Injectors
It is one of the most common conversations we have in the workshop. A customer comes in with a note from another garage: all four injectors need replacing, and it comes to DKK 15,000 or more.
Sometimes that is right. Often it is not.
Not out of bad intent. It happens because most workshops do not have the equipment to measure an injector. They can read fault codes and look at return flow on the vehicle, and that gives an indication — but not an answer.
When you cannot measure, the safe recommendation is to replace the whole set. At least then you know the problem is gone. The bill is simply correspondingly larger.
On a test bench every injector runs through several test points that replicate real operation:
The result is numbers, not an opinion. And surprisingly often the numbers show that only one injector is outside tolerance.
An injector can deliver full output at full load and still be faulty. That comes down to pilot injection. A modern diesel injects three to seven times per power stroke, and the first injection is only 1–2 mm³ — the one that makes a diesel quiet. At quantities that small, even a few per cent deviation is felt as diesel knock.
If you only measure at full load, you will never find that fault. That is why we measure across the whole operating range.
DKK 250 per injector. A set of four costs DKK 1,000 to have measured, and you get a written report with it. If the injectors are fine, we say so and send them back — then at least you know the fault has to be found somewhere else.
