Renault Megane K9K injector voltage walking spike?

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Renault Megane K9K injector voltage walking spike?

Postby LEYLAND MILL MOTORS » Mon Sep 14, 2015 6:14 pm

We have had in today a Renault Megane II 1.5 dCi k9k

The vehicle had a fuel pressure regulator issue which was producing low fuel pump pressure. Delphi pump and false actuators confirmed the fault, regulator changed job done.

While waiting for parts I took the opportunity to get a few reference waveforms.

I was looking at the injector voltage and current on cylinder 1 and noticed a few extra spikes in the voltage trace.
Hooking up voltage to number 2 injector and reference from crank, I noticed a "walking 40 ish volt spike" going between main injection pulses.

Looking at Autodata online, the pizo injectors are connected directly to the ecu separately with no indication of supply or earthing.
I believe the ecu all injectors on each firing stroke with the ecu controlling the earth to operate the injector when required.

I have not noticed this in any others I have checked or tested, this dose not appear to be causing any problems? Yet??
The vehicle runs fine but I am not sure what would give a 40volt spike like this?
Any thoughts or suggestions.
Thanks
Steven
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Renault_Megane_2007_Diesel_20150914-0003 FILTERED WALKING SPIKES.gif
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Re: Renault Megane K9K injector voltage walking spike?

Postby Robski » Mon Sep 14, 2015 7:11 pm

probably charging the capacitor's.
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Re: Renault Megane K9K injector voltage walking spike?

Postby LEYLAND MILL MOTORS » Mon Sep 14, 2015 7:17 pm

Thanks for that
Makes total sense now
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