[Ryanfknt]

Originally Posted by acarpenter86

Did you ever get it figured out? Hopefully it was not the ledge wear.

I'm 'finishing up' an f10 project. Long story short, I got it dirt cheap, it had sucked a belt, I cleaned all traces including oil pickup, etc (I have done this job several times), new valve cover, fixed all oil leaks.

Unfortunately I am getting Vanos codes on the EXHAUST side (code 0304 exhaust camshaft stuck and once in a while the cold start counterpart). I cleaned and swapped solenoids and also operated them while cleaning with a 9v. Even swapping them it is the exhaust code. Engine purrs like a kitten... but it is in limp mode after short drives. While running at idle, ISTA says 10.5 degrees for exhaust and 8 degrees for intake (both are approximations). Is that high? I can't seem to find the 'normal' degrees with my Google fu. If those ARE high, that makes me think the belt wrap threw timing off just enough to screw things up.

If those degrees can be considered 'normal' my next thought is to try an adaptations reset and perhaps update the software. Then I guess I am opening of the valve cover again...

i had the vanos adjusters / sprockets - reversed. I actually broke the black cap off the oem one like an idiot because i wanted to take it apart and look at it. Then i bought a china set off amazon and installed those. codes were gone but the car was not running right. Then i pulled the valve cover back off and set timing again using the oem sprockets (one without the cap on it - fuck it.) RUNS PERFECT NOW no more codes.

just buy the two sprocket bolts (one time use), set the timing using a dial indicator, and slap the valve cover back on. its only a 3hr job. i did it like 5 times

[acarpenter86]

Originally Posted by Ryanfknt

i had the vanos adjusters / sprockets - reversed. I actually broke the black cap off the oem one like an idiot because i wanted to take it apart and look at it. Then i bought a china set off amazon and installed those. codes were gone but the car was not running right. Then i pulled the valve cover back off and set timing again using the oem sprockets (one without the cap on it - fuck it.) RUNS PERFECT NOW no more codes.

just buy the two sprocket bolts (one time use), set the timing using a dial indicator, and slap the valve cover back on. its only a 3hr job. i did it like 5 times

Thanks to you both. I did not receive notifications that you both had responded. I am glad you got yours running, Ryan! I'm starting to think mine has to be timing. My theory is when the previous owner lost the belt, it slightly disrupted timing on one or both cams relative to the crank due to ingested belt material, but we shall see. You're right- getting the valve cover off and back on is not too hard after "practice" LOL.

Originally Posted by Stu Blue Car

One big mistake i made was buying cheap aftermarket sprockets. They stuck. I ended up buying 2 new bmw sprockets but the exhaust kept giving me a code. I needed the intake as the spring started coming loose and interfering with the cam position sensor. I put the original exhaust sprocket on with the new intake sprocket . And the dial gauge to confirm tdc on the crank. I think in the end, confirming the tdc was the most important.

So, you had put both of the new sprockets on and STILL got the code? Then you put the original exhaust one back on with the new intake? I guess if I am reading correctly, you are thinking while both new ones were on, the timing was still slightly off?
Thanks for the explanation on the biasing. I will try to do that as well.

[acarpenter86]

Alrighty, I have the valve cover off and am checking things out. As I understand it, while the engine is off, the cam adjusters should lock in place if I rotate manually. So that is one failure mode to check, assuming things appear to be in time- try to rotate cams while locked in TDC. If there is movement, an adjuster has failed or at least stuck. After ruling that failure mode out, if I remove the TDC pin and rotate by hand and it stays in time, should I pin it again and remove the exhaust Vanos adjuster sprocket and see if it is worn internally? I found a video and it does not look very complicated to disassemble.

I got excited at first because when I popped the valve cover off the cams were slightly out of alignment (amazingly the engine was just behind TDC already) but I think once I manually advanced the engine to pin it, the cams fell back into correct TDC position, which makes sense as last time I had the engine running it probably was adjusting timing and then when I turned off the car things slide a bit. Then presumably when you start it, both units should pop into 'locked' position on those adjusters.

Hope that all makes sense. I am set on learning how this works and fixing it in a logical order. I am confident I will get it running properly.

[acarpenter86]

I am waiting for my timing tool to come in. I checked with my n52/n54 tool (as much as I could) just to see how things are looking. I’m 100% positive I’m in the correct TDC as I found it visually with a scope, also with a screwdriver, and it is nice and locked with minute play.
I also made sure the chain tension is “tight” against crankshaft and then between both cam adjuster units/cogs.

I am finding the exhaust camshaft to be slightly in retarded position. It’s hard to tell in my photo, but the intake side of the alignment tool goes on, the exhaust isn’t aligned enough to slide down.
Have I found the issue (slight timing loss, probably from belt wrap) or should I be looking at a replacement VANOS adjustment unit? I think it’s locked in, but somewhat hard to tell as obviously if I try to advance it I just introduce slack into the chain.

[Stu Blue Car]

Don’t be fooled if the cams are not perfect when you slide on the tool. They should be moved into place.

[Stu Blue Car]

Originally Posted by acarpenter86

So, you had put both of the new sprockets on and STILL got the code? Then you put the original exhaust one back on with the new intake? I guess if I am reading correctly, you are thinking while both new ones were on, the timing was still slightly off?
Thanks for the explanation on the biasing. I will try to do that as well.

I did this at least 6 times too. My biggest issue was crank tdc. I swear there is a spot the pin can go in that is close to the correct hole.

[Bmw turbo]

Its really simple to take apart the vanos unit. If you are in the engine already, might as well rule that out. The only “hard” part will be putting the spring back on afterwards. It only took me a couple minutes to do it by myself, with just a pair of pliers. If you will take it apart, check if it is full of oil.

[acarpenter86]

Originally Posted by Stu Blue Car

I did this at least 6 times too. My biggest issue was crank tdc. I swear there is a spot the pin can go in that is close to the correct hole.

That makes sense! I found my TDC with borescope and as well a screwdriver in cylinder 1. My flywheel has a piece welded on that makes it super obvious. I used a 7mm Allen wrench and it is definitely locked in.

Thanks to your photo from ISTA, I may be eliminating the possibility of timing being off. It is super close to sliding on and I could definitely force it. This is after turning the engine over one full revolution to see if the VANOS unit was bound or anything since the chain would go slack if I tried to advance it.

Originally Posted by Bmw turbo

Its really simple to take apart the vanos unit. If you are in the engine already, might as well rule that out. The only “hard” part will be putting the spring back on afterwards. It only took me a couple minutes to do it by myself, with just a pair of pliers. If you will take it apart, check if it is full of oil.

Noted! I plan to take the exhaust unit off for sure and see what is going on inside of there. I take it it SHOULD be full of oil, right? (activated by oil pressure...)


At this point (thanks to the above ISTA screenshot), I am thinking (hoping!) it is the VANOS unit. If not, I guess I am going to have to pull the exhaust camshaft shell off, which I would love to avoid...

[Bmw turbo]

Correct. It SHOULD be full of oil. From what I understood, your code is for vanos being stuck, not your timing being off. I’m wondering if either some oil line is still clogged or the vanos unit itself is bad. Did you check your oil filter housing cage? If the cage or the small o-ring is missing, that could also cause the vanos not to work properly.

[acarpenter86]

Originally Posted by Bmw turbo

Correct. It SHOULD be full of oil. From what I understood, your code is for vanos being stuck, not your timing being off. I’m wondering if either some oil line is still clogged or the vanos unit itself is bad. Did you check your oil filter housing cage? If the cage or the small o-ring is missing, that could also cause the vanos not to work properly.

I got the VANOS unit off today. It was full of oil when I took it apart. It didn't seem to have excessive wear, but I broke one of the four bolts upon reassembly (which makes me think even though no open recall that these are the failure prone bolts) so I just went ahead and ordered a low miles exhaust unit to try.

The unit made some weird sounds when I was unbolting it, so maybe it is hanging.
The oil filter has the proper cage and o rings...

Hopefully it isn't ledges. Is it possible that timing being slight off can throw the exhaust sticking code?

[Bmw turbo]

If your car had a problem with timing, you would have gotten a code that the timing is advanced or retarted with respect to the crankshaft(or any timing-being-off related code). The code that you are getting is related to either the vanos unit itself being bad, or not enough oil pressure for the vanos unit to operate properly.