Post Piston Soak with Berryman B12

We are back, sorry for the wait! Ok let get right into this. The soak went awesome, but afterward well it was up and down. 

First, the before and after of the cylinder 3 is night and day! Before there really is only two patches of  bare metal. Post soak (day 5), my cheap borescope was overexposing as it was actually shiny inside. That's a win right there!

I went a little crazy as this was a 5 day process. 1st day I added 50ml Berryman B12 (affiliate link) to every cylinder and manually rotated the engine and just let it sit for the rest of the day. First day was like a pre soak and Day 2 I would put two pistons in TDC (top dead center) and 50ml of B12 in each of those cylinders. The other 4 cylinders I went in and sprayed Gumout 540028 Foaming Intake Valve & Turbo Cleaner (affiliate link). The thought was to keep every wet and since this foamed up really good I wasn't fighting gravity to get the full cylinder wall and piston covered. Between each 24hr cycle I would use compressed air flush out each cylinder, then manually rotate the engine for a few min. Then I have my next set of cylinders at TDC, add 50ml of B12, Gumout sprayed to the other 4 and soak for 24hrs. Repeat for the last set on day 4.

On day 5, I did the finally compressed air to flush everything out and let each cylinder air out for a few hours. While that was happening I drained the oil and installed a new oil level sensor. Now in the piston soak video (https://www.youtube.com/watch?v=7aY1yDxSiJw) they suggest not to drain your oil immediately, but I think I used far more b12 with the day 1 pre soak, so I did not want the oil to thin out too much. As well I'm only 2 months into this car loan and don't need a failed motors (possible foreshowing here). So new oil, new oil filter before the first start

Should I have rolled the Q7 out garage, yes, but I was home alone, excite and wants to see it running again. It was a smoke show for sure, but I was expecting it. Took about 30mins for it to really clear up. At this point it was mid December and we had some holiday gatherings to get too. We all jump in and took it for a good hour ride and no issues. 

Fast forward a few days, we are all commuting home. We are on the freeway doing 60mph and I want to open her up.. and massive misfire. Scanned with OBDEleven (affiliate link) and cylinder 1 & 3 are getting Air-Fuel Ratio Imbalance (P219E00). I'm immediately thinking we lost compression engine is done or if I'm lucky two injectors just went bad. I drive home as carefully as possible but no misfires are felt. 

Next day, pull the plugs, clean them, regap them, get out the borescope and peak around. I can't really find anything so just put everything back together, clear the code and hope for the best. Take it for a test drive and watch the misfire count on on OBD11. Nothing on 1 but a few misfires on 3 but never felt them. Cyc 1 code never came back after this point. This feel more like a bad fuel injector on 3 is more of the issue and 1 was a false positive. Drive it around for a few days and the Check Engine would come back for cyc3. I added a left over bottle of B12 in to the fuel tank and just pray it will clean the problem injector. We put about 300 miles over the course of 3 days just trying to get as much mileage as possible to see if the issue would clear up... but it didn't. Our plan like we do every Christmas was to drive about 5hrs to stay with family, but we were out of time. No way to get parts and install them and test the Q7 to make sure it was good before a long trip... and no way we all could fit in the S4. It hit pretty hard not being able to hang out with family. I ordered injectors for the direct injection and port sides and they arrived after xmas. 

Over the holidays I keep looking around and accidently hit the side camera button on my borescope and saw the injector. Started comparing with other injectors and Cyc3 certainly had more carbon buildup over it. Could we really just being getting a bad spray? I ran another bottle of fuel injector clean and we just drove it like we stole it for a few weeks. I would clear the code but it would come back 2-3 days later. Come Jan 7th I get a text from my wife asking if I cleared the code and I hadn't. The CEL went off on its own which is a really good sign here.

Fast forward another week and ​I happy to report still no check engine light. During the past few weeks of honestly regretting this Q7 purchase I completely forgot about why I did all of this, the stupid oil consumption! There hasn't been any! We are nearly 1k miles post piston soak and haven't had to add a drop of oil. Prior, I would have needed to add at least 2qt by now.

What caused the Check Engine Fault? 
Honestly I'll likely never know. 

Theory #1: I might not have blown out Cyc3 good enough post soak and or the b12 wasn't fill high enough to clean out the carbon around the injectors. So using more fuel injector clear in the tank help clear a path around the injector. That said I would expect more misfires if that was the case.

Theory #2: The piston rings on Cyc3 were still slowly breaking free and while the rest of the bank the compression was already improved. AKA Cyc3 air/fuel was out of balance because of a lower compression. Going with the method of just driving it hard just help finally free the piston rings to bring the compression back up may have done the trick. Note, I'm 100% guessing here as I didn't compression test it. Yes I should have, but I started fearing that it was leaking intercooler blocks and that distracted me. Thankfully a pressure test of the coolant system put that fear to rest. 

At this point the Q7 is back and on the road. Up next is a brake job, transmission flush, and new motor mounts. Will wait until spring for that. Happy new year!