Is Used injector coding required?

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dylanrobs
still on the production line
Posts: 33
Joined: Mon Jan 06, 2014 10:59 am
Passat model: B5.5 130 Tdi Est
Location: Anglesey

Is Used injector coding required?

Post by dylanrobs » Sat Feb 17, 2018 9:23 pm

Hi guys,
I have an A6 3.0 tdi, 2005. Done a basic test on injectors (Yes I know they are poo, Bosch piezo type) and found 1 out of tollerance, which is causing a few problems for me. Has anybody replaced a faulty injector with an used one or know if you have to code the replacement injector?

New ones are around £200 + and dont want to start spending big money, hopeing this way can cure the faults.
Thanks

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desertstorm
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Passat model: B5.5 130 TDI AWX
Location: Cannock

Re: Is Used injector coding required?

Post by desertstorm » Sat Feb 17, 2018 10:07 pm

The injector coding provides the ECU with very accurate information about the flow capabilities of the injector being installed. It's not possible to produce injectors that are identical, so the figures in the coding give the ECU an indication of whether the injector fuels more or less than a "perfect" injector. Thus the ECU adjusts the injector duration so all cylinders get the same amount of fuel at all engine speeds.
The problem is that injectors wear and thus the coding will only really be valid on a new injector. Used injectors will have more leakdown and higher flows than a new injector.So the calibration info on an injector is fairly useless.
The latest ECU's actually age the injectors and add correction factors to simulate the increased flow that occurs.
This is why you should not alter the coding of an existing injector on VCDS if you aren't changing it. The offsets are reset as the ECU thinks it's getting a new injector.
I would be surprised if it's only 1 injector that's duff. Others may be on their way out too. If you have a decent diesel engineer near you then pulling the injectors and having them tested will give you confidence that you are changing the correct injector and all the others are good.
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dylanrobs
still on the production line
Posts: 33
Joined: Mon Jan 06, 2014 10:59 am
Passat model: B5.5 130 Tdi Est
Location: Anglesey

Re: Is Used injector coding required?

Post by dylanrobs » Sat Feb 17, 2018 10:42 pm

Thanks deserstorm for the reply. Ill book it in to my local Bosch specialist and see whats actually happening with all the injectors.
Much appreciated.

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