Injectors
No two injectors are alike. Even within the same part number the injection quantity varies enough that the engine management needs to be told.
That is why the manufacturer measures every single injector at the factory and engraves a code on it. At Bosch it is called IMA. At Delphi and Denso it is referred to as a klassifikationskode eller C3I. Koden beskriver præcis den dyses afvigelse ved en række testpunkter.
The ECU uses the code to correct the opening time for each individual cylinder. Two injectors that open marginally differently get different control signals — so all four cylinders deliver the same.
If you fit a new or reconditioned injector without writing in the new code, the ECU still compensates according to the gamle dyses tal. Resultatet er:
That last point is worth noting. A cylinder that consistently gets too much fuel runs hotter than the others — and that is how a piston is destroyed over time.
On most newer vehicles the coding alone is not enough. You also have to run an adaptation, where the engine management learns each injector’s real behaviour over the first operating cycles and fine-tunes to it.
Without both coding and adaptation the job is not finished — however well the injector itself has been reconditioned.
It requires diagnostic equipment that can write to the engine management, and very few generic OBD readers can. If you have had injectors reconditioned by us and fitted them yourself, you are welcome to drop by and have them coded.
