Rough Idle after VANOS repair, E46 M3

[mr_metropolitan]

I repaired my VANOS with new seals, oil pump disk, solenoid, and rattle repair. While I was in there I performed a valve adjustment and replaced the coils/plugs.

Now that I have the car back together I’m experiencing a rough idle. The engine idles at ~900 and stutters as if it were to stall. I have rev’d it up to 2500 rpm or so and it runs fine, but on the come down the revs drop and the engine stalls.

A service engine light came on as well we I powered it on for the first time. I’m guessing it may be timing related, but wanted to get more info before I take the car apart again.

Is there anything code-clearing wise I need to do after a repair like this? Has anybody experienced this issue after a similar repair?

[heinzboehmer]

Did you forget to plug in the solenoid?

Otherwise read codes and go from there

[sapote]

1.I’m guessing it may be timing related, but wanted to get more info before I take the car apart again.
2. and rattle repair

1. The timing wasn't changed if you didn't loosen the splined hubs bolts when working on the vanos module.
2. Did you find the bearings with plays? Lapping the spacer ring is a tricky business -- too much and ended up with a tight or seized bearing and it leads to spinning piston and wear down the piston seals in no time. I suggest don't do this unless you have plays on the bearing shaft axially.

[eacmen]

Did you forget to plug in the solenoid?

Otherwise read codes and go from there

+1 read codes

also clear adaptations (including VANOS)


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[mr_metropolitan]

Thanks for the suggestions y’all. I read codes using INPA and I think it’s confirming the timing issue. I don’t speak German, but my google translating indicated there is too much exhaust gas in the cylinders? Any thoughts?

185 AVANOS1-Regelung
205 Aussetzer Zyl.1 Abgas
206 Aussetzer Zyl.2 Abgas
207 Aussetzer Zyl.3 Abgas
208 Aussetzer Zyl.4 Abgas
209 Aussetzer Zyl.5 Abgas
210 Aussetzer Zyl.6 Abgas
213 Aussetzer mehr Zylinder Abgas

@sapote,

I replaced the sprocket bolts since they were backing out on my engine. In terms of the rattle, I had axial play on the exhaust cylinder and performed the repair on that splined shaft. I followed the Beisan procedure. The intake one seemed ok, but I ended up performing the repair as well. They both spun freely, but the intake side had a bit more resistance when compared to the exhaust.

[heinzboehmer]

Those codes mean that the DME is not able to adjust the exhaust cam to where it wants it to be. Sounds electrical/solenoid related to me, but that's just a guess. Would start will electrical stuff though, since that only takes minutes to check.

First thing I would check is that the solenoid is fully plugged in and the wiring harness for it is good. After that, I'd measure resistance of all the solenoids to see if any are bad, this thread has some good info for that: https://nam3forum.com/forums/forum/m...os-error-codes

If all the electrical stuff checks out, then it might be a mechanical issue. Incorrect timing, hub bolts overtorqued (although unlikely since those things will break before imparting any significant clamping force), etc.

[eacmen]

Thanks for the suggestions y’all. I read codes using INPA and I think it’s confirming the timing issue. I don’t speak German, but my google translating indicated there is too much exhaust gas in the cylinders? Any thoughts?

185 AVANOS1-Regelung
205 Aussetzer Zyl.1 Abgas
206 Aussetzer Zyl.2 Abgas
207 Aussetzer Zyl.3 Abgas
208 Aussetzer Zyl.4 Abgas
209 Aussetzer Zyl.5 Abgas
210 Aussetzer Zyl.6 Abgas
213 Aussetzer mehr Zylinder Abgas

@sapote,

I replaced the sprocket bolts since they were backing out on my engine. In terms of the rattle, I had axial play on the exhaust cylinder and performed the repair on that splined shaft. I followed the Beisan procedure. The intake one seemed ok, but I ended up performing the repair as well. They both spun freely, but the intake side had a bit more resistance when compared to the exhaust.

The 20x codes are misfires.

The 185 code is likely saying the exhaust timing is off. Pull the valve cover and check timing.


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[sapote]

I replaced the sprocket bolts since they were backing out on my engine. In terms of the rattle, I had axial play on the exhaust cylinder and performed the repair on that splined shaft. I followed the Beisan procedure. The intake one seemed ok, but I ended up performing the repair as well. They both spun freely, but the intake side had a bit more resistance when compared to the exhaust.

You meant the cam sleeve bolts and not the sprocket bolts, as the sprocket is held by the same vanos hub bolts which normally don't back out. Are you sure the vanos timing was set correctly?

The cam rotates at 4000 rpm at redline, so any resistance on the bearing rotation could cause the vanos piston to rotate which causes fast wear on the piston seals. You might have lapped the spacer ring a little too far.

[mr_metropolitan]

Thanks for all the help everybody. Sorry for the delay, I was on vacation last week. I wanted to close out this one out.

TLDR - my timing was off.

I measured the resistance across each of the pins on the solenoid based on the link heinzboehmer sent out and I got ~6.7/6.8 Ohms on each one, which seemed ok. Next, I repeated the process of cleaning the valve to make sure there was no issue there. I put it back together, reset adapts, and cleared codes, but still had the rough idle. I then pulled the valve cover and checked out timing. Exhaust cam was slightly off so I re-timed and double checked it with the Schwaben timing tool. Put it back together, reset the adapts, and cleared codes and it runs well. No misfire VANOS codes after the first 20 miles.

[Arehman]

Was gonna say I had the same issue. Ended up being the timing.

[Lee_Enfield]

Glad it worked out. Nothing is worse then putting everything back together and having issues that were not there before. Had a similar experience when I did mine. Put it back together and had a loud intermittent tapping noise. Turns out one of the pistons was sticking in the new pump disk. Had to take it apart again and lightly polish out the bore of the effected piston.

[sapote]

Glad it worked out. Nothing is worse then putting everything back together and having issues that were not there before. Had a similar experience when I did mine. Put it back together and had a loud intermittent tapping noise. Turns out one of the pistons was sticking in the new pump disk. Had to take it apart again and lightly polish out the bore of the effected piston.

Was it caused by using the new pump disk with old stock pistons?

[Lee_Enfield]

Was it caused by using the new pump disk with old stock pistons?

Ya it was. Although it there was probably just a burr in the bore since it didn't take much polishing to fix.

[sapote]

Ya it was. Although it there was probably just a burr in the bore since it didn't take much polishing to fix.

"Put it back together and had a loud intermittent tapping noise."
The loud tapping noise must be by the sticky piston launching outward fast and hit the big roller bearing inner race. These pistons should always be riding on the inner race under the spring load and oil pressure, so the sticky piston didn't move bc it was sticking in the disk too tight until the very high pumped oil pressure knocked it loose and hit the inner race hard.