2001 BMW 540i with P0021 Code

[Matt.tez]

Hello fellow enthusiasts, today I bring my troubles to the forums after only reading them all passively for many many years.

My 540i had timing chain guide failure in late fall of 2022 while in college. Long story short, we installed new Timing Chain Guides, OSV, Chain Tensioner, and Chain and have been having issues with P00X1 codes popping up after every reassembly. What could we be doing wrong?? We are using OEM BMW timing blocks and tools to make sure everything is in line. We cross reference repair manuals with German Auto Solutions (GAS) timing chain replacement guide and torque everything to spec as the book says. First time it was Bank 2 overadvanced. 2nd time it was Bank 1 overadvanced. The third time we torqued the chain tensioner to .7N/m instead of finger tight as GAS says and didn't have any errors until 800 miles down the road. Now I'm back in my college town and stuck with a P0021 (Overadvanced Bank 2). It may be important to mention that the car is currently tuned by Chaos Calibrations, and now has a fresh M62 non-vanos intake manifold installed at the same time as the new guides. My Vanos has also been rebuilt with Beisan Seals a few thousand miles ago. I don't think any of these three items could cause the car to misbehave as I had 800 miles problem free. I am on 91 octane so it's not due to bad gas. My CPS should be good, my Vanos Solenoids should be good. My research leads me to believe this is a cam timing fault before the vanos is activated.

I have cleared the light through INPA and reset engine adaptations and noticed that when starting the car after that, it idles smooth as butter. Once I rev it slightly, it starts to run as if it was cammed. It is definitely under power while driving but it runs closer to how it should once it gets in the upper rpm's. (3500+)

I am almost certain at this point that I am going to have to take the valve covers off and probably retime the car for the 4th time, but I would like to know if there is anything that I need to look out for? What could be causing the car to keep losing its time? Should I say screw OEM tools and borrow a GAS kit? This is my daily driver and I'm trying to get it back out on the road. Thanks!

[JimLev]

Welcome to the forum.
What timing kit did you use?

[Matt.tez]

OEM BMW Timing Kit. Got it from the Dealership

[capebmw]

Prepare to be tutored/taught by the wizard@jimlev. I will chime in with my my meager experience. There is lot's of chatter about the OEM vs GAS timing tools. Jim loaned me his OEM years ago, and I found them a little sloppy, but I am sure that was operator error since Jim has used them multiple times with success. I bought the GAS ones and find them fool proof.
Couple of things to look at. When tightening the VANOS bolts, make sure you use the proper torque and to hold the cams with a back up wrench. This is all in the GAS/Beisan instructions. The other thing I find crucial is to rotate the motor at least 2 times, if not more once you do the timing, then recheck with the tools to make sure all chain slack, etc has not altered it. I am sure Jim will talk about tweekng the timing wheels thru the hole in front of the covers to adjust a degree or 2 one way or the other. Keep us posted on here.

[R Shaffner]

I had a similar code on one side. I was pretty sure the cams were adjusted right (no slippage from a loose bolt). Adjusting the trigger wheels slightly solved it.

[Matt.tez]

Did adjusting the trigger wheel solve the problem fully or just put a "bandaid" on it to get the CEL off? I've heard of people doing that with the trigger wheel but was naturally suspicious. This car sees high rpm's from time to time �� so I would like to keep my engine internals intact lol

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Anybody have any input as to why it would act up after 800 miles though? Everything was torqued to spec and double checked.

[JimLev]

For your first 800 miles your trigger wheel was on the edge of OK/not OK.
So when the DME checks everything if your less that 5º off (cam) it will pass. If you are 6º off you fail.
Cam sensors and vanos solenoids have different codes.
A few degrees is maybe 1/8” of rotation. I’ll dig up more info and be back shortly.

[JimLev]

Watch this.
https://www.bimmerforums.com/forum/s...a-540tu-engine


Here's some cam code info....
On startup, the system tests the electrical integrity of the vanos solenoid and wiring. If they fail, code P0010/20 is set and the testing ends with both vanos disabled.

If the electrical test passes, then the DME checks the timing between the crank and cams. If more than +/- 10 degrees (crank), code P0011/21 is set, testing ends and the vanos disabled.

If the first two tests pass, the system bumps the intake cams advanced and watches for the change to happen in the allotted time. This time is 4 seconds. If the cams don't budge in 4 sec from the full retard position, a code P0012/22 is set.

[Matt.tez]

So if I'm understanding correctly, this is not a trigger wheel issue where I solely need retard bank 2 a few degrees counter clockwise. This calls for an entire retime with both banks blocked down. Right? If so, it's time I order some tools.

Thank you for your patience

[JimLev]

If you had the crank pinned and the cams locked down then the static timing was correct providing that the lock blocks didn’t lift off the back of the heads when you were tightening the vanos bolt.
Sure sounds like a trigger wheel issue to me.

What was the p/n of the timing kit you purchased from BMW?

[TiesTorN]

what a pita... I remembered the days when I struggled with this problem (last year)

fortunately mine was a simple problem. I don't know how it happened but I noticed one of the banks timing was off. retimed it and no problem since.

[Matt.tez]

If you had the crank pinned and the cams locked down then the static timing was correct providing that the lock blocks didn’t lift off the back of the heads when you were tightening the vanos bolt.
Sure sounds like a trigger wheel issue to me.

What was the p/n of the timing kit you purchased from BMW?

To be honest, my dad has worked there for like 20 years and I'm friends with most of the workers there so we just borrowed it lol. Unsure of P/N. Thank you for this info! I'm going to try and retard the trigger wheel 1/8th of a turn counter-clockwise on bank two and see where it leads. Making sure I mark start and end position. Hopefully it resolves the issue as everything was indeed blocked down and crank was pinned when timing was set to spec. I will update when I try it.

[JimLev]

NO, not an 1/8 of a turn......1/8 INCH

[Matt.tez]

Sorry! Misread ��

[Matt.tez]

Alright! Well this weekend I finally had some free time to work on getting that trigger wheel idea done. It was my first time doing everything on my own so it took a little longer than it probably should have but I got it done.First, I swapped CPS just to make sure it was nothing small but the P0021 code did not follow. Next I removed everything to get to the valve covers on bank 2 (driver side). Turned the car's wheels to the left to be able to slip in the pin at the crank so the engine is at TDC. Sharpied a section of the Vanos behind the trigger wheel and marked where I should start and finish by making scratch mark with a pick after measuring 1/8" with a digital caliper. I removed that alignment bolt at the top of the timing cover that I believe is supposed to show you if that trigger wheel is aligned. Visibly, it was indeed off by roughly 1/8th to 1/6th of an inch and in the CW direction so I had to rotate it CCW to get it to align properly. Counterheld the crank and loosened the 24mm nut. Adjusted trigger wheel and had it held in place with an allen wrench to ensure it did not move. Tightened it back up and put it all back together. I turned ignition on, cleared the light, turned it off and on and to my surprise, not only did I not fix the P0021 code, I now also have a P0011 code lol..... I did not touch timing at all on that side so it is beyond me that it even got affected by a trigger wheel adjustment.

I guess my next question is "what now?" I'm going to assume it's time for a full "block down" retime considering what I did, did not fix my issue. :/
Any advice appreciated. Also here are my pics since I was quite proud of myself for tackling this job even if it seems easy for many. This is the deepest I've dug into my engine on my own without help from my father. 69724786073__62F73F5B-644E-4A87-85CB-61EC36138BCE.jpg

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Also, if you cannot tell, I am a sucker for thorough and well explained blogs. Maybe because it's what I grew up reading all of these years. *shrug*

[RsRichard]

Did you put the alignment sockets on the cams when doing the above? The cams need to be fully aligned with the sockets - you can completely ignore the lock-bolt in the flywheel. Once the cams are aligned, execute same procedure as above again.

Error code / procedure above tells me you did not align cams but only crankshaft - which will never work out

[capebmw]

Me thinks you need to just start over and re-time it. And I will repeat, do the 2-3 complete revolutions once you initially time it, than go back and install all timing tools to verify nothing has moved.

[RsRichard]

A re-alignment of the position wheels will be sufficient here - but requires to apply the alignment sockets on the cams. This was a mistake to do it without.

[JimLev]

I don’t use the holes in the upper timing cover.
Put the engine back to TDC with the #1 cylinder on the compression stroke, install the cam lock blocks, then see if the trigger wheel alignment tools will verify the trigger wheels are set correctly. If not readjust them.
Then remove all the tools, turn the engine over 2-3 times like capebmw suggested, put all the tools back on to make sure the trigger wheel holes still align with the tools.

[RsRichard]

As the signal is coming from the Camshaft sensor which is located in the timing cover and can vary slightly in position due to the amount of pressure you apply when tightening the timing cover down it always makes sense to use the holes in the timing cover to get 100% alignment between sensor and position wheel. I agree that in most cases it is sufficient to only use the alignment tools - but I have done so many m62TU enginges that out of experience I can tell you it saves you a LOT of time, to simply verify that the hole in the timing cover aligns to the hole in the position wheel. This is 10 times faster than reopeneing the engine.

And for this certain case here I see this is his entire mistake: he tries to align the position wheels by locking the flywheel in position - not the camshaft. Which will never work due to the camshaft freely rotating within the Vanos unit as long as not locked via tool.

[Chedley]

Before you start the tear down for re-timing, could you hook up INPA, start your engine and monitor the Vanos angles LIVE (click on Engine status, then F6) . You will see how many degrees the Vanos angles are advanced (negative values) or retarded (positive values) on each Bank.
Then you can adjust your trigger wheel’s accordingly and precisely: CCW if advanced, or CW if retarded.

I am having a similar problem but only on Bank-2 with code 34 (hex P22) We can compare notes how that works, short of retiming the whole damn shebang….

[RsRichard]

This won't fix the issue as the DME is always diagnosing the position wheel timing against the CRANKshaft position - therefore the position wheel needs to be timed against the CAMshaft being in DTC lock position via alignment tools while position wheel is locked via pin in timing cover which determindes DTC CAMshaft position. On the M62 you always need to set the positions of the camshafts, the vanos AND the crankshaft in relation to diagnose where the issue resides. From the description above his camshaft timing is totally fine while simply the position wheels are off.

@chedley: same for yours BTW - error code 34 is always a 100% accurate indicator for the position wheels being off by about 1-2mm. Mostly due to timing chain cover not being pressured downwards while tightening to cylinder head.

[Matt.tez]

I donÂ’t use the holes in the upper timing cover.
Put the engine back to TDC with the #1 cylinder on the compression stroke, install the cam lock blocks, then see if the trigger wheel alignment tools will verify the trigger wheels are set correctly. If not readjust them.
Then remove all the tools, turn the engine over 2-3 times like capebmw suggested, put all the tools back on to make sure the trigger wheel holes still align with the tools.

Because I now have an over-advanced code on BOTH banks instead of just one, this means I have to do it to both sides now don't I? Not that big of a deal, I know how to do the job now (in terms of removing everything lol). I do need to buy my own set of cam blocks now since I am no longer home and Lubbock, Texas doesn't have jack over here...

Here is my plan: (helps to write it down myself so I can make sure I understand the process before I get myself in a mess)
Going to remove spark plug in cylinder 1
Turn crank until I see cylinder 1 is at TDC and can verify with markings somewhere on the engine or potentially crank hole slot.
Verify cam timing is good on BOTH banks with purchased cam blocks set in place.
At this point I do remember seeing my intake cam on Bank 1 having to be rotated CCW in order for the block to be set in place properly but I heard that was normal? Someone please correct me if I'm wrong. From there...
Remove chain tensioner, remove upper timing covers on both sides and try to install trigger wheel timing tools. Zip tie the chain in place as well to hold the guide tight since I'll need to do it anyways upon removal of the tools.
If the trigger wheels are off, which it seems most people replying are confident that is my issue, I will loosen the nuts and realign them to fit.
Tighten the 24mm nut on the trigger wheels and then remove the tools and spin the crank 2-3 times to verify timing is good still. I will verify by reinstalling blocks and trigger wheel tools to make sure EVERYTHING lines up. If so, reinstall everything and pray to God.

That is my process due to what I've read from you guys. I hate the fact that I'll probably have to remove the bank 1 upper timing cover because of my new code as that mandates that the chain tensioner comes off but I guess it is what it is.

Thanks again.

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Did you put the alignment sockets on the cams when doing the above? The cams need to be fully aligned with the sockets - you can completely ignore the lock-bolt in the flywheel. Once the cams are aligned, execute same procedure as above again.

Error code / procedure above tells me you did not align cams but only crankshaft - which will never work out

Correct. That is what I did. Now I know.

[Matt.tez]

Before you start the tear down for re-timing, could you hook up INPA, start your engine and monitor the Vanos angles LIVE (click on Engine status, then F6) . You will see how many degrees the Vanos angles are advanced (negative values) or retarded (positive values) on each Bank.
Then you can adjust your trigger wheel’s accordingly and precisely: CCW if advanced, or CW if retarded.

I am having a similar problem but only on Bank-2 with code 34 (hex P22) We can compare notes how that works, short of retiming the whole damn shebang….

Before I took the engine apart for the 4th time since December I did get Vanos and code readings. Here they are below. Nothing seemed out of the ordinary but I am inexperienced in a way. IMG_7649.jpgIMG_7651.jpgIMG_7650.jpgIMG_7648.jpg

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Did not get a new reading for after I went in this past time.

[JimLev]

When you set the #1 cylinder to TDC on the COMPRESSION stroke (very important) the mark on the harmonic balancer will align with the OT mark on the lower timing cover. You will also see the bank 1 cylinder 1 cam lobes tipped toward each other, see pic. Then you know you're on the compression stroke and not the exhaust stroke. Pin the crank. Put the cam lock blocks on, yes you will need to use your 27mm wrench to turn the bank 1 intake can a little to get the lock blocks on. Bank 2 lock blocks will slide on without having to turn the cams.

The lobes will be adjacent to the nuts I’m pointing to.
7A08DD0C-DF31-4DF3-A017-F100144B5554.jpeg