 kPa (1.25 psi)

Go to Step 4

Go to Step 8

8
  1. Leave the transaxle in Park.
  2. With the exhaust back pressure tester in place of HO2S 1, increase engine speed to 2000 rpm
  3. Observe the exhaust system back pressure reading on the gage.

Does the reading exceed the specified value?

20.7 kPa (3 psi)

Go to Step 5

System OK