phenomxxxx

Greetings all! Happy New Year! I am a new 2000 E55 owner. I am going to do my best to explain the problem. Ive had the car for a few weeks and love it, but suddenly when I punch it, it sputters and then takes off. After reading different threads and forums, ive decided i would start with cleaning the MAF before replacing it. So yesterday I took off the MAF and cleaned it with the appropriate cleaner and put it back on. I went step by step with a tutorial i found and after putting it back together and putting the air box on, i took it for a spin I could tell there was an immediate problem. There was barely any acceleration and the CEL came on. I took it back and took off the air box. I then drove it around the block without the airbox and it seemed to drive ok. I thought maybe the airbox wasnt seated right so i put the airbox back on and sure enough it rode just as rough as the 1st time. I took it off again and drove it without the airbox and again it seemed better. I let it sit overnight and today I put the airbox back on and made sure this thing was on right and it rode like crap. I then took off the MAF again and reinstalled it. I put the airbox on and it runs like crap again. Im just going to order a new MAF but how tight is the elbow supposed to be that holds the MAF? there seems to be some play in it. Also I did take out the filters and clean the airbox and put them back in. I dont think that has anything to do with it. one last thing..there is a small white tube that comes out of the firewall right by the MAF..what is that for? There is a black hose that I think it fits into. any suggestions would be appreciated

Tall Giraffe

I was just down here today so I can chime in. Check codes first. What are they? I have a P0170 currently.

The first thing I do when I clean my MAF is disconnect the battery to reset the air and fuel trim values. If you still have an issue then it may be you MAF as there is no telling how long the MAF has been installed with mileage.

To secure the elbow throttle body/MAF you have 2 seals and the click clamp. The elbow has a lever on the bottom and an arm on top to hold it in place but the clamp assures the tighter fit.

The clamp is tricky. What I like to do is find the metal stubs on the throttle body that the arm holds on to and hold with my hands securely ensuring no movement while trying to get the clamp to click with a flat head by pushing inwards on the 'Z" if you know what I mean. So long as the slots are securely in place, this seems to hold the elbow and MAF pretty securely without much movement.

Check all the hoses for integrity. After 16 years, you will have dry cracking and brittle hoses. The MAF has one on the lower right side and the throttle body has 2 hoses that fit on top downward. Make sure all the plumbing is secure together and down tight. I replaced all my hoses when I did the breather cover seals and leaky gaskets.

I am not sure of the white hose you speak of.

Try disconnecting the battery over night and post back results. The first time my MAF went out I had P0173 and cylinder 300, 400 etc misfires. If the MAF is bad after disconnect and inspect, along with verifying codes, it may be time for a new MAF.

Jan AMG

Buy a new MAF, I had mine cleaned and it lasted only a while and was still throwing CEL, power was decreased by about 5-10% tested on dyno even before the CEL.
Bought a new one (get Bosch, not original MB part which is 100% the same but costs 3x), replaced it and it tears up asphalt like a new car again.

cm60k

..^^Good Advice^^..

;ZAYED;

PJmak

The plastic white tube with a rubber hose on it pluggs into the back of the intake manifold

PJmak

You are talking about the white\black hose coming down to the back of the engine from the top of the firewall right?

PJmak

Youll see in this pic its on the left side(the black rubber hose)

Tall Giraffe

Yesterday I went ahead and changed my MAF. I had a single P0170 code with no other codes. It would come off and on depending on ambient temperatures. 80 degrees would come on, in the 50-75 would stay off. Cleaning it would be successful for a few days then CEL.

The MAF I just removed, I cleaned it every oil change using Pro DRY S Filters cleaned each time as well. It lasted me about 50K miles before it broke down. This new one I will not clean once to see how long it lasts....