Common Rail 5

Anyone who does a lot of research on the Internet will also come across a lot of things that are incomprehensible, either because the writing is written by someone who is too clever or rather ignorant.
All that remains is the hope that we do it a little better in this book. Topic: the subsequent registration of injectors. We've already covered this, but it should be dealt with in more detail here as a separate topic. Above all, the
clear naming of the topic offers the possibility that only those who are really interested and directly affected will read on.
As already explained, injectors must be registered or, better still, made known to the engine control unit, because they obviously cannot be manufactured so precisely that they fit into the control range of the electronic
control unit. Perhaps you should imagine it like this: An engine is started with any injectors. That would then be the starting value for fine tuning that is carried out by the control unit. However, limit values must be adhered to
for this.
Without the motor running first, such feedback is not possible. In any case, you have to avoid excessive runaway values. During production, the tolerances are obviously so large that the control unit has to be given a range.
Incidentally, it cannot get out of this range. So if injectors are incorrectly classified, for example if they actually belong to the neighboring range, they will probably be changed up to the edge of this control range and that is all
that is possible.
This means that a message must be sent to the engine control unit whenever an injector has been replaced. It does not matter whether an old one has been replaced with a new one or vice versa. Repairing injectors
could be more complicated, as this requires the most precise measuring and adjustment work and possibly a new nozzle. It is difficult to answer how they achieve compliance with the printed classification. At least there
are test benches, so they can measure according to data sheets and probably also change the entry on the top of the injector.
It is not really conceivable otherwise. So the answer to the question of when injectors have to be re-registered should be quite clear. If you only remove them, clean them and reinstall them, you can save yourself the trouble.
Incidentally, it is actually hard to imagine that an injector can be 'cleaned'; if you can't even see the blind holes with the naked eye, the action seems pretty pointless, perhaps even detrimental. You can certainly clean their
seat and surroundings in the cylinder head and thus prevent major problems during future disassembly, but that's about it.
One more thing: If you approach the matter very meticulously, you can compare the six-digit codes of the new and old injectors and then perhaps find that they belong to the same group. But we won't deal with that here
because we want to tackle the matter in principle. So we code and at the same time check whether the retained injectors are entered correctly. Of course, the utmost care is required when reading and entering the six-part
code (picture above).
There must be no spelling mistakes, although we have also experienced codes being rejected, so probably only very specific ones are allowed. And when you then drive off, the engine may feel better for a short time, but
then usually significantly worse. The reason could be that the engine control unit has got used to some old values and of course has no other chance of transferring them to the new coding.
From our experience, we can only advise you to drive at varying speeds, although the same speed in fourth and fifth gear probably makes no difference to the control unit. There is also no set number of kilometers at which
the programming changes. Sometimes it suggested: 'We understand', but the next day it reverted back into its old position. Good advice on this: perhaps deliberately seek out, for example, critical areas, as long as the rest
of the traffic allows it. With only 130 km/h on the highway, the control unit cannot repair problems at 80 km/h.
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