Hey all,

I picked up a certified '19 E63s wagon a few months ago. I noticed the car does not get to full boost on the gauge in the instrument cluster and it gets stuck at about 300-350hp. From my research this seems like a classic case of the exhaust flaps and/or actuators getting stuck or failing.

Since this is a CPO car, I took it to the dealer to diagnose. I provided them with two videos (links below) showing runs to redline where the car does not make the boost/power/tq it should. The car isn't throwing a CEL and I didn't see any active or stored codes when I scanned it. The dealer is claiming the car is fine and the car is making full boost despite what the gauge shows.

I specifically followed-up to ask whether they (i) confirmed through Xentry that the exhaust flaps and actuator motors are working correctly and (ii) have ruled out broken/melted catalytic converter. I am waiting to hear back but i am not optimistic.

I have a favor - can someone with a W213 e63s, preferably stock, post a photo and/or video showing normal behavior of the power/boost gauge?

Here are link to my own videos:

- Video 1 of 2
- Video 2 of 2

Thanks in advance!

 

go to a different dealer if you can. should be super easy to diagnose.

 

I will probably end up doing that, but they might try to charge me a $300 diagnostic fee despite not finding the problem.

What peak hp/tq numbers do you see on your gauge?

 

eyes on the road when it peaks, but I see 603hp 627lbft

fwiw I had my exhaust flapper fixed last week for this issue, but I had codes for no voltage to the flapper. I would get full torque up until 2500 rpm, then it would pull boost and hold power at ~350hp.

good luck!

 

thanks - any chance you can send me a pic of the gauge? stay safe...

 

So here's the update from the dealer. This is puzzling because they are saying the flap is stuck open? I obviously don't agree that the boost/hp figures are correct, but let's see what happens after they replace the part:

Road tested with xentry computer hooked up monitoring values. No signs of obstruction in cat pipes from values. Values on that topic would trip codes and check engine light when out of spec due to emission standards being monitored. Boost and horsepower values are normal for customer display screens. The topic of exhaust flaps is correct and don't always put a check engine light on. Function tested both flaps. Actuation of Left flap is ok. The Right Flap is stuck in open position on actuator. This part is covered on CPO. We will replace that part. This will bring back control on making right side exhaust quieter if customer wants it to be. In current state of Right side flap stuck open which is not affecting horsepower.

 

I’m now having this exact same issue so with a recently acquired CPO wagon. Did the actuator fix restore you to full power?

I’ll be scheduling an appointment with the dealer as soon as possible. This might speed up my purchase of the Renntech valve module.

 

Yes, the new actuator restored me to full power. I have the wagon at a nearby Renntech dealer getting the exhaust valve module installed. I'll let you know what I think after it's installed.

 

Either of you guys gets your wagon from MB Asheville?

 

I got from a dealer in Ohio and apparently the car was owned by a local businessman who used to be a drag racer!

https://www.nhra.com/news/2016/fast-eddie-schartman

 

Nope mine was from MB of Scarborough, Maine

 

I’ve been intermittently getting full power back and losing it again. It’s driving me nuts!! Any tips for getting the dealer to replace these under warranty? I’ve heard conflicting accounts of whether or not CPO holds for getting this addressed.

I’ve also heard that the Renntech module could cause issues since the valves apparently self test every now and then? Either way I need all my juice back, can’t wait to get this thing to the dealer next week.

 

Update:

Dropped the car off at the shop last week. It’s been there for a whole week waiting for a master technician to take a look and diagnose. They confirmed they were able to duplicate the power cut after 4K. I asked them if there were any Xentry codes for flap / actuator issues and they insist there were none.

Gonna call and check in tomorrow because this feels like a long time to diagnose what seems to be a fairly common issue with these cars.

 

Any updates?

 

I've been bitten by this bug.

The Interesting thing is I have a flap control module and have been running the flaps wide open for years so didn't think this was it. The only thing "changed" was getting big tires. After the tires I've been noticing about 50% of the time I don't have all the power! Mostly between 60-120kph. Then I remembered this thread.

Today I flipped screens so my dash has the BOOST and HP gauge and when the car is slow and ******* it never gets above 330ish HP. UNLESS I stay in it to over 120kph then around 130 even if stuck at no/quarter boost and 333HP it will seem to figure out things at higher speed and it opens up to 603HP. Of course this is way to late in the game, I need HP from 50-120 not above 120.

Like I mentioned at first I thought the big tires were weirding out the car but now I'm not sure. So on my last drive I put the flap control on "bypass" mode instead of keeping the flaps open and so far the last 10ish pulls have been all the boost and 603HP. I will leave it like this for a while and if the problem is gone, will flip back to always open and see if the computer starts pulling boost again.

It is quite embarrassing flooring it, making so much noise with the flaps open, and barely pulling away in traffic. A pickup truck could probably out accelerate me. Oof. I really hope this fixes it and it's not the 28" tires causing grief.

 

Interesting, I never thought to push to higher speeds and see if the power came back, I mean I got up to 80 mph and still had the lack of power. In my experience, it got worse over time until I got my valve situation addressed. I really don't think it's your tires, especially if you're on stock wheels. I have a CPO warranty on my car, so they replaced the valve on the right side, I believe they also had to replace some solenoid and then they lubed everything up. Since then everything has been perfect, no power cuts.

From what I understand, the flap control module is a temporary fix if you start having this issue without one installed, but once you start having it with the module, then you have to get the valves replaced, or manually lock them in place (someone on this thread did that). Since your car is a '23 it should honestly be under warranty, hopefully it's just a valve replacement and not the full exhaust like some people have been quoted.

 

Very delayed! But the dealer swapped the valve with a new one, replaced some solenoid and lubed things up. It's been perfect since

 

That is the weird part - flaps are fully open and it's doing the low HP shenanigans.
And
Because I'm a paranoid guy every month or so I have been letting the car open/close the flaps so they don't seize in the open position. Maybe that was actually my downfall.

Did anyone defeat this with CPC always open programming? Or does the system still pull HP if it thinks something is wrong with the flaps?

 

It's like first bit in the smoking tire podcast today. They were talking about an 8-cylinder replacing a 4-cylinder but it didn't have that much HP so it sounded like it was going fast butit was like walking speed.

 

Update

The problem has gone away and hasn't happened for a few weeks.

Car is going in for Service B tomrrow I will mention it and see what they say.

 

Well today on the freeway there was a left lane sticker
I mashed the gas to get around after giving 2-3 chances for them to move over. Car took off then HIT A WALL at (ahem) kph and all power went away.
and from then on zero boost on the gauge, and only 400HP.
For the rest of the 45 min drive I kept testing - swapped modes, sport, sport+, C, etc. and could never get any boost at all. Tried different gauges and cluster designs, all show zero boost. Not even 1/4 boost like before when it got stuck at 333HP at least then it had some boost about quarter gauge. Also weird it got stuck at 400HP this time and not mid 300's.
Played with the aftermarket exhaust flap control too. Closed, open, bypassed, only 400HP and zero boost in all tests.
Exited the freeway and stopped at the end of the offramp, quickly turned the car off open and closed the driver door turned the car on and VOILA instantly took off at full boost again.

No CEL or any other indications anything went wrong.

 

Yeah this sounds exactly like how mine progressed. Cutting off the car would temporarily bring power back sometimes but it would fail me the most when I needed it. Seems the car is still under warranty, I would go to the dealer and tell them to take a look at the exhaust valves / solenoids. It frustrated me to no end, but once I got mine replaced under CPO warranty, it didn't come back (it's been two years). I never got a CEL the whole time either

 

Today it happened right when I needed it most.

This time when the boost cut to zero the windshield completely fogged up and I thought I could smell coolant.

Key off door open key on - fine again but only for 5 minutes then again zero boot, 333 or so HP. This time no fog, Power cycle and full boost again.

Scanned with HP Tuners no CEL or codes.

These cars are SLOW with zero turbo!