Identifying w213 E63s flat spot issue

[irfan1712]

Hi all

im after some thoughts. Ive had my w213 E63s for over two years. I had it mapped last summer by MSL and it’s been even more fantastic since.
Recently however, the car doesn’t feel the same. Few weeks ago I remember it flagged up a load of issues - brake assist not operable, electronic diff not operable, amongst a few errors. Turn the car on and off and they disappear and won’t appear again until it fancies it. This also happened when I had the car back in 2018 and a control unit was changed under warranty.
Anyway. Since the errors showing up again a few weeks ago , I’ve noticed when I plant the accelerator it feels flat in the high rev range. Low down in any gear and it pulls like a savage as usual, but the power delivery goes almost flat from mid to high revs. It’s never felt like this, and certainly since the map it’s pulled relentlessly from 0 to pretty much the Rev limiter in any gear.

No errors on the dash now, no CEL or obvious sign something is wrong. It just Defo isn’t right. The error level above might just be coincidence timing wise. Could it be turbos or something else induction related? It’s due a service and is booked in March for it. Other than that I’m not sure where to start looking at it really as there’s no noises or errors to follow.

It’s a 2017 car with 45k miles on it.

Appriciate any input you may have!

 

[Steve84N]

Call MSL as they may have experience of the issue.

 

[BigFishJohn]

Get a code scan, see if your exhaust flaps are sticking. This can drop the car to reduced power mode.

Obviously pop into see MSL and they will do a full inspection for you on it.

 

[irfan1712]

Thanks for the info. I spoke to acid at MSL yesterday and before anything he suggested the car getting serviced first. It’s actually due a service and is booked in two weeks time anyway. Possibly a change of plugs might solve it.
If no success he said to speak to him again and then we start finding the problem.

once the car was warmed up a give it a bit of a poke on the way home lastnigjt from work and it felt fine although they were short bursts. Bizarre!

 

[irfan1712]

Get a code scan, see if your exhaust flaps are sticking. This can drop the car to reduced power mode.

Obviously pop into see MSL and they will do a full inspection for you on it.

hi all, just thought i'd report back.

the issue has been on and off for the last 5 weeks or so. it was serviced with Mercedes last week (fluid changes, plugs were not changed).

the issue is still there. In any gear (seems to be mostly higher gears and mid to high revs ) where there is a bit of load on the engine, if i flatten my food on the pedal, the engine screams, it drops to the right gear, but there is just little to no thrust. I looked at the Boost indicator next to the speedo and it basically stuck about a third of the way - regardless of speed or gear no matter how much i tried wellying the pedal it was as if something was holding the boost back.

i read a lot about sticking exhaust flaps as per BigFishJohn's quote above. i've confirmed tonight sticking a torch down the tailpipes and watching the valves move after i got someone to press the button inside, they move a few millimetres, say 20 degrees if that. If i change it to race or sports+ it still does this, although it does the cracks and bangs so it still sounds louder.

Can a sticking exhaust valve cause such a dramatic change in boost pressure, and in turn restrict general power of the car? Low down gears, and low down grunt is fine - it seems to be higher gears and higher revs.

Is it worth going back to the dealer or should MSL or somewhere else permanently open the valves, or remove them all together? is it coded or a physical remove job? sorry for the long post! appreciate the input.

cheers

 

[st13phil]

Is it worth going back to the dealer or should MSL or somewhere else permanently open the valves, or remove them all together?

My first suggestion would be to put it on a set of rollers (probably at MSL) and see what's going on under load. You could fish around for a long time and get nowhere without an effective under load diagnosis.

 

[Cyclone1]

Sounds like there is an underlying issue based on you experiencing multiple system type errors a couple of years ago. This may or may not be related to the current flat spot issue.

As said above get the car scanned for errors and see if any old errors are stored. Sort this first, then possibly go down the route of putting on a dyno or road test with the diagnostics connected, this may flag what the issue is. For example it could be as simple as changing the plugs, so as a method of elimination I would have insisted they were done at service time. There are many other probable causes, but follow a logical process and fingers crossed it will be something simple and found quickly.

 

[irfan1712]

thanks mate.

Spoke to acid yesterday. im almost certain the butterfly valves not working are my issue - the symptoms are certainly there and hopefully its a straightforward fix of removing them and coding them out.

as im now making the day out trip to MSL next week, im now considering downpipes lol. When in rome and all that. He only has catless there - which i would really like, but my car is a proper daily driver. Would catless downpipes be over poweringly loud? Does going catless cause any drone in the cabin? Long journeys bearable? im retaining the standard mid and rear sections. Just my rear valves will always be open so i guess thats a bit more noise from lower revs anyway, will it all be too much.

of course priority is to sort this issue out first, and if successful i'll get the downpipes done on the same day.

Currently running 707bhp and 850lb ft off MSL's stage 1 map - quite curious to see how much more power a downpipe would give, granted i dont think that torque figure would increase much as its a huge leap as it is.

 

[MrE63Smike]

thanks mate.

Spoke to acid yesterday. im almost certain the butterfly valves not working are my issue - the symptoms are certainly there and hopefully its a straightforward fix of removing them and coding them out.

as im now making the day out trip to MSL next week, im now considering downpipes lol. When in rome and all that. He only has catless there - which i would really like, but my car is a proper daily driver. Would catless downpipes be over poweringly loud? Does going catless cause any drone in the cabin? Long journeys bearable? im retaining the standard mid and rear sections. Just my rear valves will always be open so i guess thats a bit more noise from lower revs anyway, will it all be too much.

of course priority is to sort this issue out first, and if successful i'll get the downpipes done on the same day.

Currently running 707bhp and 850lb ft off MSL's stage 1 map - quite curious to see how much more power a downpipe would give, granted i dont think that torque figure would increase much as its a huge leap as it is.

so how did you get on at MSL did they find the problem was the flaps or was it something else and did you get it down piped what power did it make after map and OPF and CAT removel??