crousti

Hey guys !

I bought a 2003 clk 320 (w209) not so long ago, and i didn't know about how to detect a failing gearbox ... and now i think i can

it had around 135.000km ( 80.000 miles ? ) when i bought it. It didn't work perfectly, had a couple hiccups once or twice during the trip back when changing gears (bought it 700km away), and i noticed the dreaded rumble strip noise only when i was sure the road was in good condition ...

So once home i had a specialist do a GB oil change (it never had one) . It didn't fix anything, the guy told me it was "good", nothing special in the pan.

Now the car is making a whirring noise, stutters sometimes when changing gears, sometimes has trouble changing gears. When hot, the engine nearly does not pull the car if i don't accelerate (while it will pull well when cold - but this may be normal, i am new to AT)

And i noticed something about the rumbling noise: it happens after some time is spent NOT releasing the gas pedal. It sound like my fuel pump on my s13, when its sock & filter was clogged (which ultimately killed it). If i release the gas pedal and reapply it, the rumbling noise starts like half a second after. If i release the gas pedal and dont apply it for a few seconds (like you'd do when leaving motorway), it will make the rumble noise again, but after a few seconds. So i was thinking it could be a pressure release valve stuck closed somewhere, draining the pan... but this would have left metal shavings in the pan i guess. So i am a bit out of ideas...

I feel like the whirring noise is a separate problem (but a problem to address to ...)

Can anyone shed some light on this ?

Ultimately, if i have to change the whole GB, i was wondering wether installing a 722.9 would be worth doing (if doable).



Finally, last question. I know how to make an ECU tune, i did it on my s13. I would very much like to change the tune on the 320 so it can run e85 properly (it requires a timing change, no just AFR changes, and no flexfuel box does that).
But i have absolutely no idea what tools i'd need for that. Is there a standard OBD2 tool that i can use ?

Thanks a lot

insame1

Man you need to do some serious searching/research about MB.

1. are there any codes? you need to have it scanned by someone with STAR.

2. a 722.9 wont work. Well... it will but it wont be worth the money you would spend getting it to work.

3. Tuning a MB is not as easy as other cars and MB suggest not running any more that 10% ethanol mix and even that is not good for the rubber bits.

It is not easy or cheap to mod a MB and if you want to I would start with something a little hotter to begin with. Anything kompressor is going to be your best bang for the buck on mods.

crousti

0 - I have read this forum and others, and i have not found answers to my questions, thus i post them. I am well aware of the radiator problem and fluids mixing; i have seen reference to the whirring problem too, but i never read anything about the "delay" before it starts making the rumbling noise.

1 - I already got codes read. Nothing comes up.

2 - If you are going to tell me that it is not worth the cost, then by all means tell me where that cost is from. A second hand 722.9 is nearly the same price as a 722.6, so my question is about what is needed to do it. Is it a bolt on affair ? Do i need to get the welder out and contact a machine shop ? Do i need to create a new control software & hardware ? Do i need to hammer the body so it fits ? Do you have an answer to any of these questions or are you just answering what your guts tell you ?

3- I believe i said i built a race car and tuned it myself already. I have been running e85 fuel in an "incompatible engine" named CA18DET. The internet says that engine is made of glass and will break as soon as it reaches 300hp. I rape the car every time i use it on track, and the engine now has 160.000miles on it. Friend of mine did the same, although with a different budget and dedication ... he reached 700HP+ recently. Hasn't done a rebuild in the last 40.000 miles. 37psi of boost (stock is 8) , redline at 8800rpm. That thing is actually tough as nail.

Anyway I would not buy a CLK if i wanted another fast car. This is my daily. You don't understand what i want to do and are mistaking tuning the ECU and getting more power. I only want to set up the engine with the correct parameters so that i can run e85 correctly. I only need to be able to set timing and fueling since it burns slower and needs more fuel per gram of air. I am not going to try getting more power from an NA cruiser engine installed in a heavy car, that is nonsense.

Also, I don't care about what MB says about ethanol mix, this is just legal mumbo jumbo to cover their ***. Ever wondered why they talk about 10%, and not less ? Simple. You already have 10% mix in most regular gas, as per regulations (at least in Europe).
MB does not use any kind of special voodoo or unobtainium metal to make their engine, gaskets and lines, so let me worry about that. I have been running e85 in various engines now for many years, while MB has no interest in it and thus has made no research in it.

And again, my question is not "should i?" or "what values should i put?" but "how can I actually get the tables out, modify them and inject them back in ?". I have wideband AFR sensors and EGT probes already. If you have an answer to that, i'll be glad to read it. Just don't answer telling i won't get any power from it. I already know that, and it is not the point.

tw2

You can use an OBD2 to usb cable, read the ecu, alter it and re-write. Eurocharged does this. It is coded by VIN so you can only alter it not copy someone else's tune.

722.9 cost is in the electronic gremlins, having the tcu coded to your car etc. After that you have a second hand transmission that could fail anytime. Rebuild your 722.6 and you will have a reliable transmission for another 100,000 km.

gixxerboy

your trans is on the way out, there isnt going to be a fix for it, noises are always hard to diagnose but typically the pump or converter makes those noises.

switching to a 722.9 as stated would not be worth the headache, the tcm is in the trans in a 722.9 and external on a 722.6, changing the harness trying the get the computers to communicate properly plus all the other electronics that interact and are different its not worth it.

DanielFD

+1 on gixxerboy.

Really not compatible.. as stated sounds like the converter is on the way out. I had the same thing happen with my car and i changed my whole trans to get rid of it and it didn't go away. I eventually found a used TCU and that fixed my problem. Though i'm pretty sure my case was a rare case.

Rudeney

Did you get codes pulled from the TCU with SDS? Pulling codes with a generic OBDII scanner won't read MBZ's specific TCU codes. Also, check the radiator - if you have the Valeo, you need it replaced as it will keep mixing transmission fluid and coolant which can eventually damage the transmission (if it hasn't already):

http://forums.mercedesclub.org.uk/sh...42&postcount=3

Once the radiator is replaced, I'd do a pan-drop fluid and filter change:

http://benzbits.com/722_6/FluidFilterChange.pdf

Then follow it with a full flush:

http://benzbits.com/722_6/TransmissionFlush.pdf

Also check the TCU for fluid intrusion. It's located under the carpet and insulation in the front passenger footwell. The pilot bushing on the transmission electrical connector is known to fail and leak, and fluid can be "wicked" into the TCU. If this happens, some people have reported being able to thoroughly clean out the TCU as a repair, other have had to replace it.

After all of this, I would THEN clear and TCU codes and drive to see what happens. One other common problem is a bad conductor plate, but that has specific TCU codes (usually speed sensor errors) to indicate its failure.

DanielFD

I didn't have oil in my TCU or oil in the connector. Not saying Rodney is wrong, actually hes very right, but my car had a really special case. Just worth thinking about before paying for a trans like i did, as i got a used TCU for 40$ and had already replaced the trans for 600$..

Rudeney

There are many things that could cause these problems, and it's nearly impossible to diagnose "over The Internet". My thoughts are to always go with the "low hanging fruit" - rule out the obvious/inexpensive stuff first. Also, proper diagnosis by pulling codes with a tool than can talk to the TCU is imperative. Rumbling noises are most always going to be a bad torque converter and not the result of TCU or other problems. The problem is, there are no codes for that problem, but the good news is that you can get a rebuilt TC for around $300, and then it's just the labor cost to drop the transmission and replace it. Slips and rough shifts can be caused by low fluid levels.