[freebo86]

I figured I ask in this forum as it seems to be quite active, even tho my bmw is not a E90 its an X3 but shares the same engine N52. Since both items I believe are engine related I was hoping I would get some luck in here so here it goes.

The first item is that randomly, coasting foot steady on gas pedal going let's say 40mph I feel this jolt (push) where the car almost gets a burst of power. It happens randomly and so quick that I rarely get a chance to look down at my engine rpm fast enough to see how they are behaving during this occurrence. This appears to be completely random and no specific time or gear I am going. My X3 is a 6speed manual.

The second item is, and I find this ironic since my old E46 did the same thing. During cold days in the morning the first start the car starts - then a few seconds later dies. I turn the key it fires up like nothing and runs flawlessly no issues. Not sure what this could be related too.

I scanned the car with ISTA and the only error I get is the eccentric sensor.
2A31 DME: Valvetronic: eccentric shaft sensor: guide
2A47 DME: Valvetronic: eccentric shaft sensor: plausibility

Some items done on the car in the last year worth mentioning that one might question;
New ground straps
New Battery
Cleaned MAF
New Spark Plugs NGK #6619 LFR6AIX-11
Vanos Solenoids cleaned (intake ones);
Changed diff fluid in front and rear
new transfer case fluid
new transmission fluid
Replaced water pump and thermostat (new coolant of course)
typically oil change

The car drives great overall, besides these two items I listed and no other codes are shown when scanned. No lights on dash either. Looking up the eccentric shaft sensor symptoms I am not sure if this is caused by that but I will have to address that in the spring to eliminate it..

Hoping someone can shed some light for me on these two items!

[Blueeyesredpanda]

Originally Posted by freebo86

I scanned the car with ISTA and the only error I get is the eccentric sensor.
2A31 DME: Valvetronic: eccentric shaft sensor: guide
2A47 DME: Valvetronic: eccentric shaft sensor: plausibility

new transmission fluid

Apparently you need to replace your eccentric sensor.

Symptoms:
1. Rough start during COLD weather
2. Take off the engine cover and pull out the eccentric sensor cord. If there's oil in the sensor and the cord, then you definitely need to replace it. You can leave it unplug for now. It will run smooth.

Another thing is replace the transmission fluid filter too.

[freebo86]

Originally Posted by Blueeyesredpanda

Apparently you need to replace your eccentric sensor.

Symptoms:
1. Rough start during COLD weather
2. Take off the engine cover and pull out the eccentric sensor cord. If there's oil in the sensor and the cord, then you definitely need to replace it. You can leave it unplug for now. It will run smooth.

Another thing is replace the transmission fluid filter too.

Thanks for your response. The vehicle can be driven with the sensor unplugged? Are you sure about this? Would the sensor be the jolt/burst of power issue I am seeing?


Also, no transmission filter, I have a 6speed manual.

[Blueeyesredpanda]

Originally Posted by freebo86

Thanks for your response. The vehicle can be driven with the sensor unplugged? Are you sure about this? Would the sensor be the jolt/burst of power issue I am seeing?


Also, no transmission filter, I have a 6speed manual.

I am sure about this because I have doing this since Dec. Drove over 1500km during Christmas visiting families. Also people here have driven the car while it's unplug.

Or you can get a bottle of connector cleaner to clean up the cord and inside the sensor to dry after Every one to two drive because the problem would come back again due to oil leaking to the cord.

I will be fixing it tomorrow or the day after.

[freebo86]

Originally Posted by Blueeyesredpanda

I am sure about this because I have doing this since Dec. Drove over 1500km during Christmas visiting families. Also people here have driven the car while it's unplug.

Or you can get a bottle of connector cleaner to clean up the cord and inside the sensor to dry after Every one to two drive because the problem would come back again due to oil leaking to the cord.

I will be fixing it tomorrow or the day after.

Well thanks for that! I'll be sure to unplug it this weekend and test out how it runs without it.

[freebo86]

Well got around to unplugging the eccentric shaft sensor connection. And wow, the X3 runs better. The throttle response is there, the car feels like it has guts again. Guess my sensor is faulty so I'll be sure to replace it in the spring time. For the time being I am driving with it disconnected - to my understanding the intakes are at max currently and probably resulting in higher MPG?

Also, this seemed to have addressed my issue about getting that random boost of power.

[hassmaschine]

No you're not getting higher MPG. it's running in a form of limp mode - I think max RPM and performance is slightly reduced (but not as dramatically as some limp modes) - it's just using the throttle to control engine speed rather than valvetronic.

If anything, the increased pumping losses from the throttle will reduce MPG.

It should at least be safe to drive until you can replace the sensor.

[freebo86]

Originally Posted by hassmaschine

No you're not getting higher MPG. it's running in a form of limp mode - I think max RPM and performance is slightly reduced (but not as dramatically as some limp modes) - it's just using the throttle to control engine speed rather than valvetronic.

If anything, the increased pumping losses from the throttle will reduce MPG.

It should at least be safe to drive until you can replace the sensor.

Limp Mode? If this is limp mode then I'd like to know what its like in 100% lol. Cause honestly, the throttle feels nice and smooth, responsive. Torque is there too.

Mind you, my X3 is a 6speed manual..

[hassmaschine]

Yeah I forget the exact number but RPM is limited to ~6400 or something instead of the stock 6900.

[Volasko]

Why wait until spring? Swapping the solenoids is about as easy of a DIY job as you can get. I could do it under 10 mins on the side of a the road with the right wrenches. Unless you need to wait that long to save up for one. If that's the case wtf are you doing in a BMW?

[.RJ]

Originally Posted by Volasko

Why wait until spring? Swapping the solenoids is about as easy of a DIY job as you can get. I could do it under 10 mins on the side of a the road with the right wrenches. Unless you need to wait that long to save up for one. If that's the case wtf are you doing in a BMW?

Not the eccentric shaft sensor.