2000 E55 bought in San Diego in 2005 with 48K. Ran like a champ for 20K with no issues. Great power, scary acceleration, burnt through 2 rear tires etc. I move to New England ( yes it sucks here!) and things start to go bad fast. First the CEL for "EGR Flow Malfunction". Replaced the EGR valve and tube. After replacement the head tech claims "it's the fastest 210 E55 we've ever driven". I have a friend who is the service manager at a MB dealer and I have been in the dealer parts business for 30 years so I have an advantage and know the tech has access to all of MB's best diagnostic equipment and is very knowledgeable. They give the car a clean bill of health and send me on my way. Later that week the CEL blinks again...."Misfire 305,P306,P307" car runs slow as ever. I replaced the spark plugs and the wires. No joy. Diagnosed as needing drivers side catalytic converter. I am out of warranty (8years/80K) by 2 months. My buddy pushes it through under "Goodwill". That saved me $2500. Car runs like a bear for about 2 weeks. Today I decide to try a 0~60 run and time it with my stop watch. I come up with a best of 6.94. I had my wife run the watch and her best was 6.78. I've driven E430's and that is about what it feels like. This car used to spin the tires if you hammered it on at 20mph roll. Now it will barely spin the tires with the ESP shut off from a standing start!
I bought a new mass air flow sensor for it on speculation that I would have to replace it eventually and swapped it in today with no difference what so ever.
So, is it the passenger side catalytic converter? No rattle or knock...
I replaced the air filters 10K ago. What's left? Fuel filter? I've ran 3 tanks of 93 octane through it as well.
I'm ready to bail on this one much as I liked it when it ran great.

 

That sucks man! I just moved down here from Maine myself. These cars aren't made for up there...I will tell you that...rear wheel drive in snow, pot holes in the roads....need I say more.

I don't think I can pin point anything from where I'm at, but when mine misfired I had to replace two ignition coils. Though I'm not sure, this would do anything for you?

Keep us updated on your findings, and don't give up on it yet. And good luck up in New England, and watch out for those Damn Yankees on the highway. (I used to be one of them )

 

Sucks to hear your situation, I'm in a similar one. Took mine to the track a few weeks ago and it only went 14.58 @ 98mph, and has been slowing down more scince. Got the missfire codes the other night too but for the right bank(P0300, 301, 302, 303, 304)and it wasnt missfiring. The missfire monitor in the ECU doesnt actually know if your missfiring or not but looks for crankshaft speed variation to determine a miss. If the cat on one side os clogged more than the other it shows a power loss on that bank, which slows the crank down when a cylinder on that bank is firing and can show up as a missfire. I'm convinced I've got a bad cat on the passenger side(pressure tested it and showed 1psi at idle and 6psi on snap accel test)and am bringing it in Monday to hopefully replace both cats while it's still under warranty(till 3/28/08).

I'm surprised they only replaced the one cat though, where I work the only time we'll replace one side only is when it's due to physical damage like being hit or cracked/leaking. Anytime it's a performance or driveability issue with a bad cat we replace them both. I'm not saying it's definatly the cat but we wouldnt have taken a chance just replacing one.

 

A Bad catalytic converter will cause a misfire code and as a result your car will be driving in limp mode to protect the motor. This is also why you guys have no power.

 

before you spend money on a new cat,
do this
mark your #5,6,7 ignition coils so you know where they were, then switch them around with some of the other ones, while you do this of course reset the codes, and see what codes you get, obviously you might just be able to track down some bad coils (if original ones in there i wouldn't be suprised) specially since new spark/wires in already.

the other thing to consider is oxygen sensors, i've had it happen to me in the past on a different MB, when an oxygen sensor was on the way out (but not fully out as in to give any codes) but yet it sure did give me same codes with misfire, once oxygen sensor replaced back to like brand new running.

don't give up on it, i don't think it's the cat from what you've described

 

I am surprised and worried about my own '99 E55....because I read a lot about trouble with owner's catalytic convertors and various sensors!

Is it my imagination or do these V8 cars burn through them prematurely or what? I have never heard of any other performance car that needed cats with the low mileage frequency that some of your guys' cars have?

It all has me quite worried about my own vehicle....I've had terrific luck with it for a year now...but I can not afford to dump a lot of cash into repairing those expensive items if/when they fail! And according to everything I keep reading about....they seem to fail often!

 

Thanks for all the reply guys. I appreciate all the feedback.

It's just weird how the car can be "full on" then gradually slip into 3/4 power without throwing a code. My tech resets the ECU to factory parameters after every visit and that's when the car performs as it should.

The only thing I did from the time I left San Diego was to install four 245/40-18 Dunlop snow tires on the stock rims. That wouldn't screw up the ESP computer or anything else, would it?

TTA850, I was wondering about that myself. If one cat is bad it stands to reason the other could be on it's way out too. Hopefully my friend at the dealership can push through another one under goodwill if that is indeed the problem. How expensive is a back pressure tester?

Eurosport, We hooked the car up to the factory diagnostic and you could see all the values for the oxygen sensors were spot on. Same with the MAF sensor. Driveability issues are always the toughest to diagnose. Often times it will be something obscure or bizarre like a bad ground or poor connection. I'll give it a little more time and $ but it really stinks driving a car that feels like it's only giving 60% of what its got.

ProjectC55, No CEL or codes after a scan. No misfire that I can detect either. We'll have to see what my dealer says.

xlr8tin, You said it brother! My car lost it's California cherry in a big way! I seems to be saying "FU" for bringing me to this God forsaken frozen salty sandy wet depressing area! I lived here for 40 years and moved to San Diego in 2004. I loved it (besides the wildfires last year, scarey) but moved back for family considerations. But as I tell my wife almost every day "I'll be back" as Arnold would say!

 

I borrowed the tester from a coworker, it's a Bluepoint back pressure tester available from any Snap-On dealer which means it probrobly carries a higher price than most but I dont belive it was that expensive. Hopefully they will take care of you if it is a cat, I'm bringing mine in tomorrow morning so I hope to have an answer soon.

 

Your e55s should be running under 5sec 0-60 and low 13s in the 1/4. My stock 95 c36 with almost 100k miles runs mid 5sec 0-60 and 14sec @99 in the 1/4.

 

I will put my $$ on it that you have a bad cat!

The same exact thing just went on with my friend Joon(Amg_rider)'s E55. The dealer could not figure it out but he went to my friend who installed my 5.5L motor and right off the back he knew what it was. Joon has since fixed the car(bad cat was clogged) and it hauls ***.

Also ,just for maintenance reasons chg all the O2 ensors at once. That is what I did and a necessary maintenance thing to do to all of these cars.

 

since you guys are on here, what do you think about this issue (*cough* on a bimmer)

throws a "pre-cat too rich" code every couple weeks or so
MAF readings seem good
O2 sensors recently replaced
fuel filter recently replaced
reprogrammed DME per some stupid bulletin that thought it'd fix the problem

i'm guessing a small leak in the intake somewhere causing for the computer to compensate and run too rich at certain times?
time for smoke machine test?
thanks in advance

 

Yea, I was glad to leave. It's makes you appreciate other places more. I will say though that springs and summers are great. Fall can be pretty, but it can get brisk. Where are you right now?

P.S. the roads don't get any better come nice weather.

 

As previously stated....
I bought a new mass air flow sensor for it on speculation that I would have to replace it eventually and swapped it in today with no difference what so ever.

I was searching post yesterday on all the MB forums I could find for "low power" or "MAF" issues. As it turns out I never knew you had to disconnect the battery for a half an hour after installing a new MAF to "re-adapt" the ECU to the new values from the new MAF. Well I install my replacement MAF that previously did nothing, disconnect the battery and go to bed for the night. Today I hook up the battery and head out for the highway..... Long story short, it's back to AMG status! 0~60 in 5.22 and pulls like pro stock drag car. Thanks for all the suggestions and advice and once again the internet has saved me $$$$.

 

Great news Is you car stock?

 

Yes, totally stock. If I do any mods it would be a slight lowering and getting my wheels refinished to new condition.

 

Did you have any electrical issues after you disconnected the battery? No issues with the radio or other electrical sensors?

 

On the topic of Catalytic converters, is everyone using the dealer's? I'm guessing if the warrenty is still in effect, people will use the dealer, and cost isn't a concern. If you were to change it out of warrenty, what would be the best option. I always hear, and firmly believe, that a dealer cat, although pricy(sometimes twice as much as aftermarket), is built much better and will perform and last longer than any aftermarket one out there. Has anyone found this to be true? And by built better, I mean they use a higher quality converter material.

Is there anyone who has used an aftermarket cat, and is satisfied with it? Also, despite living in California, I would love to give the car more power. If my cat went bad it would be really temping to run something severly illegal. And then put some cheap cat in to pass emissions, and change it back out. I've been looking at a cross over pipe for the extra power/torque, but have always wondered what my options would be when the cats go bad.

 

I'm using Metal Cats high flow 200 cell cats. You can google the name and the company will come up.

 

I'm surprise it did not adjust right away. At least when I chgd out my bad one with my new one,the car adapted after qutie a few starts in no time.

 

I was surprised too. I was so disappointed when I installed the new MAF and it still ran like crap for an entire day. Then after the battery disconnect overnight it was like a Christmas morning miracle! Still running great.

 

Just the usual, enter radio code and recycle windows and the sunroof. The BAS and ABS fault codes will appear on the command display but they magically disappear after a few full lock turns and brake applications.

 

A new MAF shouldn't require a battery disconnect for the car to sync up with it. As soon as you start the car up, the new sensor will send in what it's reading, and the car's ECU should adapt pronto...

Almost sounds like you have cleared out all the "adaptive" stuff, and the car has gotten faster for it. Or, maybe you have cleared out the ECU's more recent history on running condition, which would have included the readings from the bad MAF sensor, leading the ECU to believe the car was running too lean. Richening the mixture = power loss. Now, the a/f map the computer selects based on the good MAF is one that provides more power...

I suspect one of those two, or probably a combination, to be the case.

In any event, you can clean your MAF sensor rather than replacing it, the next time you have this problem. CRC makes a spray-on MAF cleaner that you can buy for $6 at autozone, or you can use the old trick of rubbing alcohol and a q-tip (this actually works best).

 

I usually just recommend replacing the MAF. It's not a wallet breaker. Time and time again,cleaning it has only proved to be a temporary fix that gets worse and worse over time..

 

Well...on a 600 they run $582 apiece and there are two of them, one for each of the two intakes. So I guess I have a stronger motivation to clean them rather than replace them.

I am not sure how much they cost for an E55?