cij911

Curious did you test each coil? What was the resistance in the primary and secondary (do you have factory specs)? I did a quick search and did not find anything. I am guessing it is on MB WIS.

karpetcm

I changed plugs to factory plugs gapped them to.022 drove it for 5 min and it was missing those were now my 3rd set of plugs. My mechanic had the coils ready to go, I drove back put in the new coils and the car drove just fine. Different car but my wife's car when I tuned her car all her coils went bad within the first 5min of the tune. I was told it was going to happen by a few and swapped them and no problems since. The plugs on hers were changed as well before the tune.

tonyhype77

Not in this case. I have an AMS tune on my E63 and burnt the spark plugs and coil pack 5k miles later. When they replaced them I kept them stock, but when they go again I will forsure get NGK plugs.

mrweelr

Great thread guys and I’m very glad I found it. I just had AMS tune my 16 CLS63S and today doing a high speed pull up to 140mph, the car shook, had no power and threw a CEL. I pulled off and stopped and restarted the car but the issue persisted. I told my GF I think I just blew the motor with 34K miles on it :-( So I drove the car gently to where we were going and parked it for a while. Came back an hour later and to my surprise it ran normally again with the tuned power, but CEL was still on. I did a few hard pulls and it ran normally again, whew!

When I got home, I scanned the ECU and it had the P0300 Random Cylinder Misfire as well as cylinder 5, 7 and 8 misfires. I cleared the codes with my scanner, but the P0300 and P0305 won’t clear and the scanner indicates the codes are PERMANENT. I tried disconnecting the main battery under the hood for a bit and then rescanned, but the codes are still there. I’m thinking I just need to drive the car around a bit and they’ll clear themselves?

Anyway, the car has 34K miles and I’m sure the plugs are original, so I’m hoping this is just a case of old plugs with wide gaps. Will order some OEM Mercedes plugs and gap them at .022 and see if that helps. If I still have issues with misfires after that, I’ll start moving coil packs around to narrow it down.

Anyone have the correct Mercedes part number for the newer colder OEM plugs for the M157?

Tonypw

iTrader: (1)

I had the same problem. Make sure you have the correct spark plug (heat range) for your application and indexing the plugs is mandatory for the M157 engine.

alexdou111

hello everyone, I a building a stage 3 M157 (in a w222) at the moment and was wondering, what was the latest news regarding which spark plugs to use for such application?

I have stage 3 modified turbos to be installed and am targeting to reach 800hp with this, thanks for pointing me into the right direction on spark plug choice!

S63C4

I know this is old, but this post made me ROFLOL. "If the gap is too small, the flame kernel will not grow" HAHAHA... "Small gap = short spark duration." HAHAHA... "Large gap = ignition system won't cope..." HAHAHAHA!!!

And then the topper of them all... "rule of thumb is reduce the gap about .004" for every 50 hp you add over stock"

SO... In my Weistec W.4 equipped, 1010 HP M157, let's do the math, shall we? 1010 - 577 = 433 / 50 = 8.66 x -.004 = -.03344

...According the brilliance of gaspam's logic, my plug gaps should be non-existent, MINUS .01144 that the negative electrode gets SH-MUSHED into the positive! ROFLMAO!!

Thanks for terrific advice, gaspam, and even more for the laughter!

Rule of thumb: Never change or re-gap brand new spark plugs. (Just check 'em, maybe.)

w222Dan

Hi this my first day on the forums I have a 2015 s550 wit the m278. I want to change spark plugs for maintenance, are the ngk laser iridium’s on weistec good for my car even though I’m completely stock? They say u can use for stock or highly tuned cars but I jus want to make sure it’s ok before spending 200 on spark plugs. I’m also gonna add high flow intake panel filters

PeterUbers

here's what you need; high flow filters sadly will not categorize your new ride as "highly tuned" don't care what the naysayers say.. 😉

https://www.fcpeuro.com/products/mer...vD_BwE#fitment

Baltistyle

Listen to Peter, he knows what he’s saying. Make sure you also read about spark plug install on these engines and whether or not indexing is used and whether or not you can accomplish that. The labor is simple but only if you do it right, and with stock Mercedes plugs. Using the wrong plug in the wrong indexed position could/will literally destroy your engine. There is no “just screw it in till it’s tight” with these cars.

This is not to discourage you, but so you learn exactly what is needed before making a mistake. I diy almost everything, but only after exhaustive research.

have fun

PeterUbers

^1000

S63C4

You could certainly go with what Peter recommended, or use the ones I put in my Weistec W.4 equipped M157, -> NGK (91784) LKAR8BHX Ruthenium HX. They have crush washers which make 'em much easier to index. They perform beautifully and will outlast any other plugs. Whatever you do, don't pay Weistec's RIP-OFF price!

berti_00

Oem. Set them to .022. New coils and all.
I had no issues
this is just a maintenance thing to get of my head

SilverE5588

Did you go about indexing , or just torqued to specs. I overthink it , surely an mb tech is torque and send it in reality ha..

BCP

OEM plugs are supposed to index properly when torqued to spec due to the precise thread start location.

berti_00

Yah indexed to factory spec. They almost came properly indexed from factory but I went through all of them to make sure they are .022

PhuongNguyen

So the plugs from the dealership and the Bosch ZR6SII3320 is the EXAXT same plug right? No need to pay dealership prices?

PhuongNguyen

what were they set at fresh out the box? .0275 right ?

BCP

That is gapping them - indexing refers to the electrode gap alignment when installed. It is wise to check the gap before installing them - you never know how many times any given plug was dropped or bounced around in its life before arriving at your door.

It is my understanding the MB branded plugs, while manufactured by Bosch, are made to MB specs for proper indexing; each plug is supposed to have the thread starting point in the same precise location. The Bosch branded plug, while it is compatible, will have the threads starting in different locations. You can by the MB branded plugs from FCP Euro and utilize their free lifetime warranty when it comes time to change them again.

NoVAe63s

Just ordered the FCP kit, Bosch branded plugs have .028 on the box.

bentz69

Spark plug bump...

Ive read everywhere the bosch 7430 is the exact oem equivalent to the MB branded plug. I had a failed #6 plug and went to the dealer to buy 1 oem plug to keep me driving while 8 bosch 7430's arrived in the mail. These threads look identical to me and specify 23nm for both MB oem plugs and bosch equivalent. If the bosch plug specifically states 23nm just like oem, thats solely for proper indexing.

The only visual difference I see is
OEM plug has Z6S113320R stamped on the plug
Bosch plug has ZR6S113320 stamped on the plug

The electrode is different as well