The latest instalment in our series of real-life diagnostic stories concerns a misfiring 2001 Vauxhall Astra 1.6. Professional motor mechanic Nick Hibberd finds only a “General Misfire” fault code, so he has to rely on his PicoScope diagnostic oscilloscope. Nick explains how to capture and interpret current and voltage patterns from the ignition system, and how to use them to track down a faulty component.
Here is a quick tip for those of you who have updated to PicoScope 6.
Following on from last month’s tip on the window buffer, we can now look at basic trigger functions.
I am sure you are used to using the stop and start buttons at the bottom left of the screen, but have you noticed the drop-down box displaying ‘None’? This is the trigger selection box. If you click this box and change ‘None’ to ‘Single’, a yellow diamond appears on the scope screen. This can be positioned by dragging it around the screen using the mouse or by using the value boxes at the bottom of the screen; the first being for channel selection, the second for the numerical value and the third for its position as a percentage of the screen width.
The scope waits until the trigger threshold is passed, then captures a trace and holds it on the screen, enabling you to capture something like an airflow meter without having to stop the trace yourself. You can also choose to trigger on the rising or falling edge of the trace, which is useful for something like an injector trace where triggering on the falling edge of the voltage trace when it is switched to ground allows the waveform to 'grow' across the screen as the fuelling duration changes. Switching to a repeat trigger causes a screen capture to be stored within the buffer for each trigger event, conveniently combining the use of a single trigger with the window buffer from last month!
Here’s a summary of the latest technical resources that you can find, free of charge, on our website.
If you are thinking of upgrading to our latest USB 4-channel scope, now is the time!
For a limited period, we are offering a 20% discount off the price of our 4-channel upgrade kit if you trade in your ADC-212 parallel port model. Please contact our sales department to place your order.
If you own, or are thinking of buying, a Pico Automotive Diagnostics Kit, you mustn’t miss our Engine Management Diagnostics course. This provides expert training on the fundamentals of engine management diagnostics, together with plenty of hands-on experience with our kit. The course is run several times a year around the UK.
These courses are popular, so book your course now!
Engine Management Diagnostics using PicoScope
Preston College, Preston, Lancashire
20-21 May 2008
This two-day course introduces the basic working principles of engine management systems, component testing and system diagnostics using oscilloscopes. The course is split between theory sessions and practical demonstrations in a workshop using the Pico Automotive Diagnostic Kit on engine rigs.
Visit the exhibitions page at picotech.com for full details of upcoming exhibitions and training dates.
Due to our continuing growth, we have vacancies for the following positions:
We look forward to hearing from you if you want to be part of a growing company at the leading edge of test equipment design.
Please visit Pico Exhibitions for the latest list of exhibitions and trade shows that Pico and its representatives will be attending.
Thanks to our continuing success and growth Pico are always seeking talented people to join our company.
Please visit http://pico.jobs/ to see our current vacancies. We look forward to hearing from you!
Our latest software releases are available as free downloads. To check which release you are using, start the software and select Help > About.
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Pico Technology, James House, Colmworth Business Park, St. Neots, Cambridgeshire, PE19 8YP, England
Tel.: 01480 396395 (+44 1480 396395)
Fax: 01480 396296 (+44 1480 396296)
Pico Technology North America Inc.
320 N Glenwood Blvd.
Tel:+1 800 591 2796 (Toll Free)
Fax:+1 620 272 0981
Web technical support: www.picotech.com/tech-support/