Three years ago, when I had about 3000 miles on my 2004 E55, I took it to the track several times. It would ALWAYS run 12.6-12.7 @ 111 - 113 mph with about 1/4 tank of gas.

Now, my E55 has 40,000 miles on it, but other than that, it is the same....no mods, still bone stock. The last 3 times I've taken it to the track, I could NOT break into the 12s. The best run yesterday was 13.03 @ 107.2 MPH. It also ran 13.38 @ 106 mph several times last night. I had about 1/8th tank of gas last night also.

The Density Altitude was even lower yesterday than it was when I ran three years ago. I even had a BETTER 60 Ft time yesterday (1.99 seconds) than I had three years ago (2.1 seconds.)

What could be causing the horrible decrease in performance? I'm not getting any error messages or anything, and I've taken it in for all scheduled services.

I used to be able to walk away from my friends automatic Camaro Z28. Last night, we ran dead even. (well, we both ran 13.38 seconds, but I was at 106 MPH, he was at 104 MPH) (He hasn't modded his car either.)

This is starting to make me mad.......does the E55 lose performance this much as the miles build up?

 

??intercooler pump failure - no codes, hard to diagnose.

 

Have you tried the "sneaky reset" with the gas pedal?
Maybe the engine is pulling timing if it's dirty like Finny showed us?
Have you had a tune up?

 

I have no idea what a sneaky reset with the gas pedal is. Can you explain it? Never had a tune up. A "tune up"? Are you referring to the scheduled maintainences? If so, I have had the scheduled maintainences done.

 

Check this link for "sneaky":
https://mbworld.org/forums/w211-amg/148019-holy-crap-you-guys-sneaky-ecu-reset-works.html

I had my plugs changed at 25,000 miles. I don't trust MB service schedule when I beat on the car.

 

let me guess...you probably haven't been around the board in over a year. you need to search the secondary air pump recall and ecu reflash threads. that will probably answer all of your questions and make you VERY upset all at the same time!

 

Read the ECU reflash threads.........which really are a bunch of seat of the pants "feel like I'm going faster, but really not going faster" threads. I seriously doubt that an ECU reset is going to make ANY difference in 1/4 mile times.

What is the secondary air pump recall?

 

i was talking about the ecu REFLASH...not the ecu RESET which only resets the transmission's adaptive shift points. the ecu reflash associated with the secondary air injection pump recall somehow detuned MANY e55's, mostly '03 and '04 models. it has been documented on the dyno to have detuned cars by 40-70hp and drop cars from mid 12's to low 13's at the track. there's hours of reading on this so a search is in order.

if this is the case, mb won't admit to anything and dealers have no way to fix it so the only sure way to return your car to normal is to pay powerchip to flash your ecu.

many people noticed this right away, but i'm sure there are much more that are still driving around in what's essentially now an e500 with e55 badges. keep your 1/4mile records, go get a dyno run to document the power loss, and take it to your dealer.

another possibility is that you could be experiencing an intermittant intercooler pump failure but typically you'll get a supercharger shut down which cuts almost all power and is REALLY noticable. regardless, lets hope this is the case! either way, let the dealer know your car is significantly down on power and let them investigate.

 

Good pointsand call chiromikey, I just assumed all that was checked out. I have K2 and lost about 65 rwhp to the reflash. I think if the pump was failing the 1/4s would be much worse than what is being experienced.

 

From the time and trap he has lost 67 HP. sounds familiar.
dsc, I agree if it was the pump, the S/C would disengage.

 

That's why you don't bring your car to your dealer for service, for my modded toys at least. I always get a copy of maintenence schedule of what needs to be done and do them myself.

 

For us 03 and 04ers, It sure is nice to use that free maintenance to 50,000 miles!

 

Well, I called the Mercedes dealer that I always use for maintainence. They said that they have no record of ever having reflashed the ECU in my car.

Now I *really* don't know why I'm losing power...............

 

Here are a few things to try:

1) If you or a friend have Autotap, do a data log.. If your intercooler pump is on its way out, it may have intermitent problems and not be running properly.

2) Take a piece of chalk and mark across the S/C drive belt onto the snout of the S/C.. Go and take it for a hard run.. If you come back and the chalk line has moved, you are having belt slip issues.

3) Inspect the S/C belt and make sure there is no black dust, no wear and no frizzing.. Inspect the underside of the belt and make sure all 7 grooves are full and there are no broken or worn sections. Depending on the miles, you might want to put a brand new belt on there. Sometimes just the belt being on for too long causes it to stretch or wear and will not provide the proper contact. Spend $40 and get a brand new Gates belt.

4) Check the spring tension on your tensioner. Try and wiggle it up and down with your hand.. If you can do this, then there is a problem. There should be no play in the tensioner.

5) Get the dealer to check your spark plugs.. its a long shot, but you never know..

The autotap logs will reveal the true symptoms of your car and then we'll be able to offer some more advice.. If you dont have it, my recommendation is invest the $250 and get one.. its an invaluable tool.

Good luck!

 

Thanks!! Where can I get an Autotap?

 

http://www.autotap.com/

 

OK, I'll order the Autotap. I won't know ANYTHING about the information it gives me though.........I assume you'll know something about the information if I post it and maybe can help me further?

 

You may want to swing by your dealer and get a copy of all the work that has been preformed on your car, or look through all your receipts. Look for "secondary air injection pump and relay" that seems to be the recall for the flash.

 

follow vrus' advice.

i've beat this to death (only because i know the effects all too clear)...however, i can promise you that if you have had all your scheduled maintenance performed by the dealer (as you stated), then you have without a doubt had your ecu reflashed during the secondary air injection pump campaign.

call back and don't ask them if they've reflashed your ecu, ask them if they've performed the secondary air injection pump recall...or simply look at your records for it.

 

+1

 

OK, I called the dealership back and asked them if they ever did the secondary air injection pump recall. They said that they DID do that service on my car in April 2006 and that the ECU *WAS* reprogrammed.

I think we may have figured out the problem!! He is going to pick up my car tonight and take it in to check it out. He said that he CAN reflash the ECU back to the way it was for me. We'll see what happens tomorrow..........

 

I personally think the secondary air injection pump reflash has nothing to do with power loss. I had mine done and the car feels as strong as ever, and even my trap speed has increased a bit (116-117 vs 115 before the reflash).

 

I doubt he can reprogram it back but if he is willing to do that, more power to ya! Hope it works out or look to spend 1k for the ECU flash my kleeman or powerchip...

 

Well, that sure is a hell of a lot better than my 106 mph trap speed. Sucks to go from 113 mph consistently to 106 mph consistently.

 

Your one of the lucky ones... its not a myth... there has been MANY MANY accounts of power loss including my E55. I couldn't even let the tires loose in M mode with ESP off.... it was pathetic!