Well Ive just received my 20:1 attenuator to use for analyzing the injector waveforms on my 1994 volvo  850.
Looking for advice on oscilloscope connection to avoid damaging the unit,any recommendations.
I'm not using a pico scope just a standard labscope.

cheers Ian

What amount of voltage will your Lab Scope handle un-attenuated?  I back-probe the control side of the connector, either at the Injector or the ECM, whichever is most accessible with access to a solid Ground (Earth), and start her up. If none of the smoke escapes my scope it's a brighter looking day. :D  Is yours PC Based, so captures can be saved and compared later? I'm sure we all would like to see what you have accomplished.  Or do you have to rely on memory for the comparison? I'd be lost on that one, I have to check the phonebook to be sure I spelled my name right. :'(  Good Luck.

If I chose the correct vehicle, it looks like they are all fired at the same time.  Makes it easy to pick which wire, the grey one.  This may be a good one to also practice using your current probe ( if you have one ).  Make sure you have your scope grounded, install your new shiny attenuator ( I would also double check to see if you need it like RT mentioned, but when in doubt use it anyway first and go from there ), and backprobe any of the injectors on the gray wire.  If you have an amp probe you can check the injector amps too, but this image may change depending on where you have it placed and the condition of the injectors and their circuits.  Try the voltage trace first and try to post up the image of what you got and we'll go from there.

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Thanks for the help.
The scope can accept 400vs and is a semi digital  unit that can be linked to a laptop for capturing  waveforms,so ill post some of the results
cheers

Ian

My first go at grabbing  injector waveforms on my 1994 volvo,didnt have time to hook to a computer so i took a screen shot.
All 5 injectors have the same waveform

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bangshout , was this a cold engine?  I really don't see anything wrong (If I'm reading the scale for timebase correctly) 9.2 ms on time cold isn't unbelieveable.  What are the Divisions for voltage?  Other than your Lab Scope having a higher sample rate than our PC based Automotive Units the inductive kick on ours generally appear pretty much vertical until we Zoom way in. To this Neophyte it looks like good injectors cold, we scope on a really long timebase to see if there is a problem that develops as the temperature rises, and zoom in on the anomalies that appear. I can't locate one of my files just now, to show what ours look like before and after zoom.