Capa said:
Yeah, I'm about there with you on that. I'm thinking some kind of oil filling syringe and a cigar is where I'm gonna go.
That's interesting to know in regards to CCV. When I take the oil cap off, there's obviously vacuum there, but the car doesn't try to martyr itself. I think changing the PCV is on the list, but given I've got an N52K it'd be a whole new rocker cover, and right now I can't really be arsed. Nor do I want to shell out £2-300 on the part.
I'm still sort of on the fence, considering whether I actually invest the money and try to fix it or go and part-ex it for something else currently. I think the noise on mine has now morphed into some kind of rattle and 'whoosh' noise between 1500-2500 rpm. Research is leading me to suspect the small DISA.
Yet more fun...
Exactly, that seems to circumvent the need for a pump and a standalone smoke container. That sucks with regard to the CCV. The bonus is, although it's expensive, it's certainly a lot easier to change than on the earlier N52! I've seen something like this for your application which might work: https://www.ebay.co.uk/itm/11127552281-BMW-Valve-cover-repair-kit-N51-N52-N52N-N52K-N52T-/172189766625
I suppose it depends on whether the PCV related bits in the valve cover are blocked and such.
Urm, if I was in your position again, I'd probably sell the car, although I'd struggle to find a suitable replacement. Obviously I thought each time I fixed something, it was going to be the fix of all fixes, and I'm still trying to track this s**t down! Rattle and whoosh is certainly odd, I think you're on the right lines with the small DISA :/
juld0zer said:
Propaintballa - I came up with a theory of false traction control intervention (throttle opening restricted and injection reduced) but I would have expected the skid light to be flashing at the same time. A few days later, the theory was proven false when the juddering returned and this time it is the worst it has ever been.
Pulled and inspected all NGK spark plugs which were fitted in January, nothing really stood out. Fitted another 6 donor coils from a known good set. Even replacing the bloody tank vent valve made no change to the juddering or the negative long term fuel trims. So i'm down $200. I also made a ground strap from the rocker cover to the strut tower as the existing one is corroded. No difference.
Compared actual vs setpoint MAF at idle, 1200 and 2000rpm and it was acceptable.
Did the same with VANOS, Valvetronic eccentric shaft position, throttle body and gas pedal, all was acceptable. I didn't scope anything, so there is still a chance of a high frequency jittery signal. This was all done using values in INPA which has a somewhat slow refresh rate.
I did make a discovery that turning on the AC restored acceleration and significantly reduced the judder around 1400-1900rpm. The flat spot is significantly reduced. I can induce the juddering by turning off the AC. On my Scanguage, I am currently monitoring load, throttle position, ignition timing and intake air temp. When the judder occurs, timing is being retarded. When the flatspot peaks, load is 99 and timing is very close to zero (TDC) or negative at the worst (after TDC). Is this a sign of false knock detection?
I have bit the bullet and ordered a DMF and clutch kit......
Interesting findings, and odd that your A/C being on reduced the symptoms, mine stay the same. The most interesting though is your observation of the timing, which fits in part with my thoughts on this. Not that I've experienced a proven example of this, but for me, the judder feels like an engine that is not timed correctly. It feels like I am keeping the pedal at the same position but gradually the car slows down as it's juddering. I also feel like my rough idle would be characteristic of engine knock, as it's not a consistent misfire, but more like a shiver.
The sick thing is, this could still be several things. It could be the absolute nightmare scenario of cam bearing ledge wear affecting oil pressure that in turn means the timing is incorrect for the engine speed. I think this could still be a factor, even if performance in the higher rev range is fine due to higher oil pressure? I don't know :/ Seeing as that's quite rare I feel like logically, based on fuel trims being quite far out, that this is a fuel/air metering issue. So MAF, MAP, Knock, 02 sensors or vacuum leak. I'd lean more towards a sensor issue seeing as we have very similar symptoms and the range in which it occurs.
I believe BMW rate the 02 sensors for 100k miles and my car is knocking on the door of that figure... The problem is, they are expensive, and there are 4 of them... The other thing is the cam position sensors. The problem I have is that usually when these kind of issues occur, there are codes, hell, there are usually codes for vacuum leaks causing lean conditions and stuff, but nothing here!
As for your DMF and clutch... I'd be interested to see what happens here and whether actually this weird misfire-type behaviour is due to some weird flywheel imbalance. Probably clutching (lol) at straws here.
