The purpose of this test is to assess the intake air and valve system for cylinder-specific defects using the First-Look sensor.
Uninsulated HT pickups are designed to clip around double-insulated HT leads only – they are not designed for direct connection to a hazardous live voltage.
To prevent injury or death, when connecting or disconnecting an HT pickup:
Disable the vehicle fuel system before testing.
Some Engine Control Modules (ECM’s) will operate the throttle independent to pedal operation whilst attempting to start. This will alter your waveform. If this is the case you will need to disconnect the throttle body connector and re-test.
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.
Waveforms will vary from vehicle to vehicle, but should be consistent from cylinder to cylinder. Any variation suggests that one cylinder is drawing in a different amount of air/fuel mixture than the others.
This help topic is subject to changes without notification. The information within is carefully checked and considered to be correct. This information is an example of our investigations and findings and is not a definitive procedure. Pico Technology accepts no responsibility for inaccuracies. Each vehicle may be different and require unique test settings.
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November 20 2018
Hi Anthony, thank you for your observation. Test amended.
May 01 2017
Disconnect electronic throttle body, newer vehicles will play with the throttle during cranking to try and start the vehicle. This will mess up a pattern as the throttle is opening and closing during test drastically changing manifold vacuum.