ML12NYC

Has anyone experienced inconsistent acceleration from a stopped position on the 4MATIC? I have a feeling this may somehow be related to the stalling issue.

jweezy

gas or diesel?

ML12NYC

4MATIC = Gas

jweezy

You sure?

ML12NYC

LoL...well the badge says 4MATIC not BLUETEC so I'm pretty sure.

AsianML

What do you mean by inconsistent?

ML12NYC

Sometimes I get immediate response and slight smooth boost and other times I get delays and a jolt. Both scenarios using the same amount of depression on the pedal. This is inconsistent since I'm using the same amount pressure on the pedal.

jweezy

Boost? Do you have a gas or a diesel?

jweezy

Wiki:

4Matic is the name of an AWD four-wheel drive system developed and used by Mercedes-Benz. It is designed to increase traction in slippery conditions.

dgiturbo

ML12NYC,
all 2012 ML's are 4Matic in the US. They can be gas or diesel. Yes, those I have seen that were diesel had the 4Matic badge replaced with the "Bluetec" badge from the factory.
As this is a new vehicle, swing by your dealer and after they fix it under warranty, let us know what they say caused it.
For what its worth, the ones I test drove were diesels, and they accelerated all 4 wheels just fine.

ML12NYC

Let me rephrase this for simplicity.
Scenario 1: I press the pedal and I get a nice smooth acceleration.
Scenario 2: I press the pedal (same amount of foot pressure) and get a delayed reaction and then a jolted acceleration. So I press the pedal and nothing happens for about 2 seconds and then a jerk of acceleration.

I think this is now clearly descriptive.

Thank you for the definition of 4MATIC. Common sense at this point. On this forum I have commonly seen the relationship between 4MATIC = GAS and BLUETEC = DIESEL especially since this is a forum for the “2012 ML”. But to please the people….I will make sure to be more specific and precise when commenting. I also have now changed my signature so everyone can see I’m driving the GAS version.

The truck is currently at the dealer for stalling problems (Look at other threads for more details). I am hoping there is a resolution that fixes both problems.

Thanks for replies (not being sarcastic).

jweezy

ML12NYC:

I was just joking around with you before, hand don't take it personal. I was being sarcastic, yet in a good way.

To your issue, what car did you have before? I ask because every vehicle reacts different when throttle is pushed, RPMs, TQ, HP, transmission and other factors such as throttle sensitivity and such...even when the throttle is increased some cars have a computer that monitors the enviornment conditions to medigate how much power is applied or just to make sure the car will accelerate safely.

What you are basically describing is correct, and nothing is wrong. It happens with all automatic vehicles, how you feel or notice the shifts in transmissions is based on the kind of transmission and setup of the vehicle. With a CVT (Continous Variable Transmission) there will be no shifts in acceleration or de-acceleration however the speed and "jolt" is non existent.

The MB ML350 has a transmission with 7-speeds most are at the lower speeds of 75. So what is happening is during your "scenerio 1" you are in 1st gear - a butt load of power is directed through the 1st speed (which is geared for starting from 0mph). And you speed and its actually very quick in the gas...I know its in the 6 sec range

In your "scenerio 2" - You are probably at "xx" mph, our computer and transmission is geared towards MPG - so when you are at a moving speed the computer and tranmission is attempting to switch to the highest possible gear (5-6-7 usually).

If you are at "xx" amount of speed, you press on the gas - the computer senses how much throttle is applied - it then relates that to the transmission - which puts you in the best possible gear to give "MAX" power. However, that shift is from lets say 6th gear all the way down to 2nd gear is the pause you are noticing. Which is perfectly normal. The tranmission is although going at tremendous speed of switching from 6 - 5 - 4 - 3 - to finally the 2nd gear will be a slight pause.

The other issue is RPM, you have gas and I believe applies most power around 4,000 - 6,000 RPM or something (not exact) The time it takes for the transmission to switch into the correct gear, and then allow the engine to apply the higher revs (revolutions) the engine will then apply power, causing that JOLT you speak of.

So to summerize - Engine shifts into correct gear -> Engine calculates -> RPMs rev higher -> Power applied. -> JOLT

If you want to test the issue - Put the car in manual mode (you have the ability to shift gears) -> switch to a gear that is the best gear for your speed -> Slam on the gas -> JOLT!

You completely take two steps out of the process giving you the ability to apply the most power when YOU want to.

There are a lot more steps which I skipped like traction control calculations and all this other MB tech. Remember, The M-Class is quite possibly the world's most advanced SUV

ML12NYC

Jweezy: It's all good...I didn't take it personal. I appreciate the help.

I'm guessing it is my driving habits since I'm use to driving my Infiniti G35 which is a sporty ride. Both scenarios are from 0 mph but from different driving characteristics. Scenario 1 is driving from highway to then red lights. Scenario 2 is red light to red light driving.

In the Infiniti I have never witnessed a delay. It is a rocket of immediate acceleration.

I guess I just need to get use to the truck. It's only been a week and a half.

Thanks again.

katiesdad7

Automatic transmissions have been around for as long as I've been alive. I think they got the bugs worked out of it. If the jerking is caused by the transmission then it needs to be repaired. Heck, even my 76 Camaro doesn't hunt for gears and the transmission is silky smooth. If it is the tranny then my guess is a software update is all it needs.

BTW, mine goes in tomorrow for the same reason and I have the diesel.

300DTurbo

The quote from earlier comes to mind, "Lexus is on the Cutting edge and well Merc is on the Bleeding edge."

Shifter

LOL, Lexus just copies what the Germans came out with 8 years ago!