Triggered Cranking Exhaust Test

How to connect the oscilloscope

Example waveform and notes

How to connect the oscilloscope

Connect the First Look Sensor to Channel A on the PicoScope using the 25ft BNC to BNC cable as shown in Figure 1.0, then attach the sensor to the exhaust pipe as shown in Figure 1.1.

Now connect the Secondary Ignition pick-up Lead to Channel B of the scope and attach the clamp to the cylinder 1 plug lead. Once you have disabled the fuel system (may not be possible on a carburated engine), crank the engine until the display pattern stabilizes. You can adjust the timebase and voltage scales to achieve best signal display.

This test is useful when it is desirable to obtain cylinder specific data without the engine running. You will need to disable the fuel system to perform this test. This test allows us to look at the action of the valve train and cylinders, exhaust valve action per cylinder and problems with the head or head gaskets may be assesed.

Example FirstLook sensor waveform

FirstLook sensor waveform notes

This waveform shows a consistent signal pattern on Channel A as triggered against Channel B on the same time line. Cursor lines are added to show trigger reference (sparkplug 1) and show the time between trigger events. We can use this information to determine the approximate cranking speed of this engine.