Hi all

The attached PSD file is from a 2003 Nissan Primera P12 with a QR25 direct injection engine.

The trace is from a known good system, appart from the brake sensor being open circuit [one on order]

My question is about understanding the waveform and what it means.

This injector is a three wire type and I wondered if anyone could explain the process of the different traces. It look as though the ChA trace is very close to a normal one and the current ChC is the same, however, what is ChB telling me?

I appoligise now if this question is regarded simple but I am just trying to expand my grey cells.

Regrds

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s4cs4c wrote on Sep 25^th, 2011 at 5:51pm:

It look as though the ChA trace is very close to a normal one and the current ChC is the same, however, what is ChB telling me?

the pcm is controlling both sides of the injector.  cha opens it quickly while chb is holding it open.  i'm guessing, depending on rpm and such, that you might see one or both waves being pulse width modulated.  

Looks like a peak - hold injector. It looks as if current reverses through chanB when chanA is on, with the chanB circuit being responsible for holding the injector open.
Im not 100 percent sure - im just going by what i see here. its definitely something I havent seen before. thanks for sharing this.

I could be wrong about this and probably am - I have some other ideas about how it works - but i figured id be the first to stick my neck out and risk looking like an idiot ;D

One of my other ideas is that the may be two separate solenoids inside the injector - I might be able to say more if we had more traces from all three wires.

Hi Randy
I do find that 'sticking you head out' does tend to get you shot, however, when the blood dries there tends to be alot more clarity.

Just to add to this, current is taken from the 10amp fuse supplying voltage to the injector. Both of the other traces are ECU controled.