Sidekick 2WD L4-1590cc 1.6L SOHC 0 TBI 8V (1992)
Catalytic Converter: Testing and Inspection
Restricted Exhaust Check
RESTRICTED EXHAUST SYSTEM DIAGNOSIS
A partially restricted or blocked exhaust system usually results in a loss of power or backfire up through the throttle body. Verify that the condition is not
caused by ignition or fuel system problems, then perform a visual inspection of the exhaust system. If the condition cannot be located by visual
inspection, perform the following procedure.
- Attach a vacuum gauge to the intake manifold.
- Connect a tachometer to the ignition coil negative (TACH) terminal.
- Start the engine and observe the vacuum gauge. The gauge should indicate a vacuum of 16-21 inches Hg.
- Increase the engine speed to 2000 rpm and observe the vacuum gauge. The vacuum will decrease when the speed is increased rapidly, but should
stabilize at 16-21 inches Hg and remain constant. If the vacuum remains below 16 inches Hg, the exhaust system is restricted or blocked. Stop the
engine and proceed to the next step.
- Disconnect the exhaust pipe at the manifold.
- Start the engine and increase the speed to 2000 rpm. Observe the vacuum gauge.
- If the vacuum stabilizes at 16-21 inches Hg, restriction or blockage is either in the exhaust pipe, catalytic converter, muffler or tail pipe.
- If the vacuum stabilizes below 16 inches Hg with the exhaust pipe disconnected, the exhaust manifold is restricted.
- Stop the engine, connect the exhaust pipe and remove the muffler. Start the engine and increase the engine speed to 2000 rpm. Observe the vacuum
gauge.
-
If the vacuum stabilizes below 16 inches Hg, the restriction is in the catalytic converter.
NOTE: In the event of a catalytic converter failure, always inspect the muffler and ensure converter debris has not entered the muffler.
-
If the vacuum is normal, the muffler or tail pipe is restricted.
-
Stop the engine.
-
Disconnect the tachometer and vacuum gauge.
