willowcreek

I recently purchased a 2010 535i. 100k miles. One owner. Appears to have been very well taken care of. Drove it home from Nashville Area and it ran great. A couple of days ago it began missing with moderate to heavy acceleration at about 2500 rpms. Gas mileage on the hwy was still pretty good but much worse in town. I removed both Vanos Solenoids, cleaned them and put them back on (free, so why not). Car now has a rough idle and actually threw the check engine light. Runs worse than it did. I had already purchased new spark plugs so I went ahead and put then on. No improvement. I don't have a BMW scan tool yet but will get one soon. I just have a pretty simple OBD reader and it shows no codes. Something I did with the solenoids made it go from slightly bad to worse. Planning to take it to my indy tomorrow but he is always backed up so I know it will be a few days before he gets to look at it. Without having codes, can anyone give me some ideas on what I might be looking at?

kd7iwp

I’m confused, I don’t see how the check engine light is on yet your scanner showed no codes. Did the light go off when you restarted the car?

willowcreek

Yes, it appears the code was maybe clearing when I turned off the car, or my OBD reader is not very good. However, I did re-scan and got code P052B

Chris Mac

Check to make sure you plugged in the right wires to the solenoids.
maybe you got the wires switched.
i did that when I changed the timing chain cover gaskets...scared the poop out of me!

willowcreek

Great idea and definitely something I could do, but bc I know myself so well I took a pic beforehand to make sure I didn't cross them up when I put them back. Thanks for the feedback though. I have it at my Indy shop today and he is going to take a look at it. He said that the adaptations sometimes have to be reset when changing or cleaning the Vanos Solenoids bc it can throw off the timing just a bit. We will see what he finds and I will report back.

Thanks for your feedback.

willowcreek

Well, it pains me to write this conclusion but I've decided after reading so many threads with no final conclusion that, in order to be helpful, I need to tell everyone how the car was fixed -- especially to those of you offering many helpful tips. And even if it comes with a large dose of embarrassment.

Took the car to my mechanic first thing yesterday morning and explained that I had removed and cleaned the Vanos Solenoids and car now runs like crap and has a check engine light. He's swamped but said he would do his best to get to it bc he knew I had a lot of business driving coming up this week.

He calls me yesterday afternoon and informs me it's ready to go. I get there and with a slight smile says you had the connectors crossed (exactly what Chris Mac suggested). I said that's impossible, I took a pic beforehand. So I go back and look at my pic (which was with the engine cover on and not a great angle) and I still cannot see the mistake. Bad pic, but why I did not put a piece of tape or in some way mark one of the connectors is beyond my small brain. Just got in a big rush not seeing how I could possible screw this up.

So, on the bright side, since my mechanic had it inside and knew it was a new-to-me-car that he hadn't seen yet, he took about 30 minutes looking it over and had already had the scanner on it. Gave it a quick once over and said it looked good and appeared to be well taken care of and maintained. Suggested I come back in the next couple weeks to let him change the transmission fluid and filter. Charged me $90 and I was out the door.

Now, the original reason for cleaning the solenoids was bc it had developed a slight miss upon moderate to heavy accceleration at around 2500 rpms. That does appear to be gone. I haven't driven it a ton but from driving it the 10 miles home and a little bit of additional driving I have not felt the miss upon acceleration. I did replace the plugs Sunday night so that could have helped as well, although the old plugs did not look bad at all. I definitely think they had been replaced before. So, I cannot decisively say it was the result of cleaning the solenoids.

Last thing, when working on the car Saturday evening in the garage my wife came out to see how it was going. She could see my frustration with the car now having a check engine light so I walked her thru everything I had done and she asked the expected questions: "are those 'things' pushed all the way in"? "does it matter which connector 'thing' goes on which one"? (well of course honey), "are you sure the connector 'things' are on the right one"? At which I gave her the "do you think I'm stupid look"? So, for now, my wife thinks that the car had a vaccum leak. In a few days I will tell her the truth but I just can't do it right now

spazzz

I love a happy ending.
Thanks for the solve.

audiophool

Rule 1: It was a vacuum leak. The mechanic found it. Never tell your SO you messed up, or she won't let you spend your weekends faffing around with the car in the garage, drinking beer. Trust me.