Initial Inspection and Diagnostic Overview

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/obstructions in the exhaust pipe or a plugged three way catalytic converter/muffler.


TEST METHOD (VEHICLE PARKED):
1. Remove oxygen sensor.
2. Connect gage bar tool kit (SA9127E) (0-60 in H2O).
3. With engine at normal operating temperature, observe exhaust back pressure at constant 4000 rpm for 5 seconds.
4. Back pressure must be less than 20.13 inch H2O (5.0 kPa).

NOTICE: IF EXHAUST PRESSURE EXCEEDS SPECIFICATION, INSPECT FOR DENTS/OBSTRUCTIONS. IT MAY BE NECESSARY TO DISCONNECT THE MUFFLER OR THE PIPE BEFORE OR BEHIND THE CONVERTER AND REPEAT THE TEST.

5. Replace damaged or defective parts.
6. Remove test equipment.

NOTICE: USE NON SILICON ANTI-SEIZE COMPOUND ON THE THREADS. IT MAY BE NECESSARY TO USE A SCAN TOOL TO DELETE ANY CODES SET WHILE PERFORMING PRESSURE TESTS.

7. Install oxygen sensor and tighten.
Torque:
Oxygen Sensor: 45 Nm (33 ft. lbs.)