Rough idle (with codes)

[Laust]

I am posting to get some ideas and maybe consensus on what the problem could be, since I am not into random parts swapping ... except if that activity is very simple and low cost.

The rough idle started as barely noticeable, but after three or four 60 mile drives (each with cold starts) the problem got worse and eventually the CEL came on at subsequent cold starts. First it was blinking and finally settled in as continuous. The car still has good power once hot and on the freeway and the idle roughness seems less when hot.
The fault codes as measured with a cheapo reader was as follows: P0011, P1341, P1343, P1345, P1347 and P1349. According to Google the codes mean the following:
P0011: engine control module (ECM) has determined that the bank 1 intake camshaft is more advanced than what the ECM has commanded it be
P1341: Multiple cylinder Misfire with Fuel Cut-Off
P1343: Misfire cylinder 1 with fuel cut-off
P1345: Misfire cylinder 2 with fuel cut-off
P1347: Misfire cylinder 3 with fuel cut-off
P1349: Misfire cylinder 4 with fuel cut-off
However after erasing the codes and starting the engine again, the idle is better, but then starts to worsen. It also looks like the P0011 is the first to show up and the rest adds on slowly.

I went through all the accessible electrical connections and installed a new (low cost) cam sensor without any noticeable improvement. I also looked at the sparkplug well and there was no oil. As a sample, sparkplugs #1 and #4 looked good.

I changed the chain guides plus the tensioner about 4k miles ago with no codes (and no external oil) showing and until now the engine has been idling very smoothly.

Another symptom, that may be related, is brief but random 0 to 2 second rattle on start-up. About 10% of the time it doesn't rattle at all, even after sitting for weeks.

What could be the root cause?

At this point my bet is on the right VANOS unit.


Laust

[TheAngryBear]

The sprocket may be working loose or just off time, the solenoid may be failing, or bad position sensor.

I would first try swapping the solenoids and see if the code follows.


2001 750iL DD74441
Stock

RIP: 2003 540iA Sport GS56111
H&R front springs, Ultimate Cup Holder, Euro Dash & Armrest, Grom, BavSound Stage1

[Laust]

Thank you for the advice. I will try the solenoid swap at the end of next week.

[Laust]

So I decided to "seek professional help", starting with diagnostics, by going to the nearest shop willing to take on the task. When arriving there the CEL had just started coming on again (after I had cleared the codes) and they read the BMW code to be "33, VANOS inlet camshaft control Bank 1", which corresponded to the P0011 that I read with a simple OBD2 scanner. They also verified the cam-crank correlation to be off with a scope, but did nothing beyond that. Their "probable cause conclusion" was that the chain must have skipped a tooth, which seems nearly impossible to me, since I noted during the chain guide repair, that the chain was very difficult to put on even with no chain tensioner installed. So that apparently was a wasted $103 for the diagnostic effort .... but maybe not.

On my way home from the shop I discovered to my surprise, that the car was idling smoothly and after 6 or 7 small trips it is still idling smoothly. Furthermore the frequent start-up rattle seems to be gone.

My guess is that there were some crud (maybe pieces of O-ring(s)) in the VANOS unit, that has now been flushed out, or maybe I am the lucky owner of a self-healing car

[kouks]

Before you get too excited and think all is well...

A P0011 code on an M62TU is almost always a chain guide failure if the guides are original. If the guides were recently done, then it may be a solenoid or a camshaft position sensor issue.

Here’s why a P0011 code usually means chain guide failure.

The chain is pulled from the bank 1 VANOS gear through the U chain guide and onto Bank 2 VANOS gear. The plastic guides will fail near Bank 1 and the plastic bits are pulled toward Bank 2 on the guide. Thus the chain gets loose on Bank 1 and remains nearly intact on Bank 2. Being loose, the chain allows the Bank 1 cam to over advance timing, and you get a P0011 code.

I suggest you drop the oil pan and inspect for plastic bits. My sons e39 540i made no chain noises at all and ran fairly smooth, other than a P0011 code. Sure enough, the chain guides were busted.

The VANOS is fairly robust. Even if the seals are completely gone, it will just fail to advance timing and you will get a wobble but not a P0011 code.

A bad VANOS solenoid can cause a rough idle. But not P0011.

[oldroller]

Since the guides were replaced 4k ago my bet would be the trigger wheel has moved slightly due to everything wearing in.
Pull the right valve cover, TDC and pin it, check the trigger through the hole in the upper cover while holding the intake cam in
full retarded position. An appropriately sized drill bit through the hole should find the center of the hole in the trigger wheel.

A number of posts here regarding the fiddly adjustment of the right bank trigger, some adjusting slightly retarded to eliminate the code.

[kouks]

Oops, did not read that he replaced the guides.

The rattle at startup is VANOS seal gone bad. You may want to rebuild both VANOS units. In the TU engine I highly recommend VANOS be rebuilt when chain guides are done since the VANOS seals are well gone by then too. VANOS will normally not cause a P0011 code but since the code at the Indy created a VANOS code, then that’s probably your culprit. Do both.

Unfortunately that hat means taking both valve covers and upper timing covers off and re timing again.

Dont be frustrated. I did my son’s e39 540i guide a couple months ago and the VANOS, then discovered a bad camshaft and now possibly a bad bank 1 VANOS. I’ve had the thing apart and retimed it 4 times already. Will be replacing the cam and VANOS on bank 1 again over the Christmas break.

When you do retime it, snug everything up, do not torque all the way, remove the blocks and pin, hand spin the engine one complete turn, replace the pin and blocks and remeasure. After any adjustments, do it again until there is no more adjustment needed, make sure every time you have both intake cams full retarded, they will move in the VANOS. This is a technique for removing any slack in any part of the chain and that the timing is settled in correctly. The non TU engine is not this finicky, but the TU can be a pita to time correctly with the VANOS.

[oldroller]

+1! Finger.gif

[Laust]

Thanks for the suggestions.

The P0011-P1341- etc. has still not shown up, but oscillating idling and stalling occurred with a resulting P1638 (Throttle Stuck Temporarily) code. Fortunately I managed to cure that, at least for now, by cleaning the throttle body (TB) and internal gearwheels as well as giving them a bit of oil. A few years ago I had a throttle problem show up, when driving on a rough surface. It turned out to be a wire problem in the connector to the TB, which was cured with massaging and electronic spray, so probably oxidation. It may have been the same problem this time as well.

The fact that the rough idling "cured itself", at least for the time being, leads me to believe that the VANOS is the root problem. Fortunately it doesn't seem urgent right now, but in order to prepare for the repair I do have a few questions, namely.

1) Who would you recommend to do the VANOS reconditioning, Vanosman or DrVanos?
2) Where can rent the necessary tools*?

* At the chain guide renewal I did not use a cam timing tool, but marked a sprocket tooth for each sprocket to match the specific chain gap locations, assuming that the cams were timed correctly before disassembly.

[oldroller]

You did a very close job of it considering no timing tools and a discerning eyeball. However, the settings are specifically
precise. Likely your timing wheels/tabs are a bit off. I would not expend the time/energy on the Vanos units until you are certain
the timing is on.

You could get by with a bolt for a flywheel lock pin and a drill bit for the trigger check through the upper timing covers to check the wheels.
Make sure the lettering on the rear cam blocks are up, pin the flywheel, and check the triggers. The right bank intake cam must be held against spring
tension counterclockwise when checking bank 1.

Just might clear up your drivability issues.

[kouks]

Just Google BMW tool rental and a couple places come up. If you did this without tools you’re lucky it still runs and you did not damage the valves. Get the tools and re time it the right way, and I’d do the VANOS using Besian Systems, or if you don’t want to do the rebuild, you can get them ready to go (for a lot more $$$) at Dr VANOS.

[georgebest]

T
1) Who would you recommend to do the VANOS reconditioning, Vanosman or DrVanos?

Tried both, they both did a good job. Vanosman was much cheaper than DrVanos though. As others said, you can actually do it yourself as well, could be a pain if your VANOS unit is slightly off center like mine was.
I would just buy the timing tools and resell it on Ebay when finished the job, this is a good one for $92: https://www.amazon.com/8MILELAKE-Cam...2tu+timing+kit

[Laust]

The rough idling (with P0011, etc.) came back again and I will pursue the VANOS repair. The car has done 206k miles, so big surprise on the need for VANOS repair. Otherwise the car behaves quite well.

Btw, I don't think I was "lucky" with the cam timing when installing the new chain guides about 18 months ago. The method has just one premise, which contains some uncertainty, namely that the chain had not skipped a tooth since the engine was built in 2001, which was supported by its smooth and powerful behavior. As soon as I could get to all 3 sprockets (the crank and the VANOS sprocket for each intake cam) I selected a single tooth on each, marked both the tooth and the mating chain link as well as counted the number of links between each of the 3 points. When putting the chain back on, I made sure each marked link got on correct tooth.
However, I suspect that this indexing method has some serious risks when rebuilding the VANOS units. So therefore my interest in direct cam timing at this point.

[Laust]

Update:
I have taken on the project, bought a $92 tool set as "georgebest" suggested and am getting close to the VANOS units. However the deep 32 mm socket included in the tool set does not fit the VANOS solenoids (ID maybe 0.5 mm less than the OD on the solenoids), so I am now being delayed by at least a week trying to have the socket bored out.
The cam locking blocks work well and I can only hope that the tools for aligning the cam trigger wheels work well to.

Laust

[georgebest]

Update:
I have taken on the project, bought a $92 tool set as "georgebest" suggested and am getting close to the VANOS units. However the deep 32 mm socket included in the tool set does not fit the VANOS solenoids (ID maybe 0.5 mm less than the OD on the solenoids), so I am now being delayed by at least a week trying to have the socket bored out.
The cam locking blocks work well and I can only hope that the tools for aligning the cam trigger wheels work well to.

Laust

Did you buy the tool I linked (8MILELAKE)? That socket worked for me. Tried previously another one from Ebay and run into the same issue as you did.

[Laust]

Did you buy the tool I linked (8MILELAKE)? That socket worked for me. Tried previously another one from Ebay and run into the same issue as you did.

Now you tell me

I went to eBay, where the bottom prices are the same, since I recently moved and have not yet updated my address on Amazon. This was the specific offering I bought from (https://www.ebay.com/itm/For-BMW-M60...53.m2749.l2649) and with 269 units sold, I did not expect problems ... oh well.

Under normal circumstances this would only be a minor problem, since I have a combination lathe mill, but the boring bar and tool holder is nowhere to be found even after spending a frustrating amount of time diving into moving boxes.

[georgebest]

Sorry to hear! It seems all the kits on Ebay has this issue.

[Laust]

I finally finished the project of finding, installing and timing two rebuilt VANOS units (gears) and leaned a few things in the process.

My “bible” on the subject was the “Beisan Systems Procedures – M62TU Vanos Procedure” found here http://www.beisansystems.com/procedu..._procedure.htm , which was very helpful for sequencing the tasks, getting the right tools, purchasing parts and finding relevant fastener torque specifications. However it omitted to mention a few useful O-rings in the parts listing, namely 2 ea of 07119906361 (O-rings for exhaust cam chain tensioners) and 2 ea of 07119901511 (O-rings for emission control air pump tube).

I decided to have the VANOS units rebuilt by Vanosman , who was very easy to work with, even after he found some small cracks on the internal plastic parts on both my units. Prior customers with similar small cracks had requested them rebuilt anyway and apparently with functional success. I was not inclined to take the chance, however small, of having to repeat the effort, so he gave me a good deal on units already in stock.

Fortunately the effort of getting the VANOS gears out and putting the “new” ones back in was relatively uneventful, except for specialty tool related issues. As mentioned the deep 32 mm socket had too small an ID, but I managed to get some time on a lathe to bore it out to a little more than 32 mm, so it fit the solenoids. The tool for timing the trigger wheel on bank 1 could only be based on the two mounting bolts (no upper edge to lean on), so I loosened the mounting bolts slightly, found the max and min angle and fixed the tool (and trigger wheel) in the middle.

While at it, I had also decided to change oil and filter, so the oil was drained early on, meaning that at first start up (with empty VANOS units, empty chain tensioners, half-filled oil canister and empty paths to most hydraulic actuators), I could expect a lot of “unhealthy noise”.
I had also decided to postpone adding coolant and the fan, until I was reasonably certain that the project was a success. In that condition I am estimating that the engine can idle safely for up to one minute.

1^st start-up (about 15 sec)
The “concert of ugly noises” was even worse than expected and was fortunately diminishing with time, but the computer was quick to find problems everywhere and send the engine into “safe mode” and trigger the CEL.

2^nd start-up (about 20 sec)
The engine was getting quieter, but began to oscillate and at the end the temperature gauge raced to maximum. Turning the ignition on after a 10 minute wait showed the temperature gauge still at maximum.

It turned out that I had forgotten to connect the two small hoses to the intake just before the throttle body and had not pushed an oxygen sensor connector all the way in. I disconnected the battery for 10 minutes to get the coolant gauge to “relax” and also thought it was time to mount the fan and add coolant.

3^rd start-up (about 40 sec)
Now the engine was getting quieter than I have ever heard it before, including the noise that had sounded like a knocking connecting rod.

Now I have driven the car maybe 20 miles on a few local trips with no hiccups or codes and feel that the whole project has been successful and worthwhile.

Laust

[georgebest]

Congrats! Good job. Smart following the Beisan guide, probably the best out there.

[Laust]

Congrats! Good job. Smart following the Beisan guide, probably the best out there.

Thank you and also thanks to everybody else contributing here. At the very least it provides motivation to finish the job in a reasonable time frame.