M156 6.2l motors down on power
 

So apparently this is a bit of a thing that I'm hearing more and more about.

I've got two guys that email me randomly from the UK (via the local MB club) and I heard that four 6.2l cars at a dyno day this week (again in the UK) were down on power and pretty unresponsive to the eurocharged V5 tune (like 8hp gains or something like that)

The power loss seems to be anything from 40-60hp and it's from WOT at low rpm, all the way to fuel cut.

Speaking for my own car, the power loss on a graph looks like the entire plot from 2000rpm to 7000rpm has been shifted vertically downwards when overlaid against another 6.2l car. It's not as though the car makes good low-end/peak and then bad low-end/peak. It's almost as though the throttle isn't opening fully. However for my own car, I had the throttle bodies scanned via STAR and they appear to be opening fully.

From what I understand, a clogged PCV breather pipe can attribute to the issue and claw back power if replaced. In the case of my car, this didn't help.

I know that some members have had problems with their throttle bodies (mr747 with his supercharged 6.2l) and replacing one of them managed to get his power back.

Leaving this thread out here for future reference and to let other members share their findings to see if we can solve this issue as a community.

EDIT: For the happy ending to the story with it properly tuned on the dyno - please see:
https://mbworld.org/forums/c63-amg-w...yeah-baby.html

I'm coming from a modified 335i and I feel like this is slower to accelerate. It could just be the turbo feeling, but I've felt like it should be faster. I think I'll look into changing out the TB, depending on price.

Post your dyno graph.

I know this can happen due to not having oil catchcan, oil can get into the intake manifold, and gunk builds up in throttle bodies also leading to blockage of breather pipes....
A c63 who i use to drive with here had this issue but got it cleaned out.
Another friend of mine had this issue due to fuel pressure in his m156, not sure how he fixed it..

yes and no - theres guys whove taken off their manifold @ 100,000 miles and had 0 oil build up ..infact my manifold was placed twice and both times it had 0 build up ..if you DD in a big city yeah you need it due to all the stop and go ..but out on the suburbs - no point considering you'll probably drive it like you stole it more then you would in the city


im not to sure whats wrong with your cars ...my car lights the tires up all the way through 3rd if i have ESP off

honestly i'd be checking out the fuel system ...there isn't too much that can kill power in these cars honestly besides a few things but the main one would be the fuel system / injectors

low fuel rail pressure will make the car feel like it has 200hp and it won't throw a CEL either unless you really choke it out

or maybe your purge valve

when you say EC custom tune ...what did you have them modify from their off the shelf? i dont think they need to tune for cams and lifters?

one thing i've learned over the years of having a c63 is most of the problems are fuel related issues ...why? well because the engine can drink more gasoline then a entire indian tribe can drink beer during a ceremony

You must be chinese tyres. 3rd gear. 😉😉

not at all, just have full exhaust with headers and other mods so the car makes power

Do a full battery reset after the EC Tune.

N/A cars will always "feel" slower, as you don't get that crazy surge of TQ to push you into your seat like turbo cars do.

That, and the M156 isn't a TQ Monster like the N54/N55s were.

TQ makes it feel like you're going a lot faster than you really are.

Bud I don't think my throttle bodies were the problem it was all in the tune. When I sent my Ecus in to weistec when i changed over to stage 3 there were a few issues (weistec) at that stage and it seems my pump gas tune wasn't even flashed properly so that's where this issue started

The torque limitations were all over the place timing was too much and was rich as hell as soon as we flashed another tune in I gained 40wkw

I honestly think your problem is in the tune go do some data logging for me and send it over to me I will get it checked

I would start there first the throttle bodies are computer controlled therefore if they are not opening where they should be the issue stems from the ecu

Get a return done by msl or kleeman and go from there

Let me know if you need anything

Yeah, that makes sense. Thanks Phil! :y

insurance usually lets you buy the car back ..tell them you'll buy the car for $500 because thats all it's worth now (even though its worth way more) and then you get the car + the money or how ever they do it

I think you are in the wrong thread. I think you meant to respond in the thread with the totaled C63.

Post your dyno graph

:rolf::rolf::rolf:

Just speculating here, but if I was having issues I would first look at wear and tear/maintenance items like spark plugs/wires or a fuel pump, injectors etc depending on miles. Ive even read in various threads people noticed big changes when swapping out for new O2 sensors even though there was no CEL. I would also look to make sure there is no small gaps in the intake anywhere for vacuum leaks (once my airbag wasn't sealed properly and i felt low on power and i fixed it and it got better right away, didnt get a CEL or anything) or possibly a weak intake manifold (which I've read are prone to cracking). Im sure you have checked all these though. Could be a different issue for the different cars even though they have the same symptoms, i can't imagine it being just one specific cause that can eliminate the issue. In your case, i remember you had issues in the past with power being low after cams, I don't remember what happened after that if you swapped back to stocks to double check or had it retuned.

If it was o2 sensors or plugs the car would not drive good and it would be missing etc etc
his ECU has not been tuned properly for his setup or the install of the cams is not correct

Ahhhh........my apologies, I must have misunderstood what your issue was then. I was under the impression that the replacement TB from Weistec, solved the problem right away. Do I need anything? Guidance, my friend. I'm quite mystified by this whole issue and it's making me want to give up on the car and just buy something else tbh.

For what it's worth, this thread is not necessarily aimed at just my car, but any M156 motors that want to come out of the woodwork and share their experiences. The fact that I'm hearing more and more about this issue, makes me think the issue might be something that we've come up against and flagged as something to look out for, as a community.


Also - I have requested my dyno plot from eurocharged, so hopefully they'll be kind enough to share and then I can post up. I've asked that my dyno plot be overlaid vs the other Kleemann car in this country and also if they can lay my plot over a stock C63.

I was under the impression it was the throttle bodies also but my car was tuned not long ago and when the tuner was tuning the whole programming of the ECU was not correct

Basically my pump gas computer was tuned for my 60mm pulley and ms109 race fuel

So my car was running like a dog

Even when we changed the throttle bodies my car would be at 450wkw for 10-15 secs and then go down to 390wkw a run later

It was pretty FU

Dont give up man just get it retuned and go from there

While I'm waiting on the dyno graph to be emailed over to me from Eurocharged, I've managed to find out the following, after talking to the good man at Kleemann:

Max ignition should be around 24 degree's ATDC. If live data shows the car at around 15 degree's or so, it can potentially point to an inaccurate MAF.

Throttle plate opening via the Mercedes Xentry tool would show 78% to 80% as the WOT value.

Collapsed cats can go undetected for a long time and result in power losses that can't otherwise be explained. While I see the rationale in this, to me, it doesn't explain why some C63 owners with decat+tune were one time running 560hp , but now struggling to get much over 500hp.


Cams should add approx 20hp peak before tuning on a stock E63.

I recently flashes an OEtuning tune and didn't feel as though the tune helped...shortly after I began throwing crazy misfire codes and O2 sensor errors...

replaced both sensors with new sensors...car runs amazing now and I can feel the tune. I have 117k miles on my M156.

Get your car on a dyno and see what its actually doing and look at the car logs.

So I've been asking Eurocharged to kindly email me a copy of the dyno sheet over the last couple of months, but I guess they're too busy or just don't like me...who knows. Looks like I won't be able to get a copy of it from them so I'll have to go elsewhere.

In other news, last night I used my friends iCarsoft i980 hand-held scanner to do a live data run. Sadly, it doesn't freeze the peak values once reached, so I had to drive and rely on my friend to keep an eye on what the throttle opening was showing. The highest average value for the throttle opening showed as 78%. Now although this isn't a Mercedes Xentry scan-tool, it looks like it calculates the throttle opening as the absolute value, not relative. Am I right in thinking that if that's an absolute value, then the throttle bodies are opening as they should be (for an untuned E63) and I now need to look elsewhere to solve my power issues?

Also, for what it's worth...
It referred to the throttle opening as Throttle Valve Angle (which makes me assume it's an absolute figure)

The below figures were a snapshot taken by cellphone camera at high rpm (I told my friend to take pics above 6000rpm) so they mightttt not make total sense or be conclusive for the moment:
Intake manifold pressure was 1bar (well...it's not going to be any more than that, lol)
Right o2 sensor (downstream) shows 875mv
Right o2 sensor (upstream) shows 1.04 (didn't have any unit conformity like mv etc)
Left o2 sensor (downstream) shows 865mv
Left o2 sensor (upstream) shows 1.16 (didn't have any unit conformity like mv etc)

Bud I still think it's the tune

Throttle bodies are computer controlled I recon your tune is not good

Apparently I'm on the stock tune now y'know...I asked MB to do a software update and erase the tune about 6 or 7 months ago tbh.

Baffling, eh?

If the tune is off (and please excuse my ignorance here), but the throttle bodies are opening to maximum....I'm struggling to understand where the ~70hp has gone. Even if the ignition timing was down by 10 degree's, it wouldn't account for such a deficit. The part where I hear you mention 'torque limiters' is where I get confused...I lack the knowledge in that area.

It's a pity that there aren't any tuners close-by that I can work with other than Eurocharged, hence why it's a slow, dull path to try and solve this mystery. Yet I saw my friend with his Kleemann C63 take down an E60 M5 the other week, while my car struggled to fend off a stage 2 Golf R a couple nights ago...ahem