Update: was able to change one bad injector succesfully. Dealer prescribed changing all Bank 1 injectors and plugs for $2400. I suspected I only needed to change one as only one plug on Bank 1 was fouled and, after I ran ISTA misfire test it was 35,xxx versus 1,2,4 cyls were in the 4-digit or low teen 5-digit values. I was lucky that my 2011 had Index 11 injectors so I only had to change one. Total cost for everything? <$200
- Download a copy of ISTA - search via google you will find multiple links - get the latest 'working' copy. I only had a 256GB SSD on my laptop and with Windows 10 I did not have enough space to store all the files locally so I purchased a 1TB USB3 HD from Best Buy for $50.
- Purchase a BMW ENET cable and a USB<->Ethernet adapter unless your PC has an ethernet port. I got a cable from Amazon (read the reviews!) for $20 and the adapter for another $10. Worth noting the first cable I got only worked a few times and then stopped connecting via ISTA...garbage.
ISTA has a built-in diagnostic for the injectors that will do a leak down test and a more thorough individual exam. This has to be done when the engine is COLD. I did a warm test just to prove this and it told me the entire Bank 1 and one injector from Bank 2 needed to be changed. I did it cold and it only came back with Injector 2.
*** If you have injectors with Index 10 or lower, ISTA advises you will have to replace all injectors in the bank where 1 or more have failed. If you have Index 11 or higher, you can replace one or more single failed injectors.
If you buy injectors from the dealer, use part # 13538648937 which is about half the cost of 13538616079 which is what is listed on RealOEM and the dealer will try to sell you. The dealer will sell the -37 part number as it is a 'saleable' item but was designed to be purchased in sets. FCP Euro has an article on this:
https://www.fcpeuro.com/blog/posts/d...nd-13538616079
Purchase page:
https://www.fcpeuro.com/products/bmw...or-13537585261
There is a guide in ISTA that will walk you through changing injectors. There were numerous steps that I did not find were necessary but I encourage you to follow the procedure closely. The entire process took several hours.
Once you change injector(s), you will need to use ISTA to reset fuel adaptations and also code the new injectors based on the numbers listed on each.