How to Increase Throttle Response on Mercedes S550

The 2013 Mercedes S550 W221 series car has a powerful engine known as the M278. After a while the gas pedal will not feel as responsive as it once did when the car was new. I'll tell you a few minor repairs you can do yourself that will help your Mercedes get excellent throttle response back. In other words, if you barely press the gas pedal and you don't get pushed back in the seat, its a combination of a few different things that are getting a little worn out and once you replace these things your M278 is going to become very happy again and you'll experience the true torque of this car as if it were new.
Use LOCTITE SF 7200 for removing old gasket material from the face of where your cam timing chain covers bolt to the engine and then clean metal surface with LOCTITE SF 7063 before putting new gasket material on. Don't use sand paper or a scraper, I'd recommend using a cotton towel and saturate it with the LOCTITE SF 7200 then keep working it on the metal until all the old gasket has vanished.
Get Bosch Oxygen Sensors from Napa Auto Parts, they are the same exact ones Mercedes sells at their parts counter as Bosch makes them for Mercedes. The Cam Magnets and Cam Sensors, I'd get them from a Mercedes dealership parts counter with your VIN #.
Remember, this is a high performance engine which performs at its best with high octane gas, so I also highly recommend you use Chevron Premium gas only. It'll keep your engine clean and running its best. I know, premium at Chevron is kind of pricy right now, but if you use cheaper gas from anywhere else, the money you save over a year or more will end up being spent anyway on repairs to your fuel system. Great engines don't run well on cheap gas.

[@ka0tyk]

o2 sensors replaced every 30k miles? you're crazy. dont just throw parts at your car. get a good bidirectional scan tool with live logging so you can properly log these sensors and such to see if they're responding properly. replacing timing cover gaskets isnt "to keep pressure in the engine"... that pressure is relieved via the PCV system and lots of crankcase pressure is NOT a good thing... replacing the timing cover gaskets on m278 engines is because they're prone to leaking. the cam sensors are prone to cracking and allowing oil to seep up into the wiring harness and causes damage. if you want throttle response clean your throttle body blades and surfaces from PCV systems recirculating it back into the intake for emissions. if you want to stop this from happening, put a oil catch can on those hoses to separate the oily residue from the air so that it doesnt coat your throttle body, intake manifold and most importantly the backsides of the intake valves on these direct injected motors. they are prone to the intake valves getting caked on oil residue and disrupting flow or worse, creating hot spots on valves which can cause them to fail and lose compression in cylinders. keep up with oil changes even before the recommended oil change intervals. these engines are prone to cylinder wall scoring... a $100 oil change every 5k is better than a $10k reman engine and almost just as much in labor because the engine transmission and cradle has to be dropped from the car... a LOT of labor at $100-200 shop time per hour.

[@V12Buickguy]

This guy is an idiot and just making a video to hear himself talk.

[@ilhommuminov708]

Dude I see either you are a mechanic or have the same car and had this type of issues? Some people says even no matter what if you change your oil every 5k it will happens is it true? Also there are a lot of people saying it’s a reliable engine can run more then 200.000k and some says at 90.000k you junk it it’s hard to believe people now days but yeh or people scared or making money by making a such a videos on KZbin as I said hard to believe Be safe God bless

[@kauaigold]

Vacuum pump check valve, will fix a lot of turbo issues such as "low boost pressure" message and sluggish feel when trying to pass. Costs $10 if you get the valve for a 2012 ford fiesta (same pump at M278 mercedes, jobber was used to supply pump)

[@toddfilo]

The pump is not the same, but the check valve will fit. You have to be wary because the valve on the Benz is not the same internally as the ones for $10 on ebay. It may work well enough that most people won't notice, or maybe they're happy since it works so much better than the broken valve. I can tell you I tried one and it was a fail. I knew it as soon as I saw it, but tried it anyway just to see. The cheap valve cannot respond as fast or seal as well as the oem valve and you lose vacuum strength, which is desperately needed for turbo control. Check for yourself by taking the valve apart, it's quite obvious the $10 valve is crap. How much vacuum an engine/turbo needs for wastegate control will vary, a lot, but the M278 needs a lot of vacuum. In fact, it cannot fully close the wastegates at peak power with the oem valve, so even the slightest loss in vacuum from there means the wategates are open even more. That check valve is key in netting max vacuum available, as is the turbo solenoid and battery voltage at peak power. The solenoid may seem fine but it can cause power loss too. Voltage can drop when floored and that means less vacuum, thanks to the solenoid not getting the voltage it needs. All the more reason for the vacuum from that check valve to be at it's absolute highest to hold the wastegates as closed as possible. Fyi the low boost pressure warning will only trigger when the boost is painfully low, and I believe for 5 seconds straight. So you could have half boost and it'll never trigger.

[@gusf8451]

I have removed those turbo pipes before and used the same clamps and they work just fine.

[@MercedesMechanic]

You got lucky, the more times those clamps are removed and put back on they eventually stop working. Reason I recommend you get more is because they're only $6 and if you are putting them back on and they don't tighten you'll in some cases have to order them and wait which in my opinion is a burden because there are other things you can't put back on until the pipes are back on. Its a preference I suppose but the dealership doesn't always have extra in stock for their retail customers.

[@toddfilo]

@@MercedesMechanic I too have reused them many times. Maybe people are over torquing them? I haven't have an issue, yet, but I suppose I should buy some in case they break on me one day and I end up in the situation you described :o

[@MercedesMechanic]

Precisely, the more parts I buy from dealer I've learned they don't have the simplest part in stock at the parts counter and usually have to order them and when I'm doing a repair my time is money so I don't like to stop because a $3 clamp won't tighten. I would also agree that some dealer techs are over tightening things which cause problems as well, it seems I'm always having to fix their mistakes. Few months ago I replaced an oil pan because the dealer tech over tightened the oil plug and cracked the pan which is impossible to do with a torque wrench which tells me he/she didn't use one. I see a lot of coolant caps overtightened as well which ultimately damages the tank neck and the cap. @@toddfilo

[@MercedesMechanic]

Also when buying a used S Class its impossible to know what work has been done on it in the past so for all anyone knows the clamps could have been removed and put back on 12 times before you buy the car. I never penny pinch on repair because it'll cost me more in time not to mention hassle.@@toddfilo

[@toddfilo]

@@MercedesMechanic I'm more of an under torque kinda guy, and always my calibrated elbow ;) Rod, Main and Head bolts I'll break out the wrench, but that's it. I've seen that oil plug thing too. I always wonder how the F they manage to do that. I had assumed a defect in the cast alum because nobody would tighten it that much, right? Well, a lotta people don't think like we do. In fact, yesterday I was making repairs to a test engine where the tech was using an impact on it to tighten bolts. Not sure how many times this was done, but a lot! Now the threads on 34 bolts are gone or barely there. It'll be a pita to fix each one. It's first on my list of things to fix next week, and will take days at best. So I feel your pain!

[@tonycol7074]

With all the usable knowledge, sure say some bizarre things. Like "when you take it to the dealer." 😮

[@tariktokalija452]

What milage is on that engine, and how much oil does it consume between service intervals?

[@MercedesMechanic]

If you drive a lot of highway miles in a Mercedes, the cars manual tells you it will consume a quart of oil about every 1000 miles. The low oil message will appear on dash, when it does, it should be a quart low.

[@tariktokalija452]

So that means if you change oil regularly every 8k miles, it burns 8 quarts of oil between oil change intervals... that's a lot. Perhaps cylinder bore scoring might be a cause for such oil consumption?@@MercedesMechanic

[@MercedesMechanic]

Not sure how they determined it but I’d change the oil at no more than 5000 miles and either use Mercedes oil or liqui Moly oil. The tradition oil change rule for synthetic oil was 10,000 but that puts unnecessary wear on internal parts of the engine. Just remember an oil change is $100-$130 but an engine is thousands, so if you like your car to last change the oil at 5000 miles or less.

[@andrehafrian408]

Correct if I’m wrong but i think it burns oil because the turbo burns it since it’s oil & water cooled turbocharger i think

[@MercedesMechanic]

A turbo water cooler was placed on top of the engine on some models of the w221 and some did not have it, it has its own separate coolant system. Not sure about the oil but in the last 20,000 miles I've put on my 2013 S550, the low oil message only came on once and it took a quart like the manual said it would. I have not experience it using a quart of oil every 1000 miles like the manual says so they must have said it in the manual just to cover their ass incase the engines were using it. I change the oil using Liqui Moly at 4000-5000 miles and I get the filter from either the dealer or Napa Auto Parts has one thats made by the same company who makes it for Mercedes. I also use a new plug with new copper crush washer. I will not use a cheap filter or cheap oil. If I idle the car a lot in the summer, I'll change oil even sooner as idling wears the oil just as driving does. @@andrehafrian408

[@CL500MBZ]

Why didn't you show the entire process on the video?

[@MercedesMechanic]

I already did the work, don’t worry it’s easy if you are mechanically inclined. If not, take it to your local dealer and tell them you want these things done.

[@jrm163]

This is the first time I see a merchnics suggests keeping replacing parts before parts actually break! Why not replace all head bulbs and so on? They all have a lifespan. Non sense!

[@jrm163]

As to the clamps, definitely it’s due to the merchnics’ fault by over-tightening them. Sigh, you are advertising more work for yourself!

[@user-mu1rw1qr2u]

Do you have any idea of the cost of all them magnets & sensors are 😂😂🤷‍♂️

[@MercedesMechanic]

call dealer parts dept

[@toddfilo]

There should be no crankcase pressure. If there is, you have a new problem. Replacing the gasket on the timing covers is to prevent oil from leaking down on the alternator, which can be spendy to fix. Or to simply prevent a messy oil leak period. If it leaks, air or oil, it does not affect throttle response. Try removing your oil cap and see for yourself. Of course you can reuse the turbo clamps. I've used them over and over many times. Everyone does. If you netted better throttle response then you fixed something somewhere, or maybe reset the ECU by unplugging the battery? I have a hard time believing it was anything in the video.

[@MercedesMechanic]

When the car is going down the road at 70 MPH and the rpms are way up, if you could remove the oil cap the oil will come flying out due to the pressure that's built up in the crank case. It does not matter however when the car is at idle, you're correct theres no pressure sitting idle.

[@toddfilo]

@@MercedesMechanic The oil will come out because the chain is flinging it it. If you have pressure blowing it out then you have a problem. Mine has 70k on it and there is zero pressure, even under boost. I actually measured mine, have you?

[@V12Buickguy]

You invalidated every bit of poor advice in this video when you said "cadillac" converter...

[@garysaunders310]

Man my engine will explode if i try do any of tht

[@MercedesMechanic]

It may also give you whiplash when you touch the gas pedal, be careful

[@JD-ym7nv]

I have had a significant repair caused by failing cam sensors. The cam sensors fail and then ruin the wiring harness. It is a $10,000 engine out repair as oil escapes and wicks up the harness. Recalled up to 2011. Auto Auction Rebuilds KZbin had same problem in 2014. He did pigtail repair himself. Mine is a 2013. Mercedes makes a pig tail which connect the harness to the sensor which is supposed to stop the oil should they fail again. My Mercedes has only been serviced by Mercedes and has 62,000 miles on it. I had the pigtails installed from watching the KZbin. Total repair costs $10,600!!!! Crazy!!! The Mercedes mechanic was not aware of these but I gave them the model number and they put them in. This is an inexpensive insurance plan. Apparently Mercedes uses same cam sensors on other engines but has not put a recall out after 2011. Mercedes has not stood by their product and I will never purchase another Mercedes. I currently own 2 Mercedes. :-(

[@MercedesMechanic]

It happened to my 2013 s550 at around 68,000 miles. The pigtails do not stop the oil, they intercept it and they need to be checked every oil change. When oil gets in the pigtails, you then have the opportunity to replace pigtails opposed to the entire wiring harness, that’s the concept. The repair on mine was $16,000 as it ruined the computer and other sensors including the harness. Dealer service director and shop foreman told me it’ll happen again and advised me to periodically check the pigtails for oil and keep extra ones on hand.

[@JD-ym7nv]

@@MercedesMechanic Thanks for the additional information. I suspected the sensors might fail again. I also assume the pigtails were a buffer not a fix. Thanks for the advice as I will have MB check at each service. I still think it’s crazy that MB has not issued a service bulletin.

[@MercedesMechanic]

@@JD-ym7nv there was a bulletin but these issues went far beyond what they were expecting. It’s happening all the way up to 2020 models from what I’ve learned. It was such a massive issue that the dealer in west palm beach were giving the pigtails away like Halloween Candy. I spoke to the C suite at merc Benz USA and they said they’ve washed their hands of the issue and will not be doing anymore for the M278. It’s a storm that’s passed already but still leaving victims here and there. Dealers are happy making a mint on this repair for those who can afford it without question. Just unplug them periodically and stick a Qtip in the plugs, if it’s clean plug it back until later and check again. ZZ Performance on eBay made pigtails for the cam sensors as Mercedes only made them for the cam magnets.

[@JD-ym7nv]

@@MercedesMechanic Thanks for the additional info. My check engine light came on . Said it was a failed coil but they found the oil leak at the cam sensor and it went into the harness. No computer damage but still $10k. Crazy :-(

[@MercedesMechanic]

@@JD-ym7nv FYI, Apparently a dealership told me last year they can flush out the wiring harness without taking it out, much cheaper but they didn’t say how much it cost.