2010 E550 (RWD)

For some reason, under hard acceleration, I will randomly get the “ESC Inoperative” light along with a near 3 second delayed throttle response. This doesn’t happen every time, but it probably happens about 20% of the time that I accelerate hard. It is very frustrating. Anybody have any guesses?

 

1-- FUEL :
i think this is when you check your fuel pressure under load... your starved trims will be positive.


2 - - WAIT.... NETWORK:

My mistake! This is not mechanical problem but ECU delayed networking with ESP wheel brain.

You'll need to scan your car to see what both passed/current faults say about potential highspeed CAN chaos.

What I think is going on is the CAN-C between ESC to ECU is impacted by retransmits and crashed module traffic...

Essentiely the brakes are vetoing acceleration
I don't think the usual wheel sensor can do that.


3 - - - DONUTS:
me stupid again, yes

You're trying to burn the wheels on MB V8 to get street attention:
Nothing wrong with car yet - - Simply RTFM to find the menu option that deals with that automatic protection.
✌️

 

I've starved my car of fuel a few times and it simply lost power, like the key was turned off/on. Just a split sec off, then back on for ~a sec, repeat until I let off the gas. No CEL, codes etc.
My thought was your traction control, or something related, is bad so when it engages and nothing happens it'll pull harder on the throttle, plus alerts you it isn't working right. Just a guess because if my brakes during traction control aren't cutting it, it'll pull the throttle so hard it's basically down to an idle. It also seems to me the worse the incident the longer it takes to restore power. So the wheels are clearly not spinning anymore as a result, but I sit there with waiting for power to return, which seems like a long time but probably 2 sec. So I picture if the brakes were not activating, that's what it would do any time the tires broke free.

Also, something that has happened to me that is very much like what you described, minus the warning, is hitting the rev limiter. My car has two rev limiters, a soft limiter at 6k that supposedly kills fuel to some cyls, but not all, to slow you down, and a hard limiter at 6370 that kills all fuel. It won't recover from this until it slows down to 5600, which takes a while. It can do this for several reasons but the gist of it is the tranny isn't smart enough or fast enough to shift correctly, so it over revs.
Not sure what your rev limiters are set at, but if you think that may be your problem I think I have your limits on my computer.

Tire wear is, for me, a big factor in traction. The more they're worn the easier it is to both spin and trigger traction control, and over rev because of it. For me, new tires it's not much of an issue, then at some point with ~ a third of the rubber gone, it would happen quite a bit, and so on until when at the wear bars on the tires I could spin the tires with ease, even when not intentional.

When wheel spin was NOT the cause, I could still hit the rev limiter in both 1st and 2nd gear. One of two scenarios is I floor it from a higher gear and the trans downshifts to 2nd when it should've been 3rd. Basically I'm doing ~55, at low rpm, and floor it. It downshifts to 2nd, revs shoot up, but when it hits it's already past 6 and a split sec later hits 6370. From my perspective, I floor it, it pushes me back in the seat for a spit second and Poof, shutdown. Then ~2-3 seconds later it finally slows to 5600rpm (~55mph) and 100% functional like nothing happened. The way the trans is programmed it apparently doesn't think to upshift while shutdown, so I'm still in 2nd when it recovers, and it's too stupid to shift into 3rd in the first place to avoid all this.
The other reason, in 1st or 2nd, is simply because it doesn't shift in time and over revs. The rpms are rising too slow in 3rd for the 3-4 shift so the trans has no trouble shifting before the hard limiter. In 1st or 2nd things simply happen too fast. After logging tons of data I see normal shifts are anywhere from ~5600 to 6000, depending on how it feels. It can, however, go well beyond that may shift as low as 5000 on up to just shy of 6500, which is quite the range and I don't know why.
Fyi I raised the rev limiters which is why it can go higher. So now the soft is 6300, hard 6500, recovery 6250 and this solves my problem. Since it sometimes shifts at >6370 on it own under normal conditions, it proves it's too stupid, or I should say the people who programmed it are too stupid, and it's an oem problem. Your car is a little different but probably the same knuckleheads programming it.
Fyi the tach is slow to keep up so the faster things happen the less likely it'll show it, at least on my car it is. I could hit the 6370 limit but the tach never hits 6k. This may also be why I could break past the 6k soft limit almost all the time, because I can only assume it didn't even know it hit 6k yet.

I suppose as a test I'd spin the tires at lower rpm to see if it still does it. I guess I'd just power brake it, or however, but keep the rpms below 4-5k to be sure the limiter is not involved. And of course do it with and without traction control to see if that changes anything. If this doesn't cause it then I'd lean toward the rev limiter thing, but that dash warning leans hard towards traction control, imo.