Injector Contribution/Balance Error Help Needed

[G_Mac]

Hi all, I need help sorting out a contribution/balance error in my 2008 A5 Quattro 3.2L FSI.

A couple of weeks ago I removed all the injectors and had them tested and cleaned. One of the injectors got damaged coming out so I bought a new one (Hitachi FIJ0035). After putting everything back together the car ran fine, but I could smell that it was running rich. After a couple of hours driving the check engine light came on. I plugged in VCDS and it said I had a contribution/balance error on cylinder 2. I assumed it was one of the old injectors so ordered another new one.

When the new one arrived I went to install it and discovered the injector in cylinder 2 was the new injector I had purchased before, so assuming it was faulty I went ahead and replaced it with the one that just arrived. I put it all back together and went for a drive. Once again it was running good but smelt very rich, then after half an hour of driving the check engine light came on again. A check of VCDS said it was cylinder 2 contribution again.

So I went ahead and took the new injector back out along with one of the old ones to use as a reference, and took them to the injector guy to test. They all tested fine but one of the new injectors has a lower output than our reference injector, and the other had a higher output.

I went back and put everything back together but this time put the new injector in cylinder 3. I also swapped the spark plugs and ignition coil of cylinder 1 and 2, did a compression test, and checked the electrical connections of each injector. I started driving and Groundhog Day... car ran fine, smelt very rich, check engine light came on, and VCDS said contribution fault but this time on cylinder 3. So the problem is definitely the new injector but it’s not faulty, it just as a different flow rate.

Can someone tell me how I fix this? I have a guy coming on Saturday to look at the car as I have it up for sale. I can’t sell it with the check engine light on. I reset the ECU which didn’t fix it. I have VCDS but can find any info on changing the flow rate of a single fuel injector. I’m stumped! Any help would be appreciated.

[Gosser]

When I was getting my B7 A4 3.2 injectors cleaned(for a hard starting issues), two of them needed to be replaced. My injector guy said to be careful since the flow rates of GDI injectors are typically performed in batches due to their sensitivity, and then the ECU adapts to them(or done from the factory). He said a lot of guys experience what you experience in just replacing one or two. He recommended getting all six new, in hopes that what they send are all from the same batch, but it is still, suppliers dont batch them when stocked, so still a shot in the dark. Ultimately, guys will have brand new injectors flowed to see their rates, and buy more as necessary. I thought this was crazy and reminded me why I still love my old port injection motors. I must have gotten lucky replacing just two of them, no codes like that came up for me. The hard starting issue was two of the injectors, and the car worked perfect for an entire year, now its experiencing just a slightly long start...

[DannyPhilips]

It seems to me that if after several manipulations the desired result is not achieved, you should drive the car to service - you should be able to stop in time.

[ngarry243]

Change injectors, and discard CHECK with ELM 327.