Monitors INC

[MX7]

2005 Z4 3.0i with 37,000 miles

Car due for its New York US inspection. Car did not pass as the there two monitors incomplete (car will pass with one incomplete, but not two). Mechanic charged me the inspection fee and gave me a 10-day temp inspection. Told me to drive it and bring it back.

That was about 3 weeks ago. I’ve put 85 miles on the car, mostly short trips but also one that was 10 miles each way. Checked again and both monitors are still inc.

They are: CAT and O2.

I broke out my better Creator2 OBD scanner and found:
- oxygen sensor control bank 1: not active
- oxygen sensor control bank 2: not active

The code reader shows values for all other indicators, which are:
- signal, Ox sensor bank 1 before CAT
- signal, Ox sensor bank 2 before CAT
- signal Ox sensor bank 1 after CAT
- signal Ox sensor bank 2 after CAT
- adaptation, mixture, bank 1 additive
- adaptation, mixture, bank 2 additive
- adaptation…. Multiplicative (both bank 1 & 2)

I’m not sure where to look for further info on the CAT monitor being INC.

After 85 miles I’m surprised the monitors have not set. I know there’s a drive cycle (which I’ve done before, but I’m not convinced it caused the monitors to set more quickly). Do I simply need to drive it more (if yes, how much more???) or does this indicate there’s some other issue that needs to be addressed?

While reviewing the live data stream (after starting the car) I see “True Running Value” for each cylinder to be zero except cylinders 2 and 5 which have varying values around 0.3-0.6 1/S2. Anything to be concerned about that not all are zero?

[mmm-five]

Did you replace any of the broken sensors? If not, they're obviously still broken!

[MX7]

Which sensors are obviously broken? Are there two O2 sensors before the CAT? And they both failed at the same time?

I’m going to try the drive cycle today to see if that helps.

[mmm-five]

Which sensors are obviously broken? Are there two O2 sensors before the CAT? And they both failed at the same time?

I’m going to try the drive cycle today to see if that helps.

The messages are saying they're not receiving any info from either of the O2 sensors, so sounds like both are broken/failed (in my case it was a damaged cable coming out of the rear-most one).

You can't repair them, they have to be replaced (or at least that's the first step in trying to rectify the issue).

[MX7]

Note that there are values showing for both Bank 1 and Bank 2 for the “signal oxygen sensor” bank 1 & 2 “before CAT”. Both values are 0.4. If neither sensor is working, why would there be values showing for this parameter?

[enuff_zed]

Seems odd to have exactly the same codes on both banks. In my experience (on the M54 engine) this more often points to an air leak on the intake side of the engine.
Check the intake pipes and in particular the elbow at the throttle body. The smaller corrugated pipe on top of it is prone to splitting.

[MX7]

Thanks for the input. I’ll poke around tomorrow (weather permitting) and see what I find.

I just completed the drive cycle. Both monitors are still INC. Went though looking for codes and did find two:
- 2882 DME mixture preparation Bank 1
- 2883 DME mixture preparation Bank 2

Does this further indicate its running lean (and therefore point to an air intake issue)?

[Mike6]

Yes this would normally point to a leak on the air intake arrangement. But, I am getting those codes having had both post cat sensors replaced due to failure of the heating element in one sensor. When the weather warms up I will be looking at possibility of sensors not seated correctly as old ones had to be burnt out or failure of exhaust connection where it bolts onto header. Hopefully yours is just a split in the rubber boot.

[enuff_zed]

Thanks for the input. I’ll poke around tomorrow (weather permitting) and see what I find.

I just completed the drive cycle. Both monitors are still INC. Went though looking for codes and did find two:
- 2882 DME mixture preparation Bank 1
- 2883 DME mixture preparation Bank 2

Does this further indicate its running lean (and therefore point to an air intake issue)?

Yes those are the common codes for an air leak.

[MX7]

As usual, you’re 100% correct.

Pulled off the air intake and found what I’m looking for. Unfortunately it’s not the most accessible piece to remove. Unless someone has a link or instructions on how best to access the hose clamps, I’m going to research the part number and order the part. Once it arrives I’ll take another run at it. If I get to the point where I’m concerned about getting in too deep I’ll have to have my mechanic replace the part.

IMG_8771.jpeg (176.8 KiB) Viewed 342 times

[MX7]

Appreciate the help confirming… the p/n I need is #5 in this diagram (13547514867), correct?

IMG_8772.png (210.87 KiB) Viewed 337 times

[MX7]

Part ordered ($50) but won’t arrive for a week…

[MX7]

Found this video for a 3-series. It provides enough info where I should be able to tackle this when the part arrives.

https://m.youtube.com/watch?v=zNeKMpS1oEk

If there are any comments or suggestions to make it easier, I’m all ears!

[enuff_zed]

Yup. Glad it was an easy one.
If you remove the disa valve too then you’ll have plenty of room to do the pipe. Make sure the pipes are on square before you tighten the clips.
You can also check the disa while it’s off to make sure the flap isn’t loose on its pins

[MX7]

It was the disa valve that I didn’t want to mess with, but after watching the video it looks like an electrical connection and a couple of bolts.

If the flap is loose (what is a disa valve anyway?) is it something I can tighten or will I need to replace it? If it needs replacement I’d like to get everything I need before I get back in there.