Update Apr-23 to Aug-23:
Let's start off with a short review of the ride and handling after having done the Comp springs, as well as the new PS 4S tyres. Now bearing in mind, I don't do a lot of mileage, and that which I do manage to rack up, is mostly short trips. So yes, for the school trip, no issues, for the shopping trip, no issues. Overall, I haven't been caught out anywhere, and I haven't seen the DTC light of late. SO I would tentatively state that mechanical grip has improved with the new rubber.
Where things have changed quite noticeably, is in the ride comfort. With the Comp springs, ride height is lowered by 10mm officially. My crude measurements before and after show this to be more, although the new tyres (with slightly different profile) will also contribute to this somewhat. The car is noticeably firmer, so much so, that even the driver's door will creak from time to time when hitting a bump. Speed bumps are also now more of an obstacle than before, and require some negotiation at times. If I were to be critical, I would say that this has moved the car down 1 notch as a comfortable daily, in a similar vein to how the Akra exhaust is noisier compared to stock, the same can be said with the Comp springs compared to the stock springs in before that.
But, in the context of the car, this is the Athlete of the E90 range. Offering superior performance and driving engagement compared to the other models, so looking at it in that context, means it is now a more focussed athlete. Don't get me wrong, the car is still usable, and is still used in the same manner as previously.
On to some maintenance items which all got done in July. The headlight switch was on its way out over a year ago already, where the switch would only work from the Off position, to the Auto position, it would not work turning it the other way to switch on the lights manually. I ordered a switch with BMW Midrand last year, but there was no stock, and needed to be manufactured by BMW’s supplier. So the switch only arrived locally this year.
Fast-forward to July, and after some researching on how to do this, I set about the job. All-in-all, it took about 10mins of working carefully with my trim removal kit. Some pics below:
Over the past few months, there has also been a noticeable degradation in the cold start procedure. As time has moved on, the car got more finicky moving from the cold start cycle into normal operating mode. Initially, a fault would pop up every couple of weeks, which then lead to more and more faults. The car would begin to misfire for about 2mins, before settling into a stable idle again. It got to a point where starting from cold and driving off, would see us limping down the road, with no power at all. Scanning the car after the fact showed that it was misfiring on 4/8 cylinders. Who would’ve thought that you could literally walk faster down the road than a 4l V8 could manage driving in this state.
Interestingly, even though the faults were showing that a misfires were present, there were no supporting faults related to coil packs, spark or ignition. The supporting fault codes (18 in total at one point) all referenced the O2 sensors on both cylinder banks.
Some more shopping and research, and I ended up importing 4x Bosch O2 sensors, with the OEM part numbers specified. This was a R12k exercise. Cough cough.
Once they arrived, I had a gap and decided to get the car onto the ramps and change out the sensors.
Before starting the job:
The new sensors, grey at the front, black at the back:
Interestingly (or rather annoyingly), the one sensor had a much longer wire than the one that came off the car. So I had to get creative in trying to tie up and package this extended wiring under the car. With hot exhausts on one side, and a hot gearbox on the other side, space for securing the wiring was limited. Nevertheless, managed to get it done, and hopefully it all holds up.
While the car was on the ramps, I went ahead with an oil + filter change, and also washed the air filter.
The last step in the process was to use ISTA to reset the service indicators, clear all fault codes and I also reset all the adaptations.
The end result, the car started and idled perfectly, and there have been no issues moving into the normal operating cycle. No more fault codes, no funny sounds. The car even idles at a steady RPM, whereas previously it did used to hunt up and down, with the occasional misfire / blip in smoothness. It was an expensive maintenance item, but glad it’s done as the car is all the better for it.
Then as usual, I attended the 3rd BMW CCG Skid Pan event for 2023. This was literally the day after replacing the sensors and doing the service, so it was a good excuse to run in the new parts. On this particular day, I was making friends with a few of the cones on the course. Nevertheless, great fun as always.