DIS primary ignition voltage and current (using the 10:1 attenuator)

The purpose of this test is to examine primary ignition voltage and current within a DIS unit.

Connection guidance

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:

1. Breakout leads.
2. Back-pinning probes.

Testing sensors and actuators (to include relevant circuit/connectors):

• When testing a sensor, it is desirable to gain access at the control module.
• When testing an actuator, it is desirable to gain access at the actuator.

 

Note: This helpfile refers to a 10:1 attenuator. If you are using a 20:1 attenuator please adjust the Probe settings for the relevant channel. These settings can be found under the Channel Options button, then: Probe > 20:1 Attenuator.

How to perform the test

WARNING; 

This test involves measuring a potentially hazardous voltage.

Please ensure you follow manufacturers safety instructions and working practices and ensure the rated voltage for all accessories you are using meets or exceeds the expected voltage.

1. Ensure the ignition is turned off.
2. Connect the 10:1 attenuator into PicoScope channel A.
3. Connect PicoScope channel A to the ignition coil negative terminal and to earth.
4. Connect the low amp current clamp to PicoScope channel B. Select the 20 A scale and zero the clamp before clamping onto the coil power supply circuit.
5. Start the engine and run at idle.
6. Minimise the help page and with the example waveform on your screen PicoScope has already selected suitable scales for you to capture a waveform.
7. Start the scope to see live data.
8. With your live waveforms on screen stop the scope.
9. Turn off the engine.

10. Use the Waveform Buffer, Zoom and Measuring tools to examine your waveform.

Note;

If your current waveform does not appear or looks to be inverted. Stop the test, remove the clamp turn it around and re-fit. Then start and run the test again.

Example waveform

Waveform Library

Go to the drop-down menu bar at the lower left corner of the Waveform Library window and select, DIS / wasted spark ignition primary current, or voltage

Further guidance

For further information, see the following topics:

• Primary ignition voltage
• Primary ignition current

GT393-1

Suitable accessories