How to identify EU5 V.S EU6 Injectors.

BMW fuel injectors have been a hot topic for many owners over the last decade or so. The switch to direct fuel injection made BMW’s N5X and B5X-series engines some of the most capable Euro tuner platforms of all time. However, their initial Piezoelectric-style injectors were anything but reliable and left owners footing a large bill. A switch to a different Bosch unit solved both problems, but then the EU updated its emissions regulations, forcing another update. 

The Bosch HDEV5.2 direct injectors are a much more cost-effective solenoid style than the Piezos they replaced, but choosing the right one can be a challenge. The switch from EU5 to EU6 regulations forced an update to the injector, making the two injectors incompatible. It also happened in the middle of a model year, eliminating any easy distinction about which models carried which injector. Unlike other mid-year changes, the VIN won’t tell you either, so you’re left with a few options.  

Identifying Your BMW EU5 or EU6 Injectors

Because the VIN doesn’t help, you cannot rely on readily available sources like RealOEM or Bimmercat to look up the injector part numbers. In fact, these sources give you a warning which looks something like this:

"Attention: Injector conversion from EU5 to EU6. In case of several injector options, before replacing the injector the >injektor determination< service function must be called up and the designated injector ordered. 
For vehicles from 01.07.2013"

This warning can be deceiving, though, because it makes it seem like you can switch to different injectors, and that's not the case. If your vehicle has EU5 injectors, you must replace them with the correct EU5 injectors. The same goes for EU6 injectors. The warning states that you need to identify which injectors your BMW has. BMW has a process for this centered around the use of ISTAD, and it looks like this:

Identifying EU5/EU6 Injector Type Using The BMW Test Plan

1. Determine the type of injector installed in the vehicle using ISTA/D 4.04 or later test plan using the following path:
   - Identify the vehicle automatically.
   - Select “Vehicle management”
   - Select “Service functions”
   - Select “Powertrain”
   - Select “Engine electronics”
   - Select “Injector determination”
2. Follow the test plan prompts. At the conclusion of the test plan, it will state one of the following:
   “This engine requires EU5 injectors”
   Or
   “This engine requires EU6 injectors”
   Close the diagnostic session to transmit FASTA Data.

That may sound simple, but it doesn’t mean anything if you don’t have access to ISTA. Luckily, the good news is injector identification can be determined using many aftermarket scan tools like the Autel MX808 or the Autel AP200. Alternatively, you can manually identify the injectors by removing engine covers and checking their part number. All of these injectors will be labeled with a Bosch number (10 digits) and the BMW number in its short format (7 digits). That process is tough to explain in writing, but the good news is we have a video that explains it in its entirety which you can see here:

BMW EU5/EU6 Injector Identification Chart

N55

N26

N20

N63TU & S63TU

S55 

Coding BMW Injector Quantity Compensation

You must perform an injection quantity compensation after replacing any of these injectors. Even if the adjustment value is the same on the new injector as on the original, it’s still required. Failing to set the compensation value can lead to rough running or a refusal to start. 

The process in which you enter/make this adjustment will vary by the scan tool being used. Aftermarket scan tools such as the Autel MX808 and Autel AP200 can perform this service function. The steps to perform this adjustment are very straightforward.

The adjustment value is printed in three digits on the injector body. Whether replacing a single or all injectors, recording the number from the injector with the corresponding cylinder is a good idea. After finishing the work, you can reference this information for the injection quantity compensation adjustment.

Here is the injector quantity compensation adjustment value:

Here is a video where injectors are being calibrated on an N20 engine using an Autel MX808:

Once you've figured out which injectors you need, put your vehicle's information into the "My Garage" portion of our main site and use the above part numbers to find the right injectors for your BMW engine. We also sell the tools required to remove the injectors from the cylinder head, so grab those, too, if you're following our DIY! As always, keep an eye on the blog for more entertaining and helpful written content, and follow along with our YouTube channel for the best European Automotive content around.