The purpose of this test is to assess the intake air and valve system for cylinder-specific defects on the intake side of the engine using the FirstLook sensor.
Connection for diagnostic work will vary dependent on application.
Technicians should whenever possible gain access to the test circuit without damage to seals and insulation. If this is not possible then make sure appropriate repairs are completed.
General connection advice
PicoScope offers a range of options within the test kits.
Dependent on difficulty of access, choose from:
Testing sensors and actuators (to include relevant circuit/connectors):
Warning: When attaching or removing secondary ignition pickups from damaged HT leads there is a danger of electric shock. To eliminate this possibility, switch off the ignition before attaching or removing the secondary igntion pickup.
Disable the vehicle fuel system before testing.
Some system 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.
Go to the drop-down menu bar at the lower left corner of the Waveform Library window and select, Intake manifold pressure waveform.
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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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.