BMW Forums : BimmerForums banner
1 - 8 of 8 Posts

Registered
Joined
4 Posts
Discussion Starter · #1 ·
Hi guys. I'd need suggestion as my car driving me crazy last 10 days. Car is 520d 2011 184hp egr and dpf mapped out, and with 214hp now since 2020, never issues until now
Car has huge hesitations on low revs, doesn't react on throttle for 2 3 sec then power comes back, but loses power couple seconds after. There is misfire(I think) from time to time when stationary, you can hear engine changes sound and revs start jumping up and down for 4 5 sec from 550-850 then goes back to normal. Unburned fuel on the exhaust, black smoke on heavy acceleration. Shaking, choking, vibrating, stalling on acceleration on 1000-1500 revs, any word you think of that doesn't sound good will describe it... slight vibrations when revs go above that one but still you can feel it. No lights no codes. All symptoms above dissapear once I have MAF sensor taken out, and I was driving for 2 days without it to see will anything come back, nothing, perfect driving car. So I got new MAF sensor, cleaned MAP sensor, new air filter etc... As soon as new MAF sensor fitted, everyhing came back all problems. So, long story short, car has no issues at all without MAF sensor, and feels like cylinders gonna come out thruogh bonnet once you have it back. Any suggestions? 馃檹
 

Registered
Joined
4 Posts
Discussion Starter · #3 ·
Have you checked for any air leaks?
Did, haven't been able to find any... Went to mechanic, told him everything, he said he reprogramed maf sensor and it really appeared it worked for some 20 30 mins, but then all problems came back. Forgot to mention, all symptoms starts once engine heats up, nothing while its cold, so first 10 mins from start is all ok
 

Super Moderator
Joined
3,894 Posts
You say that EGR is mapped out but those symptoms sound very much like a failing EGR valve could cause. The mapper has obviously erased many trouble codes from DDE, could be even some relevant ones which always make diagnostics a nightmare.
 

Registered
Joined
4 Posts
Discussion Starter · #5 ·
You say that EGR is mapped out but those symptoms sound very much like a failing EGR valve could cause. The mapper has obviously erased many trouble codes from DDE, could be even some relevant ones which always make diagnostics a nightmare.
Thanks for your reply. I'll go back to mechanic on Monday and have that one checked too, have to find what is the reason obviously, hard to find if its something connected with missing codes... What would be a better option then for a day or two of driving, with MAF sensor plugged in and run it with all jerkings, or unplugged it and drive it 'without issues', possibly just masking some other issue that cause all of this?
 

Registered
Joined
55 Posts
Thanks for your reply. I'll go back to mechanic on Monday and have that one checked too, have to find what is the reason obviously, hard to find if its something connected with missing codes... What would be a better option then for a day or two of driving, with MAF sensor plugged in and run it with all jerkings, or unplugged it and drive it 'without issues', possibly just masking some other issue that cause all of this?
Leave it unplugged.

I agree, it is probably the egr valve and the maf is used by the DDE to control it.
 

Registered
Joined
180 Posts
EGR fault.
Other considerations are MAP sensor ,Exhaust pressure sensor.
EGR, MAP,MAF and DPF pressure sensor all work in harmony with each other.
I have experienced this very same fault and replaced all the above in order to rectify. .

50 years an engineer.
 
1 - 8 of 8 Posts
Top