Hello,
I´ve had my 2006 2.5si since the start of the year and I have a strange symptom happeing to me during long drives (longer than 60-90 minuts).
What happens - after driving for these longer periods the car suddenly develops a weak spot on acceleration between 3000>4500 RPM. It pulls but seems to be lower on power in that range, the acceleration is uneven and the sound is a bit strange as well - a bit louder and intermitten (no misfire codes ever). Above 4500 it pulls normally and bellow 3000 seems normal as well. The problem goes away once that car cools down within a few hours. And it isn´t throwing any codes besides once giving me a 2A87 code.
Only other symptom that the car has is a little rough idle after cold start (fluctuates +-100rpm)..... and maybe a tiny little bit of hesitation/uneven acceleration in slow speeds between 1500-2500rpm, but that might just be the quick throttle response, shaky foot on bumpy road surface and paranoia...
What I´ve done so far since purchase -
- New small DISA (the one on the inside of manifold - OEM from BMW)
- New MAX (OEM)
- New solenoids (Pierburg)
- New PCV - improved oil consumption - was 1L per 1600km - now seems to be 1L per 10 000km (estimate so far 3000 km ate 250ml)
- Cleaned vanos check valves - made cold idle much better (originally fluctuted more and even after some driving)
- Changed oil once so far
- New gaskets for oil cooler, intake manifold, oil filler cap
The vanos solenoids was my most recent attempt and I was hoping that might resolve the rough cold idle as well, but that hasn´t materialized - might have made it a tiny bit better perhaps...
So I am a bit lost for ideas. I´ve been struggling to find anything similar to my issue but haven´t found anything online. I asked fellow Z4 folks on Facebook and got an interesting suggestion that it could be some dirt in the gas tank that gets sucked into the pump after the longer drive and clogs up the filter... but how would that only affect the 3000-4500 rev range?
The obvious thing to me was DISA flaps. As far as I know the smaller one opens at 3000 rpm and the large one at 4500 rpm. However I had the issue come back after having the small one replaced.
I guess the vanos is also readjusting things from 3000-4500 so it might be other vanos related things such as Eccentric Shaft Position Sensor somehow failing after longer drive?
In summary I don´t really know where to look next and with no fault codes poping up its hard to track. So I was just wondering if anybody ever had a similar issue and found a solution?
Cheers!
I´ve had my 2006 2.5si since the start of the year and I have a strange symptom happeing to me during long drives (longer than 60-90 minuts).
What happens - after driving for these longer periods the car suddenly develops a weak spot on acceleration between 3000>4500 RPM. It pulls but seems to be lower on power in that range, the acceleration is uneven and the sound is a bit strange as well - a bit louder and intermitten (no misfire codes ever). Above 4500 it pulls normally and bellow 3000 seems normal as well. The problem goes away once that car cools down within a few hours. And it isn´t throwing any codes besides once giving me a 2A87 code.
Only other symptom that the car has is a little rough idle after cold start (fluctuates +-100rpm)..... and maybe a tiny little bit of hesitation/uneven acceleration in slow speeds between 1500-2500rpm, but that might just be the quick throttle response, shaky foot on bumpy road surface and paranoia...
What I´ve done so far since purchase -
- New small DISA (the one on the inside of manifold - OEM from BMW)
- New MAX (OEM)
- New solenoids (Pierburg)
- New PCV - improved oil consumption - was 1L per 1600km - now seems to be 1L per 10 000km (estimate so far 3000 km ate 250ml)
- Cleaned vanos check valves - made cold idle much better (originally fluctuted more and even after some driving)
- Changed oil once so far
- New gaskets for oil cooler, intake manifold, oil filler cap
The vanos solenoids was my most recent attempt and I was hoping that might resolve the rough cold idle as well, but that hasn´t materialized - might have made it a tiny bit better perhaps...
So I am a bit lost for ideas. I´ve been struggling to find anything similar to my issue but haven´t found anything online. I asked fellow Z4 folks on Facebook and got an interesting suggestion that it could be some dirt in the gas tank that gets sucked into the pump after the longer drive and clogs up the filter... but how would that only affect the 3000-4500 rev range?
The obvious thing to me was DISA flaps. As far as I know the smaller one opens at 3000 rpm and the large one at 4500 rpm. However I had the issue come back after having the small one replaced.
I guess the vanos is also readjusting things from 3000-4500 so it might be other vanos related things such as Eccentric Shaft Position Sensor somehow failing after longer drive?
In summary I don´t really know where to look next and with no fault codes poping up its hard to track. So I was just wondering if anybody ever had a similar issue and found a solution?
Cheers!