SW1 L4-1.9L SOHC VIN 8 (1996)
Catalytic Converter: Testing and Inspection
Restricted Exhaust System Check
Exhaust System Pressure Check
RESTRICTED EXHAUST SYSTEM CHECK
A slight pressure in the exhaust system is normal, but excessive exhaust back pressure seriously affects engine operation. Causes of high exhaust
back pressure are dents or obstructions in the exhaust pipe, a plugged three way catalytic converter or muffler.
Test method (Vehicle Parked):
1. Remove the oxygen sensor.
2. Insert exhaust back pressure adaptor (SA9306E) into the exhaust manifold. The thread designation is M18 x 1.50.
3. Connect the gage bar kit (Saturn Tool) SA9127E, 0-15 kPa gage (0-60 in. H2O) to the back pressure adaptor.
4. With the engine at normal operating temperature, observe the exhaust back pressure at 4000 rpm.
5. The exhaust back pressure must be less than 5.0 kPa (20.13 in. H2O).
Test method (Performed During Test):
1. Remove the oxygen sensor.
2. Install exhaust back pressure adapter (SA9306E) into the exhaust manifold. The thread designation is M18X1.50.
NOTE: Do not use the 0-60 in. 1120 gage when performing this test, as it will be permanently damaged due to the excessive back pressure
during accelerations. Use the 0-690 kPa (0-100 psi) gage and appropriate hoses in service gage bar kit (Saturn Tool) SA9127E.
3. Connect the gage bar kit SA9127E, 0-861 kPa (0-100 psi) gage.
4. With the engine at normal operating temperature, perform a 15 mph road test. Automatic transaxies should be in "D" and manual Transaxies in
"3rd" gear. Maximum exhaust back pressure readings are taken during short wide open throttle accelerations.
5. The maximum exhaust back pressure during wide open throttle accelerations must be less than 50 kPa (7.25 psi).
NOTE: If the exhaust pressure exceeds the specification, inspect for a dented or collapsed exhaust pipe. It may be necessary to disconnect the
exhaust pipe before or behind the converter and repeat Step 4. If removing the muffler does not lower the back pressure, disconnect the three
way catalytic converter from the front exhaust pipe and repeat the test.
6. Replace any part of the exhaust system found to be damaged.
7. Install anti-seize on the oxygen sensor's threads and install the sensor. It may be necessary to disconnect the negative battery terminal in order
to clear any codes set while operating the engine with the oxygen sensor removed or disconnected.
