Guidance Please 🙏

[ShortStack]

Hi all,

Seeking some guidance if i may;

Purchased an 08 plate 2L sport E85 in early October '23 from a trader in Kidderminster. Had 84k on the clock.

Got it about half way back to Bath and the emissions warning light came on. Didn't really think too much of it assuming sensor, easy enough to remedy. Couple of days later the coolant light came on and steam coming from under the bonnet on start up, heating also stopped working. Ticked over fine, still felt fine to run local, coolant levels were fine. Booked it into a bmw specialist garage in Bristol to get it sorted and my dad said no, go back to the dealer its under warranty. Contacted the dealer, he said he wanted to control the work, so bring it back to him in Kidderminster. Fine. We agreed a date. That was mid November, he then delayed taking it back a few times for reasons his end so it didn't end up being dropped up to him till 16th December. Got it back on 15th January, he advised with new thermostat and new radiator cap as the cap reportedly had a crack in it. It wasn't driven back to me in Bath, it was delivered on a truck. Have done less than 30 miles in it and the emissions light is back on. Noticed this evening steam coming from under the bonnet again on start up.

For convenience sake i feel inclined to just get it sorted out myself at my preferred garage.

But I'd like to know, what would you do?

Sincerely,
A young lady out of her depth who doesn't want her dad to say "i told you so" about having brought a Z4 to start with.

[enuff_zed]

I have never heard of the cap cracking, but the expansion tank often does. It's a simple fix tbh.
For the emissions you really need a code reader to find out what the issue is. It could be so many things.
I would not go back to the dealer tbh.
See if a local member can help you read the codes first.

For the coolant leak, see if you can see where it is coming from. Don't have to get all technical, just post up a few photos.

[tug]

If the emission code comes up as P0420 Catalyst Below Threshold Bank 1. Then don't worry, its the most common code on the 2.0 and doesn't affect performance or the engine in any way. Just get a cheap OBD reader and turn the light out. To prevent this light appearing you need to give the motor more of a thrashing, as in, take it up to at least 4000rpm through the gears when warm and wherever possible.

I have had this intermittent problem for 10 years, Although mine is a N46 Phase 1 and yours is a Phase 2 N46 the same applies.

Hope this helps and puts your mind at rest so you can enjoy the zed. And you have made the right choice, there's nothing wrong with the 4 pot

Cheers, tug

[enuff_zed]

ShortStack, there you go. tug is president of the N46 appreciation society and definitely the man to go to.

[paddy wright]

Sad start to zed ownership but you will be sorted soon and have a great wee Z. Welcome along.

[Sidewaze Samm]

You should probably give the dealer a 2nd chance to fix it - on the understanding that if it isn't fully fixed then you will use your legal right to reject the car for a refund. There are other zeds out there.
How did you pay for the car? Credit card or dealer finance would be really handy...

[ShortStack]

Thank you for the guidance chaps.

Took him out this morning for a 4k+ revs run, it was fun and terrifying, I can confirm I have been driving it like a girl before now

Code reader aquired - we'll see what that comes up with. If its bad I'll contact the dealer I purchased from, otherwise I'll just resolve myself locally for convenience. I paid for it in cash/bank transfer and have receipts etc.

Its also a Sapphire black, similar but different to Tug's.

Grateful for your input!

[enuff_zed]

Thank you for the guidance chaps.

Took him out this morning for a 4k+ revs run, it was fun and terrifying, I can confirm I have been driving it like a girl before now

Code reader aquired - we'll see what that comes up with. If its bad I'll contact the dealer I purchased from, otherwise I'll just resolve myself locally for convenience. I paid for it in cash/bank transfer and have receipts etc.

Its also a Sapphire black, similar but different to Tug's.

Grateful for your input!

Clear all the codes you find as there may be old ones still stored.
Then run another full scan and see what is left.
Stick photos of the scanner screen on here and I'm sure you'll be inundated with suggestions.

[enuff_zed]

I have been chatting with ShortStack off line and we now have some codes:

4-pot codes.JPG (70.24 KiB) Viewed 172 times

I have asked her to clear these and see what comes back.

My thoughts are that is a fault with the valvetronic servo motor, or possibly the signal to it from the eccentric cam sensor.
Any other thoughts.
Pretty sure I'ver seen all those codes caused by the valve timing being wrong.

[enuff_zed]

ShortStack, I'll to try to explain what I'm on about:

The servo motor operates to adjust the opening and closing of the valves by moving an eccentric cam as the engine revs change.
If it doesn't do this then the flow of fuel/air mix through the cylinders isn't ignited at the correct time, causing a drop in power. Unburnt fuel then passes through into thre exhaust which can upset the oxygen sensors (hence why you have those codes).
The DME is the engine ECU and it detects this problem and puts on the EML to tell you there is an issue to be sorted out.
The misfires can also be caused by the timing being wrong and the spark not igniting the mixture properly.

To cure this you need to replace the servo motor. BUTY, you could do that and find the problem is still there. in this case the Eccentric Cam Sensor, which measures the angle of the adjustment and tells the servo motor wqhat to do, is probably faulty.
The sensor has an electrical plug which pokes up through the front of the cam cover. The seal around it leaks and oil gets past, drops into the plug and messes it up.
Given that the same dismantling is needed for both jobs I would recommend doing both at the same time.
You will also need to replace the top cover gasket and the seal around the sensor plug.

I wonder if your warranty still covers that? (Or even if they'd believe you?)
If not, then hopefully a member closer than me can help out.

Screenshot 2024-02-11 114249.png (156.85 KiB) Viewed 162 times

Screenshot 2024-02-11 114443.png (142.58 KiB) Viewed 162 times

Screenshot 2024-02-11 114545.png (103.28 KiB) Viewed 162 times

[enuff_zed]

Oh and just realised we never clearerd up the coolant issue?
Is that a still a problem too?

[tug]

Not to question your knowledge or take away anything you brilliantly described and you are probably right. But to me those codes all point to a duff valvetronic. Just my two penneth though mate.

[enuff_zed]

Not to question your knowledge or take away anything you brilliantly described and you are probably right. But to me those codes all point to a duff valvetronic. Just my two penneth though mate.

You're hardly questioning me mate, when you're saying the same thing.
Same thing, different names.

[tug]