Merkur Xr4ti L4-140 2.3L SOHC Turbo (1985)
Invalid Test
1.
Connect an engine analyzer equipped with an oscilloscope. Follow the manufacturer's instructions for hook-up and operation.
2.
Start the engine.
3.
Disconnect spark plug wire to any accessible cylinder and observe voltage applied to disconnected spark plug wire on oscilloscope. This voltage,
referred to as an open circuit output voltage, should be 24,000 volts (24 kV) minimum with engine speed at 1000 rpm.
CAUTION: Operate the engine with the spark plug disconnected only long enough to get an oscilloscope reading. Prolonged operation with the wire
disconnected can lead to catalytic converter overheating and possible damage.
OSCILLOSCOPE CHECKS
The oscilloscope provides a convenient means of observing secondary ignition circuit operation while the engine is running. It displays a graphic
waveform trace pattern that reflects the actual voltages required to fire each spark plug. Through interpretation, the scope pattern can be used to diagnose
conditions affecting all cylinders or just one cylinder. When connecting an engine analyzer equipped with a scope, always follow the manufacturer's
instructions for hook-up and operation.
NOTE:
It is essential that the calibration of the engine analyzer be maintained for accurate results.
