C110+ diagnostic - VANOS live data

[tomrdy]

I've gathered all the ingredients needed for the VANOS service and decided to have a look at what the pre-service values are during a drive.

The live values for the adaption angles (both inlet and exhaust) never budged at all - I assume this means the VANOS is non-operational. Thoughts?

The only change was the position measurement (again, both inlet and exhaust) which stayed at 34-35% for both until I off throttled and it would jump to 0%, then immediately back to the 30's again.

Would be cool if someone has the C110 tool and we can compare values with a serviced VANOS! If we can confirm the way mine is behaving means it's pooped, could be a pretty cheap way to do a basic diagnostic and make the effort of opening up the unit feel a lot better!

 

[tomrdy]

Updated on this.

I completed the VANOS seal procedure yesterday and had a chance to run the tool this morning to see any differences.

I wasn't going to yet originally as I wanted to see how the car felt before being biased but after a good 20 minute drive I'm very sure the car is running differently so just had to check the numbers.

NB: It's said that the seals need some driving to settle. I will check this all again after each tank and update if anything notable changes

I also want to point out that this is a layman's attempt at understanding the VANOS system. My hope is that we can determine what "normal" looks like on a simple-to-use and cheap c110+ tool that anyone can grab to check their VANOS.

Opening up my VANOS, they definitely needed the seals changed (as most expect). Very loose fit to the cylinder walls to the point where the cylinders would probably fall out if held vertically!

My observations before checking data:

- The motor definitely revs smoother.

- I haven't given it a full whack so wouldn't be able to comment on power but there does seem to be better torque and response on take-off from low rpm.


So running the diagnostics with the C110+, here were my observations (i have not run the motor over 4500 rpm):

- The adaption angles still do not change. They have however varied from the last time I checked by .X degrees on each.

- Inlet and Exhaust position %s seem to change depending on RPM but also THROTTLE input. ie: Slow rev vs quick hard jab

- At rest (motor off), positions both return to 12%

- On idle, Inlet 37%, Exhaust 12% (previously stuck at 34%)

- On slow rev, Inlet stays around the same. Exhaust however, changes from 12% > 37%

- Under normal cruising and moderate driving, both values stay around 37% with Exhaust varying to 12% occasionally based on revs.

- On hard jab/rev, I have not worked out the pattern yet. I have seen the numbers jump between 99% and 0% for both but I'm not sure what combo of input (throttle strength / rpm) is causing it.

The only change was the position measurement (again, both inlet and exhaust) which stayed at 34-35% for both until I off throttled and it would jump to 0%, then immediately back to the 30's again.

This has certainly changed. There's no more sudden jumping on/off throttle while driving (except what I observed out of gear and jabbing the throttle).

I am sure that there are quite a few variables and rules that determine what gets varied and INPA would probably give a clearer picture of the operation. I am interested to know whether the inlet % should vary more often. If my understanding is correct, there's at least 2 "modes" for the cams - low and normal rpm. It seems low rpm for the Exhaust cam is 12% and normal is 37%. My inlet cam however, doesn't appear to go into a low mode. Hmm...

Will update this thread with any new findings over the next run-in period... and if i work out something else on the system is broke

 

[mjennings23]

I don't imagine youll notice much power up top, the vanos unit seems more designed to allow more torque at low rpm, at least thats the real difference I noticed when I did mine... much better low range pulling but not much difference up top.

From what I understand it's mainly due to the cams defaulting to 'high rpm' mode when there isn't any oil pressure or something? May be wrong there, but that's my understanding

 

[tomrdy]

I don't imagine youll notice much power up top, the vanos unit seems more designed to allow more torque at low rpm, at least thats the real difference I noticed when I did mine... much better low range pulling but not much difference up top.

From what I understand it's mainly due to the cams defaulting to 'high rpm' mode when there isn't any oil pressure or something? May be wrong there, but that's my understanding

I've read that too actually and nearly everyone comments on the improved response/torque down low mostly which I have also observed myself now.

Another thing i'm hoping to get a reading on is fuel economy.The lowest I got mine to previously was 9.9/100km (~23 mpg?) on highway cruising while giving a full eco-effort which seems kinda bad.

 

[Capa]

Bit off topic - but is there a guide on how to do this, and does it apply to the N52 motor?

Wouldn't mind tidying mine up.

 

[mjennings23]

Bit off topic - but is there a guide on how to do this, and does it apply to the N52 motor?

Wouldn't mind tidying mine up.

M54 only. The N52 has electronic solenoid controlled vanos rather than oil pressure controlled on the M54 (hence why they fail, as the oil seals wear out over time)

 

[tomrdy]

Update to this after some new observations.

- On a cold start, both Inlet and Exhaust sit at 35-38%, even at idle. I think this is related to heating up the cats
- Once motor is up to temp, Exhaust moves to 12% at idle
- Any revs off-idle, Exhaust will match Inlet position between 35-38%. This is different to what I previously thought - that the exhaust would move to 12% at LOW rpm. From my new observation, it literally is just dead on idle that it will be 12%
- WOT (foot to the floor) to OFF throttle will drop Inlet to 0%, then immediately back to 35-38% range. Exhaust does not change away from 35-38%
- Fuel economy around town is 10L/100km. I think this is an improvement over the 10+ I was getting with regular driving. Yet to hit the freeway though.

So far, the only observable difference (using the c110+) after the seal replacement I can confirm is:

- Exhaust returning to 12% at idle. Previously this was stuck at the running range 3X%s
- 0% jump now only on Inlet, and also on WOT to OFF only as opposed to before where any on-load to OFF would see the 0% jump. I am thinking this might have something to do with oil pressure drop off/return as you off throttle?

Human-observations:

- The car is idling on cold start very steadily (this was really my only real conclusive "symptom" as I could literally observe the rev counter shudder on some starts before).
- I still FEEL it has a smoother run up the RPM range. But admittedly after the damn-vanos-job-off-the-list hype, I'm not sure if this is just placebo anymore.

___

I am thinking that though my seals were loose, they weren't completely shot and the unit was still able to hold normal operating numbers (which I am going to assume is 3X% for both cams). The only real issue that was affected by the loose seals was the idling not be able to adjust the exhaust.

Without anyone else running the same diagnostic tool, I guess it's really hard to confirm/reject what is "correct" operation at this point.

Also still odd that the adaptation angle values don't change. I'd have thought they should. [edit]Apparently these can be "cleared"? So perhaps these aren't referring to the variation created by the unit's operation[/edit]

Might need to invest in a INPA set up to read this in more detail as my curiosity is driving me nuts

 

[GuidoK]

With inpa you wont get a % reading; inpa reads out the actual rotation degrees compared to the crankshaft.

You get something like this:
https://www.youtube.com/watch?v=acuvS2eHh6I

(these are measurements on my car with repeatedly wot)

 

[ph001]

You might find these INPA values useful, although they are N52 so might not translate directly....

https://z4-forum.com/forum/viewtopic.php?f=3&t=110050&hilit=inpa

 

[tomrdy]

With inpa you wont get a % reading; inpa reads out the actual rotation degrees compared to the crankshaft.

You get something like this:
https://www.youtube.com/watch?v=acuvS2eHh6I

(these are measurements on my car with repeatedly wot)

Thanks for sharing that - I think for sure getting actual readings like that is probably the next step for me.

If I'm understanding the INPA readings correctly, the output should match the "nominal" value under it (or be close to it) if the unit is working correctly?

 

[GuidoK]

If I'm understanding the INPA readings correctly, the output should match the "nominal" value under it (or be close to it) if the unit is working correctly?

Yes I think so.

Regarding a non correctly functioning vanos: the vanos is controlled by the oil pressure from the oil pump via oil relays. I think the 'rattle' (tell tale sign of a worn vanos) is the relays constanly opening and closing because the vanos cylinders cant maintain pressure (because of leakage past the rings), thus oil/pressure has to be added constantly (in pulses) to keep the vanos cylinder in place.
I doubt that the rings can be so much worn that there is more leakage past the rings than that the oil pump can supply. Maybe it takes longer for the vanos piston to reach its desired position when the rings are worn and oil is seeping past it.

In the vanos screen the top bar (reference NW inlet/outlet) is probably a check for whether the helix gears are mounted in the correct position on the camshafts. This is not of concern to you as you havent swapped camshafts and had to transfer the helix gears. (those helix gears have no marks or notches on what position they should be mounted)