The fuel pressure in a common rail diesel system is more or less constant. The pump itself is merely that, unlike the earlier systems where the pump itself controlled the timing of the injection as well. The timing and duration of the injection is controlled by the injector, which in turn is fired by electric current under computer control.
We must be misunderstanding each other. (But just to be pernickety, even the pressure in the Hi-Press pump is varied slightly, via the "overspill"valve, by the ECU, according to demand - nothing that is relevant to my problem, however).
I agree entirely with what you have written above. The duration of your pulse is how long the little slide valve in the injector is open, and in practice, it opens and shuts several times per 720 degrees in a four stroke. This (as you know) is to do with burning carbon particles etc. All I was saying was that the pressure opens the pintle, but the solenoid "goes up and down" like a hatch and its piston valve isn't affected by pressure.
But anyway, I have to find a way to control the solenoid in the injector if I am to succeed in making my diesel work. I find those few who know are "too busy" or else the technical guys "just put things together" and only have a very rough idea of details.
A company called Hartridge, Milton Keynes, make a "black box" which will open and shut the injector, so it can be examined on the bench. The flow pattern, timing etc can be checked. I'm hoping they will give me useful info - they won't help materially. Won't modify a box to fire off the crank, for instance.
I plug on....
Malc
