S-Prihadi

I have the autotool spark plug tester the twin hole one, they are NOT for MB mini size spark plug, the contact pin wont contact our baby sized s-plugs contact tip. Also the spark generator is VERY weak.

murchak

I see. Thanks for letting me know. I could cancel before they process and ship. Is it worth having that tester in general? I have a honda pilot, a riding mower, a go kart all of which have spark plugs that might need testing someday. Is there a better tester that could also test Mercedes plugs?

S-Prihadi

Well, in order for us to know our s-plugs are good, we need to equal the firing power of our COP.
However, there are differences in firing when and if there is fuel ( hydrocarbon ) , vs dry air no fuel spark.
It can be a general guidance that Autotool spark-plug tester, but for very accurate diagnostic maybe not so useful.

For s-plugs I simply get MB original ones, easier and I replaced plugs only at soonest 20,000KM which is equal to 4 years for me if I use my car well.
These 2 years I been logging only 1,200KM per year, so if I do replace my spark-plugs , it is to simply prevent thread seizure.
I am at 37,000KM today and 2nd s-plugs set was at 30K ish KM ago, 4 years old. 1st one was at 10,000KM but 4 years old too, that is when I first bought the car.

ADD : i do align my plugs as per MB WIS and in fact on one of the bank, I have to make custom thickness copper washer to be able to set s-plugs alignment in spec

murchak

I picked up a Bosch double iridium plug (the only choice available) from Oreilly’s and installed it in cyl2. The car idles smoothly with no jitters. It drives well. Hopefully this addressed the issue. Fingers crossed.

Westlotorn

Your fuel trims are pretty close, not far off perfect so your engine is running pretty well but have the misfire sometimes. I just worked two hard months fixing the misfires on my friends car and became very familiar with the M276. I also drive one.
One thing not discussed so far but I have witnessed twice. The intake manifold on this car can be difficult to install due to the rubber vacuum line at the very back up against the fire wall. I admit that not once but twice I damaged or let one of the intake manifold gaskets get out of place and both times it caused misfire issues not related to my #1 misfires. There are only 4 bolts and a few wire connections, 5 I think, two hoses attach at the front of the manifold by the throttle body and the manifold can be lifted off for inspection. Don’t be surprised if some gaskets stay on the block and some come off with the manifold. That is normal. On install place all 6 gaskets properly on the intake manifold. I started using a thin, 1/8” thick piece of plywood cut to protect the gaskets while I set the manifold on the board till I had the rear vacuum line hooked up again. With all the practice I had pulling and re installing the intake would not take 15 minutes going slow and being careful. Worth a check to verify all 6 gaskets are sealing on the. Manifold. I would not suggest the check if I had not seen the misfires myself twice due to this.

ChrisHimself

yeah auto parts stores are great for that random science experiment lol

2014 E350 yeah?
https://www.rockauto.com/en/moreinfo...=7212&jsn=1632

Be sure to index/torque them properly so they're facing the correct way.

Westlotorn

My plugs are not indexed and I have no misfires. I do know about Indexing, Racers used to do that 30 years ago. The only way I could see indexing in these cars would be to have a slew of copper washers available to vary the thickness which would change the location of the plug gap. I assume you face the gap towards the Injector spray? In the old days we faced the gap towards the intake valve where where the Air and fuel came from. The plug would need to be marked or the extension you use marked to install the plug so you could watch where the plug gap is facing as you tighten it down. You guys that have indexed please share your tips for doing this job in a reasonable amount of time. I have run Bosch, Champion and NGK with no issues. I try and stick with a company that makes spark plugs. Mercedes does not make spark plugs they buy them. I like the Iridium plugs they can last 200,000 miles with no wear on the iridium tips so the gap stays the same. They also spark with less voltage than a platinum spark plug so a much improved but pricey choice.

ChrisHimself

Oh hey it hasn't been mentioned in this thread so far, the OE plug is a double iridium by Bosch. If someone digs this thread up later just know it's BOSCH ZR6SII3320

The reason people are bringing up doubleplats is because MB has been using Bosch/NGK double plats for like 30 years now. Newer cars with indexed plugs that fire hot are these double iridiums that are out now.

i'm just goin off what i do for the M276/M278/M157 engines which use the exact same equipment. I treat all Mercedes with the same care, AMG or not. All plugs get indexed. The left side is kind of a pain in the *** on the M276 cars cuz of the bracket.

you just torque em lol. 17ftlbs and theyll be alright. When I mean index it's not for performance the plug just wants to be facing a certain way in these engines and the head/plug/washer all line it up at 17ftlbs correctly.

murchak

I neither torqued nor indexed the plug. I have a fairly good CDI torque wrench but I doubt it’s so accurate such that 17ft-lb would ensure that the gap is facing the injector. I suppose for a race car such fine tuning makes sense and one would really need precise instruments and skills/experience to do so. I don’t think I can be convinced that such fine tuning can be achieved with DIY tools. I’m just happy the idle is smooth and the car runs fine.

S-Prihadi

The whole indexing thing for spark plug is a joke, from the perspective of my engine M276.820 3.0 TT...........where MB themselves did not machine the s-plugs female thread accurately on Bank 2,
to produce result to the 45 degrees window allowed by MB at the specified torque.

I have a thread on it years ago where I marked my s-plugs and torque down to the recommended torque.

If one think that when following MB torque spec ( without using marker to verify ) and hence your s-plug will be ALWAYS be within that 45 degrees window on ALL engines .... I want to smoke what you are smokin

ChrisHimself

i didn't even know why we indexed the plug, I was just told it was kind of a thing to do and a liability thing on all installed parts in general. i actually had no idea it didn't matter that much..

well time to back out all my M157 plugs out a lil bit just to mess with MB

Westlotorn

With Direct Injection and fuel pressures of 200 bar, (200 x 14.7 = 2,940 lbs pressure) who knows how important indexing is. We in the aftermarket are still learning about direct injected. I am sure the factory has a very good idea of what is needed and they indexed. To be honest I did not even think about indexing the plugs when I changed them in my E350, if I had read a little in advance of that I would have checked indexing on the install. Currently it still runs flawless and the MPG is very good so it fires well. I used Bosch iridiums maybe I was just lucky and they are close enough.

S-Prihadi

Plugs indexing is very important if the engine can do Stratified combustion and is a spray guided type : Our GDI is a spray guided type , M276 is.
https://www.sciencedirect.com/scienc...60544216303097
and
https://core.ac.uk/download/pdf/40043567.pdf
and
https://www.greencarcongress.com/200...esbenz_pr.html
and
https://www.motor1.com/news/63926/me...ection-engine/


I believe if one's engine is the stratified version, it will have special additional Nox sensors and the data card will show it .
In Europe it is more common I think, in USA I don't know.

CaliBenzDriver

In the US, the rullings of the EPA clean-air guys follow the industry hand outs.
Europe is where stratified injection is used because it doesn't matter, they are in love with "clean" turbo diesel cars !

The way I've understood this is... US has the basic non-stratified GDI version.

+++++ misfire while scanning CGW...
Today I was scanning M276 while waiting inline at the gas station - Amazingly I witnessed how the stupid CGW CAN CAUSE ECU MISFIRE.. ouch!!
NOTHING should be able to impact the precise engine timings but basic testing shows otherwise - This confirms: our best interest is to prevent CAN BOTTLENECKS for good engine timings

Going for DTC-FREE network buses:
ToDoList: shield my CAN lines from bus bar to RFK possibly real soon. I want to see if that helps clean up RFK CAN faults. I think long bus-lines of twisted pairs hugging noisy power should benefit.
✌️
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