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Hi, could someone please walk me through how to use the dead time table from injector dynamics to choose the appropriate deadtime values?: http://injectordynamics.com/injectors/id1000/

I have a base fuel pressure of 4 kg/56,89 psi, (measured with vacuum hose disconnected from fuel pressure regulator)

The injectors I have is a set of ID1000.

What confuses me is the psi(d) unit in the table, what does psi(d) even means?

If I where to have lets say 60 psi in base fuel pressure, would it be as simple as just copying the whole 60 psi row in the table into the ecu?

I tried this but when I do I can see that my AFR reading changed a lot when voltage goes up or down.

Simply I dont know how to use this table and can't seem to find any instructions on how to use it.

psi(a) = absolute (over total vaccum)

psi(g) = gauge (over atmospheric pressure)

psi(d) = differential (over a vacuum or pressure reference)

If you disconnect the vacuum hose, then your reference is the atmospheric pressure, so psi(d) = psi(g)

As for the value, yes you just have to copy/paste the row corresponding to your pressure.

(just be careful with the scale, ID give the offset in µsec not in msec)

As Ludo mentioned, the units psi d refers to differential pressure. This is the difference between fuel pressure and manifold pressure.

The reason this is important is that both the flow of the injector and the deadtime values will fluctuate as the differential pressure varies - Let me explain a little more thoroughly:

Most people can get their head around the fact that as fuel pressure goes up, the injector flow increases. A subtle aspect of this is as the fuel pressure goes up, the deadtime increases too as it's harder to open the injector against the higher pressure. What's a little less obvious is that it's not the fuel pressure specifically that's important but the differential pressure across the injector.

This means that if you leave the pressure fixed and decrease manifold pressure, this has the same effect as increasing the fuel pressure.

Ok with that out of the way a more specific answer to your question is that you need to choose the deadtime and flow data to suit the differential pressure you're running. If for example you're running 58 psi fuel pressure with the vacuum hose to your regulator disconnected, this is the differential pressure and you need to use the data from this part of your deadtime table.

Things get a little more complex in a returnless system as the deadtime and flow varies dependent on manifold pressure too and the proper way of accounting for this is with a 3D deadtime table relative to batt volts and differential fuel pressure.

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