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Discussion Starter #1
Hi everyone, I always feel that my car has slower acceleration time (0-60) then a lot of you guys did on the forum....I replaced my MAF about 2 months ago then dis/reconnect the battery, feels much quicker but only last for about 2 weeks then it gets slower again. I tried to do the reset ECU thing and doesnt feel quicker. Last week the check engine light came on and mechanic saids is the O2 sensor problem. I didn't replace it yet and I just dis/reconnect the battery and clear the light. The car is back to quick again. So if I replace the O2 sensor will the car be quick like right after I disconnect and reconnect the battery all the time without dis/reconnect battery every like 2 weeks? or is there some other reason that the car only gives the quick performace after dis/reconnecting battery? Is a 2000 E55 with 110000km on the car now.....no mods except for the x-pipe. Thanks!
 

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i would suggest replacing the o2's as soon as possible. you risk running overly rich or overly lean for an extended period of time. this is not only bad for your gas bill but could harm other parts of your car or motor depending on which condition you are suffering from. Sounds like you are running too rich, how bad is your gas mileage when the car is "not quick"?
 

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Discussion Starter #3
the millage I get is about 18-20L/100km city driving (I am in canada so the display is set on metric) and highway about 14-15L/100km....is it more gas usage then normal?
 

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"I replaced my MAF about 2 months ago then dis/reconnect the battery, feels much quicker but only last for about 2 weeks then it gets slower again. I tried to do the reset ECU thing and doesnt feel quicker."

I have the exact same situation. I replaced my MAF with one I bought from Autohauz AZ and disconnected the battery overnight. Next AM the performance was fantastic! The car absolutely jumped from 60 to 120mph in what felt like 8 seconds. It would spin the tires when rolling at 10mph and flooring the throttle. Just incredible. That lasts about a week and then it's kind of doggy again. Floor it on the highway and it downshifts but doesn't jump up and leap forward, just more engine noise and moderate acceleration. I disconnect the batter overnight and it restores the power again.
I had the drivers side catalytic converter replaced and just had the passenger side checked and it is fine. No codes. Just had my MB tech friend hook it up to the dealers Star diagnostic machine and all the values are spot on.
As much as I love the car I am growing weary of this hit or miss performance. I call it the "Forest Gump E55", it's like a box of chocolates, you never know what you're going to get when you step on the gas! I don't drive aggressively all the time so perhaps the "adaptive" transmisison or ECU is punishing me. I'm not sure if this is acceptable behavior and am considering moving on to another vehicle. Perhaps something with fewer computer controlling issues. Maybe these aftermarket Bosch MAF's are junk? I know they are not remanufactured but my MB tech (18 years experience) said he doesn't trust the ones bought aftermarket. I explained that Bosch is Bosch but he seems to feel the MB has them built differently than the generic Bosch MAF's that fit many applications with one part number. I don't want to pop $350.00 at the dealer just to have the same results. Any thoughts?
 

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...Maybe these aftermarket Bosch MAF's are junk? I know they are not remanufactured but my MB tech (18 years experience) said he doesn't trust the ones bought aftermarket. I explained that Bosch is Bosch but he seems to feel the MB has them built differently than the generic Bosch MAF's that fit many applications with one part number. I don't want to pop $350.00 at the dealer just to have the same results. Any thoughts?
This has been debated before and a lot of people feel the same way your MB tech does. I have also seen at least one very knowledgeable member on here argue that "Bosch is Bosch". I really don't know but I have never heard anything negative on here about autohaus.az. If they sell a part as OEM, then I believe them. The alternate brands they also offer might be questionable.
 

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MAF's an O2 Sensors

You guys are likely suffering from Computer problems brought on originally by a bad MAF. When the MAF goes out it will often throw O2 codes because it can make the cars run rich and ruin the O2 Sensors. The O2 in turn will also screw with the Computer and jack up the mixture programming. Equals bad performace and bad fuel economy. When you reset the Computer it goes into a preset default mode till it has a chance to read the cars sensors. This will take a number of start/stop cycles. Hence your smoke the tires performance after resetting the computer. Once you understand the system and how they work Forrest Gump will be taking a back seat on the bus, If it ever shows up.

Good Luck!:thumbsup:

C as in 220
 

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You guys are likely suffering from Computer problems brought on originally by a bad MAF. When the MAF goes out it will often throw O2 codes because it can make the cars run rich and ruin the O2 Sensors. The O2 in turn will also screw with the Computer and jack up the mixture programming. Equals bad performace and bad fuel economy. When you reset the Computer it goes into a preset default mode till it has a chance to read the cars sensors. This will take a number of start/stop cycles. Hence your smoke the tires performance after resetting the computer. Once you understand the system and how they work Forrest Gump will be taking a back seat on the bus, If it ever shows up.

Good Luck!:thumbsup:

C as in 220
I appreciate the responses. I still don't "get it". All values for 02 sensors, MAF, Air to Fuel ratio where spot on according to the Mercedes Star diagnostic tool. So if the values are correct, how can the computer keep messing up the mixture program? Very frustrating to know all that potential is there and not being able to use it.:surrender:
 

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Ask the shop

I would ask the shop what's the deal that the default learn mode is performing better than normal run mode when no codes are present? The only other thing I might add is MAF's can be bad and NOT CODE. My car got to where it seemed like it was running on 2 cylinders from a bad MAF and NO CODE! Try disconnecting the MAF and run in default mode. See if the performance improves right away. You may have a bad new one. It's rare but I have heard of it happenng.

Good Luck!:thumbsup:

C as in 220
 

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This has been debated before and a lot of people feel the same way your MB tech does. I have also seen at least one very knowledgeable member on here argue that "Bosch is Bosch". I really don't know but I have never heard anything negative on here about autohaus.az. If they sell a part as OEM, then I believe them. The alternate brands they also offer might be questionable.
Hello Musikmann,

On the "Bosch is Bosch" issue, yes I agree that the parts Autohauz.az sells are genuine Bosch items in a Bosch box with Bosch part numbers. The issue my tech brought up is that the part Autohauz sells from a Bosch parts distributor is made for many different automotive applications. It may fit our E55's as well as a 2005 BMW 5 series. He theory is that MB makes a dedicated part for the their cars with certain tweeks that are recognized by the ECU and where a generic Bosch part will not have that tweek and affect performance. When I had the OEM MAF when living in CA the car ran like a beast all the time. Only when I moved to Boston and had a catalytic converter go bad then the MAF go south have I had this issue...:dunno:
I'll see I can find an O.E.M. MAF at a bone yard and try that maybe?
 

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Discussion Starter #10 (Edited)
so the best solution is to go for the MAF from dealer? or changing the O2 sensor will help? I have already ordered the O2 sensors it should be on the way.....hopefully it will really help. btw before I got the new MAF 2 months ago I cleaned my original one and then the car runs like as it should too (very powerful)....then I got the new one that I have now after a couple of weeks and before that the "cleaned" old sensor is still doing great....maybe I should put that back on? or maybe I should just disconnect the battery at nite and reconnect back every morning =D
 

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the millage I get is about 18-20L/100km city driving (I am in canada so the display is set on metric) and highway about 14-15L/100km....is it more gas usage then normal?

Your fuel consumption seems very excessive, I get a mixed highway/ city at 55km/hr ave of 9.7ltr/100km and slow city stuff, Brisbane OZ at 28km/hr ave 13.5ltr/per 100km. I found my car also sluggish a while ago but could not find anything wrong thn I thought about it and found I drove the car to sedat, the gearbox gets used to this. Then I kicked the car up to 6500 revs fora while and it flies again.
 

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Have you absolutely ruled out clogged cats? I know you said the tech has run a full diag but has he reset all of the adapations for the maf and trans post swapping in your new MAF? the fuel trims might be out of whack. It really is an odd problem you're having. Also, don't want to sound like an a-hole but you're sure the MAF is installed in the proper direction? With the airflow arrow pointing into the TB?
 

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Discussion Starter #13
I really have no idea what the tech did but everytime after I took out the MAF I will disconnect my battery for at least an hour b4 reconnecting it. Would it help clear all the codes or I still need to clear it with the tool? I think the MAF is the right direction coz it kind of have a different shape on both side when unscrewing it off the round duct housing so I just screw it back in like how I take it off.....but I really donno the problem now I havent replace my O2 sensor yet but I will do it soon and update it.....btw are the universal O2 sensors difficult to replace because the price difference is a lot =D
 

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w210 wwhhyyyyy

hey names andrew, i have same symtoms as you. my maf was bad... i replaced wit with an ebay sh*t. car was still runnin bad throwing p0100. so i bought the autohausaz.com bosch. cel light went off and after a day of driving car felt like it was adjusting itslef all day. 3 days later im driving it and no jerkin or falling on its face, but the issue of it not picking up and moving like it used to. it just climbs rpms very slowly like at the point of almost bursting in power, but holding back like crazy. before i had the bad maf if i had the gas peddle half way it was like the car was playin games wit me... is it goona go or fall on its face... but if i floored it, it would definitly go FAST. now i ggot the "right" maf no power just a lot of noise...?? after the o2's did your problem continue? does anyone have any more input for this thread?? i also replaced my cats wit generic magnaflows. that was during the ebay sh*t which still ripped when i got on it all the way. didnt try removing the cel light. it turned off automaticaly after a day. didnt disconnect battery. mabye ill try to disconnect the battery for 30 minutes to see if it "could" have power. if it "could" have power from doing that, nothing could be cloged because its capable of movin the air. its only when the computer/sensors is tellin the car to hold back, it does... tricky sh*t
 

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im having the same problems
replacing MAF helped a little but car is still slow 7.3 0-60 15.3 1/4 mi thats like 100hp off where it should be.
If you guys had this issue resolved please provide some input
thanks
 

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Discussion Starter #16 (Edited)
im having the same problems
replacing MAF helped a little but car is still slow 7.3 0-60 15.3 1/4 mi thats like 100hp off where it should be.
If you guys had this issue resolved please provide some input
thanks
did you disconnect your battery for 30 min after replacing the sensor? It will make a lot of difference (at least on my car), but it will be good for like 2 weeks or so you can do like 0-60 in +/- 5 secs, after 2 weeks you can do 0-60 in like 6 seconds and in like month and a half it will become 7 secs again,I guess if you floor your car at every stoplight then is different....then it will adapt it like that, or else it will be like grandpa after a few weeks again.....I really donno how to avoid the car not to back to grandpa mode.......so now whenever I have time I plug in the carsoft 7.4 and erase the adaption (kick grandpa out for a while) is easier then disconnect battery lol......is very annoying that adaption feature seems to be the part that play the games when you drive calm for a while it will think grandpa is driving but then sometimes when you need the instant power then grandpa is in the way....
 

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did you disconnect your battery for 30 min after replacing the sensor? It will make a lot of difference (at least on my car), but it will be good for like 2 weeks or so you can do like 0-60 in +/- 5 secs, after 2 weeks you can do 0-60 in like 6 seconds and in like month and a half it will become 7 secs again,I guess if you floor your car at every stoplight then is different....then it will adapt it like that, or else it will be like grandpa after a few weeks again.....I really donno how to avoid the car not to back to grandpa mode.......so now whenever I have time I plug in the carsoft 7.4 and erase the adaption (kick grandpa out for a while) is easier then disconnect battery lol......is very annoying that adaption feature seems to be the part that play the games when you drive calm for a while it will think grandpa is driving but then sometimes when you need the instant power then grandpa is in the way....
yep i did it today
NIGHT AND DAY DIFFERENCE my e55 feels slow 7.5 0-60 no faster what the heck? - MBWorld.org Forums
thanks
 

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I though I would post an update:
after replacing 02 sensors , spark plugs and wires, maf 2 times, MONTHs LATER I HAVE NO SOLUTION TO LOSS OF POWER .
After driving for a week after the reset car becomes slow again, not noticeable with grandpa driving mode but when I step on it a bit its very noticeable.

Im working with a good mechanic and so far we are leaning towards a problem with the ecu itself, possible problem with a programming. What actually is happening is that a car leans itself out at an Open loop mode to about -15% fuel correction. So thats why only during spirited driving the loss of power is noticeable and not during slow driving.
 

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You know instead of your "mechanic" throwing all these parts at your car why don't you drive it down to a MB dealer and let a "technician" figure out whats really wrong with it.
 

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You know instead of your "mechanic" throwing all these parts at your car why don't you drive it down to a MB dealer and let a "technician" figure out whats really wrong with it.
hahaha good one !

The first thing I did was take it to MErcedes dealership and they could not find jack wrong with the car, they just gave me a list with suggestions: change maf, fuel filter, spark plug wires.
I went back to them later one more time just for them to tell me that if no check engine light on they cant find nothing.
I took it to mechanic after changing MAF, plugs/wires, o2 sensors by myself, i guess this guys is like the only certified Bosch technician in our state. Our dumb Mercedes dealership send all vehicles that they cant figure out to this guy so I sure hope he knows what he is doing.
 
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