[eksajlee]

I've got 2009 325i (N53, 3.0L, automatic) and after recent Check Engine with Lambda I feel that my car is not performing as it previously was.

It idles and runs very smooth without any juddering but there's definitely less power on lower gears and rpms. When driving to work car seems to rev way higher to achieve my usual speeds than before. Sometimes I feel like it downshifts 2 gears to actually accelerate quite linear and that's when I'm at 40-60mph.

Also it feels like I need to constantly drive in 4-6K rpm range to actually have a decent acceleration and follow less powerful cars on the road. Engine screams but it doesn't really "move".

I've diagnosed my car with Inpa multipe times and there's no error, and all of the values for vanos, injectors, throttle pedal position, maf etc. looks accurate.

My timeline over last month:

1) Changed plugs
2) Vanos (sensor 1, bank 2) error shows up
3) Cleaned and switched vanos around - no errors afterwards. Cleaned MAF
4) Five NOX errors and two o2 sensor errors - car have less power due to Check Engine
5) Replaced NOX and reset nox/fuel adaptations, replaced lambda sensor. No errors anymore, but car doesn't seem to have it's previous low-end power
6) Changed oil and oil filter
7) Reset all engine adaptations


Any thoughts? I'm running out of ideas as it's really hard to pin-point problems without any errors visible :

[Elias_E90]

Does the n53 have disa valves ?

[eksajlee]

Nope, no DISA valves.

I'm wondering if this could be some kind of intake leak, but it's really strange that the car drove 100% fine until o2 sensor code, and even after replacing it with an OEM it's not quite there.

I've quick-tested 0-60 mph times yesterday with a timer and the time was ok.

[Elias_E90]

A vacuum leak would be felt whenever you hit the throttle and on idle. However if you wanna test for vacuum leak, you can start your car and spray carburator cleaner in the engine bay arround the intake. If the idle flutters you have a leak

[eksajlee]

yeah, I'll give it a go. Need to buy some spray - like a starting liquid.

Had a talk with a technician from a local garage and he suggested that this could be caused by camshaft sensor

[eksajlee]

I've sprayed it and there's no leaks.

Funny enough I think I've found the issue after reseting engine adaptions.
Day after car throwed half CEL and codes and the limp mode felt exactly like mine situation - kind of like hidden limp mode. Anyway codes were:

2CF6 - Throttle valve potentiometer 1, plausibility to air mass
2CF7 - Throttle valve potentiometer 2, plausibility to air mass
2D09 - Throttle valve

After resetting the codes and performing throttle adaptions (press gas for 10 on ign on) it seemed to be fine - and car drove actually as it should!

But... Half CEL is still showing up randomly and it throws 2CF7 - Throttle valve potentiometer 2, plausibility to air mass.

Resetting throttle adaptions with pedal doesn't seem to fix for very long. Thoughts anyone?

[Phyrexia]

The N53 325i does have a multi stage intake manifold and thus a pair of DISA valves.

http://www.realoem.com/bmw/enUS/show...diagId=11_4086

I think 2d09 is indicative of a bad throttle body. Maybe it's not opening all the way.

[Phil325i]

Originally Posted by Phyrexia

The N53 325i does have a multi stage intake manifold and thus a pair of DISA valves.

Not in Europe it doesn't. Multi-stage is only on the 330i here. Can't tell where the OP is located...

[eksajlee]

Originally Posted by Phyrexia

The N53 325i does have a multi stage intake manifold and thus a pair of DISA valves.

I think 2d09 is indicative of a bad throttle body. Maybe it's not opening all the way.

It doesn't have it as Phil325i mentioned. I'm based in Europe.

As for the 2d09 it only showed once and the only error that shows up is 2CF7. The only information I can find about this is either about faulty JB4 installation (obv don't have it) or loose throttle body connector - checked mine and it's solid.

[Elias_E90]

Since you logged throttle valve and vanos and injectors etc. Can you log the map sensor ? Maybe it is giving wrong vacuum data

Edit: http://www.1addicts.com/forums/showthread.php?t=1490882
In this thread you find values of map sensor

[Phyrexia]

Originally Posted by eksajlee

It doesn't have it as Phil325i mentioned. I'm based in Europe.

As for the 2d09 it only showed once and the only error that shows up is 2CF7. The only information I can find about this is either about faulty JB4 installation (obv don't have it) or loose throttle body connector - checked mine and it's solid.

Oh those damn diagrams with their whited out components. Whoops.

[gT-BMW]

arent the n53 same as n52? if so arent these engines vacuum less? I think The only way you can get a vacuum leak is from the ccv and hoses.

the brake booster line is connected to a vacuum pump I had a hairline crack on my brake booster hose, it didnt effect idle or part throttle but my brake pedal felt more firm after the fix.

[Blueeyesredpanda]

Originally Posted by gT-BMW

arent the n53 same as n52? if so arent these engines vacuum less? I think The only way you can get a vacuum leak is from the ccv and hoses.

the brake booster line is connected to a vacuum pump I had a hairline crack on my brake booster hose, it didnt effect idle or part throttle but my brake pedal felt more firm after the fix.

N52 and N53 are completely different. N53 is Direct injection

[Xencer]

Originally Posted by eksajlee

I've sprayed it and there's no leaks.

Funny enough I think I've found the issue after reseting engine adaptions.
Day after car throwed half CEL and codes and the limp mode felt exactly like mine situation - kind of like hidden limp mode. Anyway codes were:

2CF6 - Throttle valve potentiometer 1, plausibility to air mass
2CF7 - Throttle valve potentiometer 2, plausibility to air mass
2D09 - Throttle valve

After resetting the codes and performing throttle adaptions (press gas for 10 on ign on) it seemed to be fine - and car drove actually as it should!

But... Half CEL is still showing up randomly and it throws 2CF7 - Throttle valve potentiometer 2, plausibility to air mass.

Resetting throttle adaptions with pedal doesn't seem to fix for very long. Thoughts anyone?

The potentiometer in the throttle valve tells the DME the position of the throttle valve. I am pretty new to diagnosing BMW specific codes but plausibility to air mass seems like the DME recognizes that requested air mass differs from actual air mass and is blaming it on the throttle valve not operating properly. I think you should try swapping the throttle body. There are 2 potentiometers in the pedal assembly and 2 in the throttle body on a modern drive by wire system. This way, if half the circuit fails, you can limp the car home.

[JuniorB]

Looking at your first system about the vanos codes, if you swapped them with no difference, you may have the dreaded worn ledge. This is a major issue with the n54 cars, the n53 is the same. The vanos will pull timing if these are not up to parameters. This may be nothing, but an half engine code is a common issue with the n54 minus the turbo system.

[eksajlee]

Thanks for your all feedback so far, car was quite alright for a while but issue with half CEL came back after a while few times.

At first I had:

1) "2CF7 DME: Throttle-valve potentiometer 2, plausibility to air mass"
2) On cold start revs would drop down below 500rpm once before settling for the normal idle

I've reseted Throttle body adaptions and over the weekend. I've disconnected and cleaned thoroughly TB and it's connector - after this car pulled great and I thought I've fixed my issue but errors came back 2 days after...

2A0E - DME: Exhaust-gas recirculation valve; control deviation
2A0F - DME: Exhaust-gas recirculation valve; adaptation
2C3E - DME: Oxygen sensor 2 before catalytic converter; line fault I've replace this sensor month ago due to o2 sensor errors!
2CF7 - DME: Throttle-valve potentiometer 2, plausibility to air mass
2D64 - DME: Monitoring, stoichiometric mixture

I'm puzzled... Would the faulty throttle body trigger other errors related to air? It all started with 2CF6 and 2CF7 (Throttle valve potentiometers) and now it triggers EGR error, my mixture is probably wrong as my car mpg is way lower...