My '01 4.4 is freaking out...
 

Firstly I have to say that this is by far the most informative forum for the e53. I have done some searching, but nothing fit what was going on with my car.

Ive had the car for a while now, and it has been sitting in the garage for about 6 months 'till i finally decided to use it. I jump started it since the battery died and the engine light came on. At first i thought it would clear itself up since the car has been sitting for a while, and I even took the car in for a service just in case and the only thing they changed were engine oil and brake pads and rotors.
Now the issues:
If I ever leave the car off for about 1 hour or more,

-I would turn it on and the AC would automatically come on
-Everything in the navigation system would go back to the way it was 6 months ago..meaning all addresses i have entered since the jump starting is deleted
-CD changer would freeze up and i would have to take it apart to fix the issue (not always, but 3 times in a week so far)
- tilt steering doesnt go up and down anymore, just closer or farther.
-If the gear is on P, if I lightly tap the gas and the rpm would go up to just under 1,000, the car would die out.
- The engine light would stay on for 2 days or so, but then would be off for less than a day before coming back on.


However, the seat memory still works and whenever the AC turns on at startup the temp. on the ac is the same as i last left it.
I have taken it to a shop and he told me there are 0 fault codes.
Im guessing I might have fried something when i jump started the car.
Could it be the alternator that is damaged because of a faulty jump?
Battery perhaps?


Any insight is greatly appreciated because it is driving me nuts:banghead::banghead:

Jump starting it could have fried the ECU's but you need to diagnose the problems individually as some are the normal result of the car being left standing for a while and others due to the fact the self learing memory has been lost, and it may well improve with use.

I would change your battery mate.
A dodgy battery can cause all sorts of strange electrical problems.

If you had fried your ECU it probably wouldnt start at all.

Agree...change battery.

changed the battery and the engine light went off so thanks guys i really appreciate the help.
only issue is
-that the Nav and AC problems are still there..doesnt bother me very much
-when i tap the gas lightly, the engine doesnt go off, rather it dips reallz low then battery light comes on and RPM shoots up just like when the car starts. Electrical or mechanical problem??

My last question is, the hose that connects to the top of the airbox (not the cold air feed or the MAF)..this hose goes down to what appears to be a pump that then connects to the engine block. What is this hose used for?
I want to get a CAI and i have not seen any intake system that incorporates this hose. Any input would be greatly appreciated!

This is because your sensors have been reset. If it doesn't clear up after a few days of driving you will likely have to replace the MAF. When the car ECU hasn't been reset it runs off a cache file of information it uses as a baseline and only changes mildly during driving. With the ECU reset from the battery change you can always find a bad MAF if the truck does what you are saying and doesn't come back around after a few days of learning the MAF again. Learned that the hard way on my Mercedes CLK 430. I have made this bet with people and won every time.

Excellent ill give that a try.
Should i buy a Bosch MAF or Geniune BMW? Is there much of a difference?
Im probably gonna source it from ecstuning.com as I have dealt with them before.
Also,
Just today when i turned the car on, the outside temp reading changed from Celsius to Fahrenheit. Weird. Also, later today the engine light came back on. Its really starting become annoying.

Should I disconnect the battery for 30 mins to reset everything?

Any takers?

Bump...Anyone who would like to help?

bump

A common AC problem is the Final Stage Resistor. It's an easy DIY replacement and there is a good article here. Do a search for FSR.