Timpnw P0021

[timpnw]

@jimlev - I've read every post of yours on this subject and I'm still unsure on next steps. I've just finished up my at home M62TU '03 540 rework with the GAS tools. Now it's running great with rebuilt vanos... lots of high fives to myself, but now I have been hitting the revs, I'm getting a P0021. I clear the codes start it back up. All good for a few mins of idle and revs, then the code hits again.

I took the DS valve cover off, set the engine to TDC. I remove the examining hex bolt in the UTC and my bit goes right go through the hole in the wheel. I set the DS intake camblock on and have to wiggle them on a degree or so CCW. That move prompts me to move the wheel a degree or two as well with the open end wrench CCW. Bit goes through the hole as a final check.

I button it back up, runs a little longer at idle with revs and then the code kicks again. P0021.

Is it a red flag the driver side intake camblock needing a tiny bit of finagling to slide the cam block on?

What should my next steps be? Try to move the timing wheel again maybe per your instructions above? Should I remove water pump and UTC and retime the drivers bank? Rip down both sides and retime both? Thanks in advance for reading my post.

I'm wanting to avoid the inevitable of pulling that water pump back off and redoing this... but it is what it is. Thanks in advance.

[JimLev]

Tim, some questions.
Were you 100% sure the vanos was fully retarded before to started to tighten the center cam bolt?
If the trigger wheel is more than +/- 10 degrees off code P0011 (bank 1) or P0021 (bank 2) is set, DME testing ends and the vanos solenoids are disabled.

Did you have any slack in the chain on the drivers side? It needs to be tight.
Pass side shouldn't be loose either.

Are you sure a tab on the trigger wheel didn't get slightly bent?

Did you get the upper timing covers pressed down good?

After you finished did you manually rotate the engine 3 revolutions, put the cam blocks back on and check the trigger wheels?

P0021 is the cam is over advanced which would indicate either the center of the Vanos wasn't fully retarded, the trigger wheel is not set right.
Typically the cams are set correct to the crank, the static timing, so it's something to do with the vanos or trigger wheel providing the chain wasn't loose.

Its got nothing to do the cam position sensors or the vanos solenoids, they have their own codes.
You could have 2-3 things slightly off (stacking tolerance errors) which will cause the code.

[timpnw]

@jimlev - Thanks for the detailed reply. From your comments, I understand the code more. Man, I love turning a wrench, but this has been a pretty challenging project for me, as I researched it from the ground up. After tearing down my car, I really realized what kind of mediocre job my indie mechanic had done in the past. Learning lots on this, just not enough time in my life to get it done quickly...

OK - comments/response below:

Alright, +/-10degrees seems like a lot more variance than I thought was there. I was thinking it was more like +/-2degrees.

1. I'm pretty sure the vanos was fully retarded when i locked it down. I received them back from Vanosman in the fully retarded position. then I worked them back and forth to make sure they were set.

2. Slack in the chain with the UTC on (not while the lower Timing cover was off as I had a zip tie) is possible but not probable enough to jump a tooth on the crank. Plus, my gut tells me a jump crank tooth would put both banks out of sync.

3. Trigger wheel looks good. No issues.

4. I used the GAC method and the Beysian method to press both UTCs down. Both driver and passenger are the same. Those new gaskets are a little thick but it's pretty close to flush. It's not flush but both are very very close within a mm. Reading through the forums I didn't think this was an issue. (I cranked down the Valve cover gasket on so tight on on of them I ended up stripping out one of the cam caps... so upset this isn't a easily sourcible eBay item)

5. OK - I do recall that after manually rotated the engine and had to reset the wheels. They were off by a little a couple degrees.I put the blocks back on and I reset the wheels at that time. Now as I type, that might be my red flag that I had to reset those wheels meaning that those vanos gears were off when I snugged up, but they didn't move and I think i recall using the GAS vanos tool to initial rotate them down. Everything turns CCW anyway, so I didn't think that it would even be possible for them to come loose. Retard vanos CCW , intake bolts CCW etc.

I'll go back to my original question... after going TDC having to wiggle the intake cam to get the block on bank 2... Would that be an issue? If it's just bank 2, can I simply 'retime' bank 2?

[JimLev]

With the flywheel locked, crank set to TDC my Koch cam blocks drop right on bank 2. I don't need the wiggle anything.
I've never used the GAS tools or tried to time just one bank. As long as the crank and all the cams are locked you should be able to do just bank 2.
P0021 is over advanced so either the vanos, the trigger wheel, or both need to be turned CCW.

[timpnw]

Makes more sense.

Here is the scenario I'm now wondering about. I properly set the timing with the vanos wheels and I remove the cam blocks and the crank pin, and hand crank it 3 times. After that, I set the blocks back on. I notice the wheels are off by a tad and need to be set again. Does that (the wheels not being exactly where they were 3 revolutions ago) mean the vanos gears were not fully retarded?

[JimLev]

Does that (the wheels not being exactly where they were 3 revolutions ago) mean the vanos gears were not fully retarded?

It could be either, no way for me to tell from my kitchen counter. You could just reset the wheels and see if it's fixed or lock everything and start over. That may be the quickest thing to do.

[timpnw]

Got it. I guess... when turning it over 3 times before buttoning it up, I was curious what I should expect. If the wheels are always misaligned after aligning htem then something is probably weird with the vanos gears. Sounds like this might be my area of opportunity. I'll open her back up and report back. Thanks!

[JimLev]

After you spin the engine over by hand you have the pin the crank and put the cam lock back on. Only then you can verify the trigger wheels are correct.