saintz

First guess around tranny downshift is it's learning your driving style. Do you drive like a Grandma most of the time and then only randomly floor it? I'm guessing not.

From reading, it seems the two most common power losses are MAF and then clogged cats. If a battery reset restores power, it's not clogged cats. MAF seems likely. Do you have K&N or other oiled filters in the car? Can you locate the ECU/TCU (should be under the hood, passenger side, near the windshield, in a black plastic box, I believe) and verify there's no oil in there or on any of the wiring looms. Sometimes oil can leach in on the TCU loom and cause issues.

I think I saw a post by a guy who's MAF kept going bad repeatedly. That may lend some insights. I'll try to look for it.

Benz-O-Rama

Don't be mad but my E500 ran the 1/4 in 13.49@102.5

Not a gtech run, an actual drag strip run. I thought the W210 E55's were 12 second cars, stock.

Then again, my car is quite modded.

Glad to see your car is running strong again.


**EDIT**

Just looked it up. Looks like low 13's stock. Look out boys, I'm gunning for ya.

amgalex

Thats good times man!
Im not planning to stay stock for too long though so

amgalex

My filters are stock.
I know reset of transmission helps a little, but in this case its definitely a power loss and not a transmission issue.
I will check for oil or dirt on the ECU itself.

I'm suspecting our intake that just sits on top of the MAF might potentialy cause problems. Maybe air is sneaking by the MAF into the system and than 02 sensors pick this up and readjust air fuel ratio by adding more fuel to system by this reducing MPG and reducing power output.
I had taken the intake and MAF off today and put some electric tape on each end of the housing for a tighter fit and less potential for air leaking. Now I have to see in a week or so if the ECU readjusts itself again and lowers hp output.

saintz

Do you smell fuel at the tailpipe? As in running rich. I don't know an easy way to check if you're running lean.

amgalex

well the weird thing is that I don't smell fuel even when power was down by 100hp .
so maybe:
1. cats are doing a very good job and burning exess fuel off?
2. Ignition timing is getting pulled by a lot?
3. fuel is being pulled to prevent engine damage because of out of whack 02 readings??

MaxVon

I'm really interested to see where this goes. I'm so frustrated with this condition in my car. I love it when it's "The Beast" but so disappointed by having to disconnect the battery every few days to keep it alive. What's going on? It performs like a E430 when out of proper tune. Maybe it's a bad ECU that can't hold the tune? Let's fix this!

amgalex

Yes lets combine info and get this figured out.

armaniE55

My 55 cents:

Unlike the newer W211 which also adapts to your driving style but won't notice "granny mode" as much on a W210. I'll chime in due to the fact that I have the AMG Spring Booster. Most W210 Owners won't really feel any difference on take off or the car shifting gears to early. There's another write up on this if you do a search. (Conclusion) If you drive the car let's say slow for two days the ECU will automatically pick up on your Slowness driving hence granny mode unless you drive like a Freak 24/7 Leerod than you won't notice a difference also if you start to pick up the speed again it will slowly start to adjust. The W211 obviously has newer technology and I haven't heard/read any issues w/those guys

Trintony - Follow his directions this is what I do whenever she feels a little sluggish. I let the wifie take the Beast once in a while and I would notice the difference the very next day. I don't go through the trouble of disconnecting the battery with my personal experience I can turn the Juice back on by following Trintony advise.

-Armani


**Sometimes some tuners will also do the old reset ECU trick when you leave the shop after they sold you 1k off BS stuff ** For the most part you can do the key trick on most cars**

jpohl402

But is the problem lack of a supercharger ?

armaniE55

No N/A...

amgalex

Its not the adaptive mode guys as I had said before. ECU will adjust shift points on the transmission but will not pull power by 50-100 crank hp. I ran test in 1/4 mi and the Key ECU reset does nothing to bring HP back only makes the car shift a little different.

armaniE55

Hmm.. but didn't you state that the car runs like a champ after resetting the ECU by disconnecting the battery?


Are you sure that your loosing that much HP?

amgalex

Yes it runs like champ for 3-4 days than starts to cut power.
Im sure on loosing that much power 0-60 and 1/4 mi times say that.
from:
4.8 0-60 and 13.2 1/4 with 107mph trap after battery disconnected to 6.0 0-60 and 14.5 1/4 mi with 98mph trap after 4-5 days
that's a substantial power loss.

armaniE55

Agree that is a good significant amount HP loss..... I'll see if I can dig up that old Forum it's been discussed before. I still think that your car is fine and it's just the ECU resitting itself.

No CEL Correct?

New MAF installed*

It's not running rich... Can you pull the codes and see if there is anything on there and post back here?

amgalex

No CEL lights
New MAF installed. (Bosch from AZ auto house)

I pulled the codes with an obd2 reader that I own, nothing shows on that.
I forgot to mention; when my car in in park and idling I notice a rough idle at times, maybe this is a sign of a air leak somewhere in the system which contributes to ECU readjusting itself later?

armaniE55

.........

At idle yup my car does the same sometimes.... If you really , really want to know Exactly what is wrong... hate to say but... Stealership might be the only way to go-

Sorry I couldn't be much of help

Good Luck and keep us posted....

-Armani

MaxVon

That's the frustating part. I have had access to a top "stealership" technician with full access to the factory diagnostics tools. This guy is a "car guy" and understands what an E55 should perform like. I had a bad catalytic converter replaced under warranty and then had the MAF go south and replaced that too. The tech plugged my car into the MB factory tool and you could see all the values were spot on including O2 sensors and air mass flow sensor etc. He then reset all the values to factory spec and we went for a ride. He was so impressed with the acceleration and response since he had not driven an older E55. I was so happy that maybe this was the "fix" and my troubles were done. Slowly the performance went back to E430 standards. It seems that this "adaptive" ECU crap is ruining my E55 ownership. I love it when it runs like it should but if I can't get it to run strong like it should....Good Bye!
That's the "rub" owning a somewhat exotic MB. How many MB techs that work at dealerships have and knowledge of the older cars and even care as they are flat rate and want to make the most dollars doing services and brakes and bushings on later models. There is something wrong here. Is it all E55 210"s or only a hand full of us?
I'm going to start with the basics. In all my years working at dealerships (Jaguar, Volvo, Ferrari,Lexus) a lot of issues with perfomance came down to silly things like a bad ground or bad connection. I'm going to start with the battery and work my way out. I am going to disconnect and clean every connection that I can get to without removing the dashboard etc. Maybe it's all a waste of time but I really like the car when it runs like it should.

armaniE55

"adaptive" ECU crap I completely 2nd that.... AMS said it best these ECU aren't made the way they should be. One would think that AMG would acknowledge this issue or was this even brought up to their attention with later models? (Bug Fix) It doesn't really bother me as I don't mind the Key Trick every once in a while but I do think it's a little silly...... (One sec. guys I need to reset my ECU before we race) kinda frustrating in a way... Clearly it's the ECU - Poor design

-Armani

amgalex

I have ordered new gaskets on both sides of MAF housing
I mentioned this before but IM seriously suspecting the lower part of the MAF housing to be leaking air into the throttle body and so bypassing the MAF sensor with air volume unaccounted for. Crossing my fingers here as this would be an easy fix to a power loss issue.
I will keep you guys updated.

jpohl402

Correct, W210 E55's are naturally aspirated....
Perhaps there lies the problem - "lack of a supercharger"
Add one, the car will not feel so slow !!

I got rid of my (W211) E55 a while ago, and if one truly likes N/A motors, my E63 is a suitable replacement....

Just saying - (not trying to be a d*ck)....

amgalex

umm

MaxVon

I wonder if an ECU tune by AMS would cure this condition?

LeeRod80

LMAO!! I just read this...hahaha

Nocturnal-G

Whenever mine acts sluggish, I keep my foot planted on the throttle as much as I can.

Oh... and have you guys noticed the pedal? One minute it's firm, the next it's soft. Mine is firm MOST of the time... which allows for great launches. I hate the soft pedal. What's the deal with that?