C43 hitting rev limiter?

[e harmon]

Hello folks,

I'm still getting acquainted with my new baby (1999 C43) and have some questions. I noticed that when I'm at WOT and hit redline, the revs sharply stop climbing and drop a few hundred RPM. It reminds me of hitting a rev limiter, but that didn't make sense to me in a high end automatic car left in "D."

I searched and found this thread:

mis-u-jerr's post from Feb 2004 (www.club202.com/forums/showthread.php?s=&threadid=3133&highlight=c43+transmission)

(btw mis-u-jer, I hope everything worked out)

Is this a common problem, with hopefully a common fix?

Also, I may have a problem with the MAS as well, according to mis-u-jer's description. Does this stand for Mass Air Sensor? Sometimes my car is a monster and sometimes it is much less. Would this be a good thing to check, and if so, is there a good way to demonstrate a faulty unit for warranty coverage?

Thanks all,

e harmon

[tinter101]

Hey, how fast were you going when you were limited?
I won't tell anyone I promise.

[Denlasoul]

I've read that the C43 is limited to 155mph. I've heard that figure can vary, mainly that the limit is a little bit higher.

[e harmon]

I was hitting the rev limiter, not the speed limiter :) .

Regards,

e harmon

[jnolte]

change your tranny fluid. ASAP unless you wanna pay big bucks for a overhaul

[e harmon]

Thanks. Am I understanding that this is a symptom of contamination in the fluid?

Regards,

e harmon

[jnolte]

Originally posted by e harmon
Thanks. Am I understanding that this is a symptom of contamination in the fluid?

Regards,

e harmon

it could be alot of things, but it starts with changing your fluid, then from there it can be other things.

even tho MB says its a "lifetime" matinence free trannny this is BS!

[e harmon]

Definitely sounds like something I should do. What' I find interesting is the car is just coming up on 40k miles, and appears to have been otherwise cared for.

I thought I read here, or elsewhere, that someone had a faulty transmission solenoid. Is this a likely culprit as well?

Also, I'm understanding this addresses bumping into the rev limiter. The car also sometimes appears to struggle when revving up while in gear, such that 3/4 throttle feels like 1/8 throttle, and the RPM takes forever to climb, though the engine does not appear to be "stumbling". (I don't mean the delay from the DBW throttle mapping either; the throttle is already open and the car is accelerating, just much slower than normal). When this happens, ESP is engaged but the light is not flashing. Is this part of the same problem, or could it be the MAS?

Do either of these conditions cause error codes or pending codes? I have not seen any CELs.

Finally, what would be the preferred fluid to run in the transmission, and where should I get it? I will be taking it to a Mercedes repair shop, but would like to provide the fluid myself.

Thanks again and regards,

e harmon

[jnenad16]

Originally posted by e harmon


Finally, what would be the preferred fluid to run in the transmission, and where should I get it? I will be taking it to a Mercedes repair shop, but would like to provide the fluid myself.


the fluid has to be MB OEM ATF. Its about $10 a quart, and you will need about 8 quarts. Also, if you want a performance fluid, contact Redline Oil, and ask them which of their ATF's is suitable for your application. It will most likely be their D4 ATF, thats what I'm running in my BMW 740i.

nenad

[SLAMMED_C]

even tho MB says its a "lifetime" matinence free trannny this is BS!
its not BS, it is true.. its a lifetime fluid. no need to replace. trust me, I thought it was a load of.... too, but no need to replace.


noticed that when I'm at WOT and hit redline, the revs sharply stop climbing and drop a few hundred RPM
I notice this on my car too on occassion, pedal to the floor and it will sometimes hit the rev limiter and take a sec or so to finally shift. dont forget that the transmissions in the newer cars are electronic.. and they also adapt to ur driving style.. so if you just putter around.. but then decide to open it up, it may decide to act up on you.. while it re-adapts to the new driving style!
it may also be a problem with the transmission control module.. take it in if you have warranty.. see what they can do.


Do either of these conditions cause error codes or pending codes? I have not seen any CELs.
A MAS problem will not always set off a code.. take it in for warrany if you have still.. just tell them it feels like there is a loss of power intermittantly... they will look into it for you.

[C43]

I was having the same problem. I S/Cered my C43 and I have gone through 3 MAS's. My mechanic was cutting them to fit between the S/C. This last time my car was bogging out around 2000rpm. My car was shifting when it wanted to. When doing 100mph and slamming on it the car would down shift to low, or just rev freely until limited. I bought yet another MAS. I decided to trim the rubber connector to the MAS and throttle body instead of cutting the MAS. Strange setup with S/C. I still can not find a air cleaner small enough to fit with the HPS GEN 1
S/C. Anyway my car is back, it is brand new. Now she is shifting perfect, no bogging, no more hitting the limiter. All of her power is back, drove home today between 2nd and 3rd gear the whole time, This is a great car. Change your MAS.

[alboogiee]

i just encountered the same thing on my 99c230k... i washed it, and after i was done, started and reved the engine to push the water out of the exhaust... well i tried to redline it, but stopped roughly at 4, 4500 rpms...

on a side not i can vouch that there is no limiter (on rpms) while driving, i was doing 90... and accedently downshifted to 3rd, well its like grand torismo when playing manual mode, the car will just rev at the redline until the cars speed catches up with the rps...

[e harmon]

Originally posted by alboogiee

on a side not i can vouch that there is no limiter (on rpms) while driving, i was doing 90... and accedently downshifted to 3rd, well its like grand torismo when playing manual mode, the car will just rev at the redline until the cars speed catches up with the rps...

If the car stayed at redline even though the gearing would have taken it higher at your current speed and gear, doesn't that mean some type of limiter was in play? Unless, of course, your tach was pinned and the engine was spinning so fast it was off the scale. If so, that's pretty badass. :D (I wouldn't wish that on your car or anyone else's, but nice to know if it could handle it and keep going.)

If there was intervention in your case, it sounds like it was "softer" than what I experienced, which was a distinct "bounce back" of a few hundred RPM.

Incidentally, I haven't noticed the problem for a few weeks now, but already made an appointment for fluid and filter change.

Thanks

e harmon

[alboogiee]

Originally posted by e harmon
Unless, of course, your tach was pinned and the engine was spinning so fast it was off the scale. If so, that's pretty badass. :D (I wouldn't wish that on your car or anyone else's, but nice to know if it could handle it and keep going.)


exactly what happened... except the tacho needle was jumping as if it were limiting, the car couldnt do 90/5ish in 3rd so the engine tried to slow the car speed down by pining the the needle.. my asumption

[C43]

I thought it was better. Today on the highway doing 60 I punched it, she downshifted perfect and the car took off racing towards 6000 rpm. I was in my glory until she decided not to shift and just stay pinned at 6000rpms until I blipped the gas and then she upshifted. I remember the same scenario when she was perfect and the upshift at high speeds was like heroin, how it would just slide into 5th gear and rocket towards 155mph. What can I do? I changed the MAS and I change the trans fluid. Maybe I should try the selliniod(spelling)? What other sensors should I check.

[jnolte]

Originally posted by C43
I thought it was better. Today on the highway doing 60 I punched it, she downshifted perfect and the car took off racing towards 6000 rpm. I was in my glory until she decided not to shift and just stay pinned at 6000rpms until I blipped the gas and then she upshifted. I remember the same scenario when she was perfect and the upshift at high speeds was like heroin, how it would just slide into 5th gear and rocket towards 155mph. What can I do? I changed the MAS and I change the trans fluid. Maybe I should try the selliniod(spelling)? What other sensors should I check.

perhaps you could get your tranny reporgrammed to shift less not so aggresive?

[98c43amg]

Originally posted by e harmon
Sometimes my car is a monster and sometimes it is much less.

I just came upon this thread. I know this is from Dec 2004, but I will add one thing that's plagued me as long as I've owned my C43 ... that is, I =hate= MB's "adaptation" program in the transmission ECU ... deep hatred! If you're not on the car all the time, it basically goes to sleep -- grandpa mode I call it. I =hate= it!
:mad:
Answer to that is to row the shifter. My tranni is in either second or third most of the time around town.

[alboogiee]

Originally posted by 98c43amg
I just came upon this thread. I know this is from Dec 2004, but I will add one thing that's plagued me as long as I've owned my C43 ... that is, I =hate= MB's "adaptation" program in the transmission ECU ... deep hatred! If you're not on the car all the time, it basically goes to sleep -- grandpa mode I call it. I =hate= it!
:mad:
Answer to that is to row the shifter. My tranni is in either second or third most of the time around town.


:werd:

[C43]

My dealer acted like I was crazy when I asked for my ECU to be reflashed. Where can aftermarket programs be found for the trans? Could it be O2 sensors? I wish I could make it manual.

[JA5ON]

I just experienced this today, I dont drive my car much and when i do its to work bout 3 miles away and I usually never get over 40mph, today I decided to get on it alitle on a back road and it hit 4k and didnt seem to have any power, almost like the trans was slipping, if I slowly accelerate its fine but if I went to punch it, its a dog, whats the fix ?