Craigo

No it's not the supercharger "clutch"... No it's not a vacuum leak, and it's def not the actual gas pedal or throttle body. What could it be, bad fuel pump? You can go through the whole rpm range on light throttle, but the second you try to hit the gas pedal as the car was meant to be it just bucks and hesitates and doesn't do anything.... Anyone have some input for this situation at hand.

I also don't think it's the transmission... Thanks in advance guys.

grantwoodtx

Did you try a TCU reset? You may also need to have someone reset the adaptions using STAR Diag.

Roverron

What mods do you have if any?

X2Board

That is how my current issue started a few months ago, and I thought it was a bad tank of gas. Then the ESP malfunction related to the TB actuator last week. I think they are both related. Do you have a sprint booster by any chance?

Yuille36

Fortunately for E63 owners we don't have that problem, sorry that I can't help you.

stevebez

belt slip? But tranny is a good starting point.... does it do it with ESP off?

Yacht Master

You can guess all day long, go get a scaner and get the codes....

Yacht Master

Guess you never read any of the posts from Buckeyewalt, have you.

https://mbworld.org/forums/w211-amg/...esitation.html

AWOL

I had somewhat similar problems and the dealer said it was a slight misfire. They didnt fix anything, but when I got it back, everything was fine. Make sure all the plug wires are tight, and if they are, maybe swap the sparkplugs? Thats what they recommended before trying coil packs.

Jakpro1

How do you know that bro? Pedal Sensors go bad all the time. Our pedals are really just pretend pedals and are actually sensors that feed info to the computer for throttle/brake by wire.

Worth a try to do Sneaky ECU reset...which is TCU reset.

Also worth it to try battery disconnect for half hour and then reconnect and DONT FORGET to resync ESP (start car and while in park, turn steering wheel end to end a couple times each way. Otherwise you will get ESP Check Engine Light) Search for resync process on windows and sunroof as well.

Otherwise, pull those codes. Could be a million things going on in these sensor packed cars.

Craigo

I have used SDS. No codes, No Cels. I'm thinking it's a bad fuel filter/sender unit. No belt slippage. ESP on/off no difference. Hmm...

grantwoodtx

If you have SDS why haven't you reset the transmission and engine adaptions to see if it goes away?

Craigo

We did, nothing happened.

03'55AMG

can you hear/feel the s/c engaging?

Yacht Master

Odd no codes, so rule out misfires fuel & spark, sounding like the TCU (torque limiter) /transmission.

Do you have the tool to check your trans level?

bce63

I had that under heavy acceleration, as soon as car got up in RPMs, car just started bucking until I let off the gas. My two fuel pumps were replaced. they were dropping pressure at high rpm.

buckeyewalt

I did and still do have that hesitation,,BUT come to find out that what I feel is technically not a hesitation. It has been since diagnosed and a solution is to have the throttle mapped. All drive by wire cars can get it and some do,while others don't. Cory with Kleemann gave a great description of the problem and the best thing is that it can be fixed. Here is his description which is better said than I could...............

Because these cars are drive by wire, throttle opening VS. pedal position is not linear. The signal from the throttle pedal is viewed by the ECU as a torque request. If the pedal is pushed to say 50% very quickly, the ECU sees this as the driver demanding XXX amount of torque very quickly, so the ECU might open the throttle 80% very quickly to fulfill it's calculated torque request based on the drivers input. If the pedal is pushed to 50% very slowly, the ECU may only open the throttle valve 35% much more slowly. Re-mapping throttle response tables will help make throttle valve opening Vs. Pedal position more linear (but not a 1:1 ratio in both opening and speed like a cable operated throttle) and will also remove the "dead" spot at the beginning of pedal travel that all drive by wire MB cars inherently suffer from. Throttle mapping will not, however, remove the ECU's ability to adapt to a specific driving style. ME9.7 cars like your E63 seem to adapt to changes much faster compared to the old ME2.81 V8 Kompressor, but the ECU will still adapt to your driving style.

I don't know of any tuner able to completely disable the adaptive function of these ECU's. I've had discussions with KLEEMANN's programmers about this, and unfortunately, they've not been able to figure out how to disable it- why I don't know, but I suspect this feature is not controlled by the same EPROM that is programmed for ignition timing, fuel delivery, throttle mapping, load maps, etc. That's just my own guess though.

Craigo

This is more or less what we think is the issue. I believe today or tomorrow I will be running a test on the one sender it should pump a liter of fuel i believe in 28 seconds.

Hopefully just a clogged filter as I've never changed it EVER.

Craigo

I'll update this once I run a test on the fuel pumps/senders.

Craigo

Replaced both fuel pumps and sender unit and the issue went away. One of the harnesses to one of the fuel pumps was completely corroded and barely making a connection.

Rust bucket

Great info my car just started doing exactly this Saturday.

Yacht Master

Good job, interesting that you did not have any misfire codes, how much did you have to pay for the pumps / tank units?

Rust bucket

I dont have any either.

Craigo

We were able to narrow it down to that because of the lack of codes... We hooked up a pressure gauge to the fuel line. At idle it held 40Psi, once you hit the throttle it dropped to 10Psi, that was the dead give away it was the fuel pumps/sender unit. Walked out the door with all OEM parts from our local dealer for about $899.

Craigo

Here are the two part numbers for the fuel pumps/sender found in our gas tanks under the rear seat located on both passenger and driver side.

211 470 51 94
211 470 17 94