The ongoing Reduced Power Warning mystery... HELP!

[Revnato]

I recently bought a 2012 carbon black x5m from this forum and it has given me nothing but nightmares since the day I bought it. Since the first day it was unloaded off the transport (from Maryland to CA), it has had a check engine light. The previous owner had all eight of the fuel injectors replaced before I bought it and claimed the car was in perfect working condition. The first time I floored the car, it immediately threw a check engine light and went into reduced power mode.

I had the car inspected by the Santa Barbara BMW, Rusnak Thousand Oaks BMW, and lastly European Auto Source. None of them could figure out what was wrong it. EAS told me it had to be the spark plugs or something ignition related. So, I had them replace all eight spark plugs and ignition coils. That means the car has a completely new ignition system (plugs + coils + injectors).

Immediately after leaving EAS I floored it while merging onto the freeway and guess what happened? Yep, you guessed it... check engine light with a reduced engine performance mode. EAS inspected all of the vacuum lines as well and said they all looked fine. So at this point its a mystery what it is, and a very expensive mystery at that.

In hindsight, I realy wish I would've done more research on these cars. I would've never bought this big peace of useless metal knowing that some of them have this issue that, as far as I've read, has no solution.

I think its worth noting, I have an AWRON Digital guage installed. Normally when the car is running the way its suppose to, the boost measures up to around ~19psi (I have catless downpipes and a tune as well). When it goes into reduced engine performance, i get 8psi boost max.

Does anyone have any idea what it might be? Two of the top mechanics in SoCal have yet to figure out whats wrong with it.

SOMEBODY HELP ME PLEASE!

[Cattivo]

Are you getting an CEL every time you floor it? have you noticed if you're engine is up to temp when the CEL comes on? I have a tune and dp's as well... I get a CEL only when the engine is not up to temp which forces me to pull over and re start the truck. The truck runs great after the engine has reached operating temp

[racermp]

What's the code?

[badge1]

I have had this happen one time only. I floored it shortly after powering up and the engine was not yet up to temp. Got reduced power. Turned it off, and haven't seen it since. Hopefully it's as simple as that.

[Poppyboy]

Might it be worthwhile to bring everything back to stock as much as possible?

[windsailor]

I had the first of those about a couple of months ago, 30' coffee stop and back to highway, floored and middle finger from the engine with diesel blow style smoke puff from exhaust, had to pull over and turn it off and back again on, CEL gone and truck back to normal.
Relief, yes but, still checking for a possible come back on this front. Stage 1 and OEM else.

[azm3]

I have been getting check engine lights then reduced power mode on my X5 50i with Code: 002D21 (Mass air flow sensor, working range: Period too large, air mass to low) under full throttle at the top of gears.

Seems my air filters are restricting things too much. Just ordered some drop in's from n63intake.com, hopefully it solves my problem...

Have you checked your air filters and MAF for buildup?

[Cattivo]

Originally Posted by azm3

I have been getting check engine lights then reduced power mode on my X5 50i with Code: 002D21 (Mass air flow sensor, working range: Period too large, air mass to low) under full throttle at the top of gears.

Seems my air filters are restricting things too much. Just ordered some drop in's from n63intake.com, hopefully it solves my problem...

Have you checked your air filters and MAF for buildup?

Are you replacing the filters yourself in the 50i? I seriously hope you have lots of patience and 8-9 hours to kill

[azm3]

Originally Posted by Cattivo

Are you replacing the filters yourself in the 50i? I seriously hope you have lots of patience and 8-9 hours to kill

I have heard it is a fun job. Luckily a good friend of mine owns an inde BMW shop here in Scottsdale and they have done quite a few.

Also planning to install catless DP's at the same time, they are estimating about 5 hours for all of it, I am sure it would be 8 if I help. The PDF guides I have seen do not look bad, but more than I want to try to tackle in my garage...

[frankenm]

http://www.xbimmers.com/forums/showthread.php?t=1260684

We have an on-going discussion about this reduced power issue ... alot of people have this problem in the X5M