[WildWilly1100]

I should have tried this first rather than VANOS solenoids and cam sensor. I've been using seafoam for years in my motorcycle, it should have been obvious to me. Oh well, lesson learned.

[WildWilly1100]

Here is a video of a cold start this morning, 0° C / 32°. Maybe not, can't upload a video, but when I started this morning, it hit 1,200 rpm and stayed there for 20-30 seconds and then slowly dropped below 1,000. I would say problem solved. Hopefully, the plugs and SeaFoam idea will help someone else. Cheers...

[Bmwfan55]

Originally Posted by WildWilly1100

Thanks, I've already looked on ecs site. But this morning, she barely dipped below 1,000 rpm, so it is definitely getting better. ½ a tank to go, then fill up again with seafoam. Also, went for a drive yesterday using manual mode and kept it above 3,000 rpm on the highway for a while.

Did u use sea foam IC5? And how many times did you add it to tank?

[ryansbmw]

Originally Posted by WildWilly1100

I replaced the VANOS solenoids and it made no difference, talked to a top level MB tech and he says two things to do. 1) a good cleaning of the throttle body plates with the correct type of cleaner, sometimes they can get sticky with age, 2) go for the intake cleaning, start with a fuel system service, then go to walnut blasting if needed. Will look into these two things in the spring.

Originally Posted by Bmwfan55

Just replaced the camshaft position sensors, fresh oil change and vanos cleaning. I am amazed of how smooth the car starts on cold mornings! Hope this helps you

Thanks for the input. I forgot I actually posted over on this forum.

So like I said earlier, rough start on cold starts only. Colder the temp, the more likely it is to occur. The other week I had only gone a few blocks and the engine light kicked on but eventually went away after 10 min. Code “2D5A VANOS intake control fault, camshaft stuck” was logged. I took the car to the shop. They cleaned both solenoids and swapped positions. Car is running smooth but then a few days later the same code pops back up (stayed on intake side). Strangely enough both times the code has come up, the car was idling normally and seemed to be driving just fine.

This morning the idle was bouncing again for 15 sec, almost stalling out, before settling. No codes.

Can camshaft sensors cause VANOS codes? Maybe injectors? Maybe walnut blast? Plugs and coil were replaced last February, only 15k miles ago. Looked at fuel pressure after the car sat for a few days and that seemed fine during startup (the car did not have a rough idle during that startup tho- I’ll keep trying to catch it). Shop thinks it may be the actual VANOS unit itself which is $2k repair but won’t know for sure until they take the valve cover and other parts off 1st.

[ezaircon4jc]

This has been going on for a while and I don't remember; have you ruled out bad gas? Or water in the gas?

[ryansbmw]

I only use 93 oct gas from Sunoco, Mobile, BP, etc. so quality gas isn’t a problem.

Something about cold starts on cold days is the trigger. If the car stalls out while idling, or while the rpms are bouncing, restarting the engine will solve all problems and everything is normal

[SWFLf10]

Thinking back, I had a similar issue with my first BMW, a 2006 325i. It ended up being a bad eccentric shaft sensor. I believe it was a bit easier and cheaper to replace on that engine though, the N55 has the sensor and servo motor as one piece I believe.

Could be worth looking into and seeing if there's an easy way to check that sensor.

[Bmwfan55]

Originally Posted by SWFLf10

Thinking back, I had a similar issue with my first BMW, a 2006 325i. It ended up being a bad eccentric shaft sensor. I believe it was a bit easier and cheaper to replace on that engine though, the N55 has the sensor and servo motor as one piece I believe.

Could be worth looking into and seeing if there's an easy way to check that sensor.

Yea that's my next suspect. But I am done throwing money at the car chasing that issue. Car runs well besides the drop on cold start, so I'll drive it as is. It almost unnoticeable now that days are warmer.

[WildWilly1100]

Originally Posted by Bmwfan55

Did u use sea foam IC5? And how many times did you add it to tank?

Added it to two tanks of gas and now all is well. I always fill up with Premium and 95% of the time it is Shell.

[WildWilly1100]

Originally Posted by Bmwfan55

Did u use sea foam IC5? And how many times did you add it to tank?

Here is a pic of the stuff I used, not sure if it's IC5 or not. Been using it for over 10 years in my motorcycle and my '74 Fiat.

[WildWilly1100]

Originally Posted by ryansbmw

Thanks for the input. I forgot I actually posted over on this forum.

So like I said earlier, rough start on cold starts only. Colder the temp, the more likely it is to occur. The other week I had only gone a few blocks and the engine light kicked on but eventually went away after 10 min. Code “2D5A VANOS intake control fault, camshaft stuck” was logged. I took the car to the shop. They cleaned both solenoids and swapped positions. Car is running smooth but then a few days later the same code pops back up (stayed on intake side). Strangely enough both times the code has come up, the car was idling normally and seemed to be driving just fine.

This morning the idle was bouncing again for 15 sec, almost stalling out, before settling. No codes.

Can camshaft sensors cause VANOS codes? Maybe injectors? Maybe walnut blast? Plugs and coil were replaced last February, only 15k miles ago. Looked at fuel pressure after the car sat for a few days and that seemed fine during startup (the car did not have a rough idle during that startup tho- I’ll keep trying to catch it). Shop thinks it may be the actual VANOS unit itself which is $2k repair but won’t know for sure until they take the valve cover and other parts off 1st.

Sounds like what was happening to me, but I didn't ever get any codes. On the coldest days, it almost stalled out. My guy did run a camera into the intake and said the carbon build up was minimal (121,000 kms). So nothing to worry about there. The SeaFoam did the trick, probably would have cleaned up my plugs, but I'm glad they've been replaced. Check ECS Tuning for VANOS solenoids, 2K seems like a lot, especially in the US. I think I was about $700 CAD all in. After market solenoids, of course. Genuine BMW parts are crazy money.

[WildWilly1100]

Originally Posted by Bmwfan55

Yea that's my next suspect. But I am done throwing money at the car chasing that issue. Car runs well besides the drop on cold start, so I'll drive it as is. It almost unnoticeable now that days are warmer.

I hear about chasing the issue, I did the VANOS and the cam shaft sensor, didn't need to do them. But I'm glad it's sorted out.

[ryansbmw]

Originally Posted by SWFLf10

Thinking back, I had a similar issue with my first BMW, a 2006 325i. It ended up being a bad eccentric shaft sensor. I believe it was a bit easier and cheaper to replace on that engine though, the N55 has the sensor and servo motor as one piece I believe.

Could be worth looking into and seeing if there's an easy way to check that sensor.

I’ve heard that too. Pulled the plug and it was clean as a whistle. Seems like some people who have had problems here have oil and crap in there. Not getting any codes pointing towards that either. Hard to drop money on some of these more expensive repairs when I’m basically shooting in the dark

[ryansbmw]

Originally Posted by WildWilly1100

Sounds like what was happening to me, but I didn't ever get any codes. On the coldest days, it almost stalled out. My guy did run a camera into the intake and said the carbon build up was minimal (121,000 kms). So nothing to worry about there. The SeaFoam did the trick, probably would have cleaned up my plugs, but I'm glad they've been replaced. Check ECS Tuning for VANOS solenoids, 2K seems like a lot, especially in the US. I think I was about $700 CAD all in. After market solenoids, of course. Genuine BMW parts are crazy money.

$2k was for replacing the actual VANOS units, not the solenoids. The shop cleaned and swapped the solenoid positions but the code didn’t move from intake to exhaust so the solenoids appear to be fine. I’ll try the sea foam and see if that helps. I used it on my old Acura Legend and I couldn’t believe the amount of smoke coming out.

Is seafoam all that different that Techron fuel system cleaner? I’ve run a few bottles thru the gas tank with that already with no change

[Bmwfan55]

Originally Posted by ryansbmw

$2k was for replacing the actual VANOS units, not the solenoids. The shop cleaned and swapped the solenoid positions but the code didn’t move from intake to exhaust so the solenoids appear to be fine. I’ll try the sea foam and see if that helps. I used it on my old Acura Legend and I couldn’t believe the amount of smoke coming out.

Is seafoam all that different that Techron fuel system cleaner? I’ve run a few bottles thru the gas tank with that already with no change

Yeah I have used Techron una the past. I will give seafoam a chance.

[WildWilly1100]

Originally Posted by ryansbmw

$2k was for replacing the actual VANOS units, not the solenoids. The shop cleaned and swapped the solenoid positions but the code didn’t move from intake to exhaust so the solenoids appear to be fine. I’ll try the sea foam and see if that helps. I used it on my old Acura Legend and I couldn’t believe the amount of smoke coming out.

Is seafoam all that different that Techron fuel system cleaner? I’ve run a few bottles thru the gas tank with that already with no change

My mechanic suggested SeaFoam or the Lucas fuel system cleaner, those are the only two he will use. I don't know anything about the Techron one. Keep us posted if you are able to solve the problem.

[Bmwfan55]

Originally Posted by WildWilly1100

My mechanic suggested SeaFoam or the Lucas fuel system cleaner, those are the only two he will use. I don't know anything about the Techron one. Keep us posted if you are able to solve the problem.

Now that nice weather has arrived to NJ, my car starts without issue. I think I will never be able to find the cause of the rpm drop on cold start, during the winter time. Freaking car is so temperamental!

[ryansbmw]

Originally Posted by Bmwfan55

Now that nice weather has arrived to NJ, my car starts without issue. I think I will never be able to find the cause of the rpm drop on cold start, during the winter time. Freaking car is so temperamental!

Haha same thing here! Where in NJ are you?

[Bmwfan55]

Originally Posted by ryansbmw

Haha same thing here! Where in NJ are you?

Bergen county. Friggin car is running money now

[vapormike]

Originally Posted by arshakadelic

Are you shifting to reverse right away ? Mine does that when I'm in a rush and put it into gear right after a cold start. I've stopped since and it's been fine.

I had this happen to mine and found that its the transmission and not the engine. Got an update to the transmission software and it stopped happening.

[Bmwfan55]

Originally Posted by vapormike

I had this happen to mine and found that its the transmission and not the engine. Got an update to the transmission software and it stopped happening.

That's interesting. I'll look into that. Sweet ride btw

[WildWilly1100]

Originally Posted by Bmwfan55

That's interesting. I'll look into that. Sweet ride btw

That's good to know, as it's started happening again after two weeks of being OK. Doesn't drop below 1,000 rpm, but it does drop and then go back up.