HI.
08 528Xi started running poorly so I did diagnostics and it gave me the 2D06 eror. I then replace MAF sensor. Minor improvement on running/idling but not right. So I pulled codes again and now get 2EF8 (map-controlled Therm) .
Before I got replacing anything, I was hoping to hear some opinions.
Could the Map controlled thermosat cause the idling/running issues?
Maybe it is sending info that makes the MAF not know correct info?
Any insight could help.
Thanks
B
yes, believe it or not a faulty t-stat will signal the dme to do all sorts of strange things. I am not saying its your problem but I have seen this happen a t-stat will trip a air flow code and what not.
when in doubt change it out..... t-stat is easy as well is pump if done at same time. and I recommend both at same time....
Level 1 Certified BMW tech.
OK, I replaced the T stat housing. This made the car run at normal temp. While I was at it, I replaced the valve cover gasket and fixed the oil leaks on the filter housing.
my only problem now comes back to the mass air system fault. If I erase the fault code, it will run ok for a while. If I turn off the car and restart, it comes back and runs really bad with multiple misfires etc... Which go away when I erase those codes and will drive fine till I restart again.
I have pulled, cleaned and tested the Vanos solenoids. No change. I will be checking again for a vacuum leak soon. I cant think of any other reason it could be running so bad and keep giving the mass air system error. Could it possibly be another bad maf sensor? I already relaced it with a Continental.??
Any help would be appreciated.
thx
OK guys, I was organizing my tool box and was reminded that I have tried 3 MAF sensors now. The original one, a cheap one off amazon and then a Continental(like stock) sensor. All of these MAF sensors, when installed cause my car to run like crap and throw a mass air system error code.
Can anyone hazard a guess what else could cause this error? I need a list of ideas to chase after when I can get into my shop. Too cold out now, so I gotta get into the warm shop. I will try looking for a vacuum leak again.
B
Vacuum leaks will cause intake air to bypass the MAF causing low MAF readings, which can cause MAF codes.
OK guys, Im not too smart! I decided to put the smoke machine on again just to be sure I don't have a vacuum leak. Well this time I left it on for over 5 minutes and just when I was about to shut it off, smoke appeared from behind the crank pulley! Then it dawned on me that looking back all my problems started when I blew the belt last summer. DUHH! Sure enough, I pulled the crank pulley and there was pieces of belt shoved right into the front crank seal!!!
So its all fixed now, and I even pressure washed the front of the motor since it was a mess. DIY this job is not bad, but be prepared to struggle to get the old seal out! I used 2 different BMW seal pullers and it would not budge. I had to chisel it out and be as careful as possible to not damage the surfaces. Real PITA, but all fixed and car runs good again.
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