[oldbeaver]

Originally Posted by AndrzejM

Your pump is controlled by two factors:
1. gas pedal linkage - it's setting up rack position - thus main fuel dosage
2. ELR signal - it's changing by some percentage fuel dose to meet value counted by ECU, based on all the sensors

So you have to know rack position adt its offset by ELR signal, then you have the exact fuel dose. Combining that with rpm signal you have the exact moments when you have to measure rack position and offset. Lets call that a trigger signal. And finally combining that with VSS signal will give you FE.

And the other question about Y31 - I presume that's a valve for EGR

Ok, very good. Lets try to get the signals.

Rack position: there is a plug on the back of the governor of the injection pump with three wires. One of these should have the signal we want.

I took a picture of it but forgot how to insert here.

ELR signal: I am searching for it but won´t be difficult.

RPM signal is available in test socket. In this same socket there is an "diesel injection" signal, which I don´t know what is measuring, maybe just that the EDS is working ok.

You said to use RPM as the trigger signal as for when measuring the others, isn´t it?

Wouldn't it be possible to do the following, as an alternative:

Measure the rack position modulated by the ELR signal (surely some of the three wires has it already), and multiply it by the rpm value, for having a measure of how much fuel is being injected?

It would be a analog signal, I think.

I think it as follows: rack position tells how wide open is the gate that governs the passing of fuel (liters/stroke), while RPM tells at how much strokes per second it working the injection pump (strokes/sec).

Multipliying the first times the second should give liters/sec of injection.

Of course there are some constants to calibrate, as the pump may rotate at twice the speed of the engine, and we don´t know how much fuel per stroke each injector injects. But I think I have that info somewhere.

However, the liters/stroke each injector injects in the cylinder is not even at every rpm. It has a range that depends, again, on the RPM.

So, lets try to model that :

Iq = ((a + b*Rack * rpm)) + c*rpm*rpm

where:

Iq = inyected quantity (lts/sec)
a = callibration constant to be corrected with the full tank mileage
b = max injected volumen per stroke specific for the BOSCH pump
c = small value, probable negative, that indicates a limit vs RPM
Rack = rack position already modulated

How do you like it?

My intuition tells me it maybe less accurate, but simpler in the sense I think I can do it. While I don´t see how to materialize yr method. Maybe if you explain a Little more?


Best,

OldBeaver


VSS signal: I will see in which place I will get it.