[Datsun770]

Hello all

I ended up buying the 335i I posted previously about. Went and seen the car 3 times. Drove it, scanned with ista , no issues other than a brake sensor and tilt sensor warning . Nothing major of concern.

Car is a 2007 auto with 109k, decent service history although it could be better. A few receipts confirming some work done including recent cam shaft work, new alternator amongst a few other things. Turbos replaced in 2012 (long time ago now) and car drives great. No leaks or stains underneath after parking up etc and all appeared worth a putt and still does to be honest.

The car has been mapped. No idea what it's running and no proof. The exhaust seems to be after market just due to he tone but no reap idea of what's been changed if anything on the system.

On collection the car wouldn't start but it had sat for a week and had been at the dealer for a couple months under prep for the above recent work. It threw all sorts of warning light up when it was jumped. A scan of the car threw up all sorts of voltage and battery warnings. I asked them to replace battery and I could come back. No nother issues noted.

Collected car and scanned it, a load of errors stored relating to battery so I reset them and away I went a hard drive. I'm now around 200 miles in over a few days.

I've now encountered some gremlins as below.

1. A beeping sound coming from engine bay drivers side, possibly a leaky vacuum hose. This happens only under boost and goes away once off boost. No power lost and no lights. Figured maybe a hose was leaking and the beep is actually a super high pitched whistle, but it sounds electronic which is quite strange.

2. The car is honestly super smooth but when I park or neutral the car becomes Lumpy but without the lost of rpm at idle. It sits happily but you can feel a noticeable lumpyness as you sit at lights when stopped. Now this might be the exhaust and the map causing this as it goes away while driving even at low speed. This Is coupled with a very feint clunk, like a component clunking off another around or underneath the air filter housing. Again this only happens at idle when the car is sitting still and cannot be heard while driving. I found a great post on here with the exact same clunking sound and a load of people seem to have experienced it. Doesn't seem to be anything sinister but more annoying than anything but would be good to know for sure. One for investigation I guess.

3. The oil and coolant is not coming up to temp. Both sit at around 80 so the temp I creases marginally but not enough. This wasn't happening the day before the battery issue so winder if this could be connected? I wouldnt think so and maybe just bad luck the thermostat was waiting to go. The blowers are nit getting warm wither which suggests to me its most likely the stat that's gone.

4. Finally I have a tail light out but the car doesn't recognise that. I'm getting no warning lights the car has had the break light clusters changed under warrant 3 times believe it or not buy BMW so wonder if this is something to do with it. Anyone experienced similar?

I'm sure I've missed helpful info but I will post back here as I get to the bottom of these for anyone experiencing similar.

Still super happy with car on the hole. Joy to drive.

Any advice welcome.

Thanks

[Datsun770]

Edit

When the "lumpyness starts" this isn't straight away on start up. It starts and idles around 1-1.2k rpm then when the valvetronic kicks in after 30 or so seconds the idle drops to 600rpm or there abouts and at this rpm I'm experiencing thus Lumpy stutters feeling and the noise kicks in. Light touch of gas and lifting rpm to around 1k and it goes away.

[whyzee125]

Originally Posted by Datsun770

Edit

When the "lumpyness starts" this isn't straight away on start up. It starts and idles around 1-1.2k rpm then when the valvetronic kicks in after 30 or so seconds the idle drops to 600rpm or there abouts and at this rpm I'm experiencing thus Lumpy stutters feeling and the noise kicks in. Light touch of gas and lifting rpm to around 1k and it goes away.

N54's actually don't have valvetronic. If you're running an unknown tune, I would definitely get that flashed to stock first thing as you don't know what sort of fuel is required and it will be hard to track down issues if you're running a potentially bad tune.

[Datsun770]

That was top of my list. Booked in Friday. I hope they can flash it without any issues with not knowing what it's running at present.

[Datsun770]

I've just been running 99 Ron as that's as good as I can get my hands on and figured that's a safer bet than anything else available. Feels like a stage 1 to me if anything.

[micdev42]

Originally Posted by Datsun770

4. Finally I have a tail light out but the car doesn't recognise that. I'm getting no warning lights the car has had the break light clusters changed under warrant 3 times believe it or not buy BMW so wonder if this is something to do with it. Anyone experienced similar?

I have a 2007 325i pre-LCI (N53B30A). The LED strips in both driver-side rear light clusters failed at approx. the same time. I was unaware as there were no warning lights on the dash. Maybe it's just failed bulbs that trigger the warning lights?

[Datsun770]

Interesting. I'll have to remove a bulb and do some testing, but thanks for that! Something to look at!

[Saif2018]

Originally Posted by Datsun770

That was top of my list. Booked in Friday. I hope they can flash it without any issues with not knowing what it's running at present.

Buy MHD flasher and flash MHD with stage 0, and log the car using Datalogging function and read codes.

When all is well, flash stage 1 map.

Check this link... https://www.e90post.com/forums/forumdisplay.php?f=58

There's quite a few knowledgeable goys who may be able to point you in the right direction.

Check this site out for guide/tips on modifications and diagnostics...

https://bmwtuning.co/category/n54/

[Wolf 335]

Originally Posted by Datsun770

Interesting. I'll have to remove a bulb and do some testing, but thanks for that! Something to look at!

As micdev42 mentioned, on E92's the rear running lights are powered by 3 led strips. Each strip is powered by its own led, so 3 led's per tail light.

Early models had an issue with one, two or three led strips turing off, being dimmer than the rest, and/or flickering.

Problem is the soldering connection of the led.

When these led's fail, they do not trigger a code.

Led circuit board is enclosed inside the tail light and is not a servicable item.

Guys on the forum here have cut open the tail light housing to access the led circuit board and re-solder the connection points and some have replaced the led bulbs.

- Replacing led's does not give the same light output as the original, so there will be difference.
- Don't buy used tail lights from earlier models as they all have this problem.

There is quite a detailed thread on here regarding this issue and where exactly you need to make the cuts in order to access the circut board.

- I even placed the tail light in the x-ray machine and scanned it to show exactly where these connections are.

Have a look at this: https://www.e90post.com/forums/showthread.php?t=1441049

In addition to the above, it may be worth inspecting the trunk wiring loom. You will have to pull the rubber covering and push it into the hole below the rear window. This will give you clear access to all the wires. I bet you will find some wires if not broken then on the verge of breaking.

[micdev42]

Originally Posted by Wolf 335

As micdev42 mentioned, on E92's the rear running lights are powered by 3 led strips. Each strip is powered by its own led, so 3 led's per tail light.

Early models had an issue with one, two or three led strips turing off, being dimmer than the rest, and/or flickering.

Problem is the soldering connection of the led.

When these led's fail, they do not trigger a code.

Led circuit board is enclosed inside the tail light and is not a servicable item.

Guys on the forum here have cut open the tail light housing to access the led circuit board and re-solder the connection points and some have replaced the led bulbs.
...

Hi. I read all that stuff about cutting open the lights, resoldering LEDs etc. I tried it on the outer lamp cluster and failed miserably! This was an MOT failure and at the time - about a year ago - the only unit I could get was from BMW. About £200 yikes. So I bit the bullet and replaced it. Then after reassembly the boot mounted light cluster LEDs failed as well. Another £150 from BMW! still they should now last forever... Cheers