Scanner 101 ... question:
did you or not reset the ECU before moving coil ?

I am going to guess you did not... so the ECU computed under mixed conditions with all pre-existing data
thus based on that, your ECU came up with a bit of a non-sense ...

> TO DO:
Reset ECU FAULTS using scanner
drive then scan again
Repeat cycle
✌️

 

I have a little BlueDriver scanner. I swapped the coils then used the scanner to clear the codes. The used the scanner to read check engine light codes.
is clearing the codes using the scanner the same thing as “resetting the ECU?”

So before I touch anything today, I’ll reset the ECU but turning the key to ON but leaving the engine off. Then I’ll use the scanner to clear all codes, then turn the car on to see what check engine lights will come on. Then I’ll repeat the procedure to clear codes, then swap the coils then read check engine lights

 

Okay I cleared the codes properly with key ON and engine OFF. Then I turned on the car, no check engine light, so I let it idle for a few min, then drove for several min (engine temp around 85-90) and came back. I still feel the jitter, but not sure why the check engine light did not come on after the engine being on for more than 10 min. Below is a screenshot of some live data.
I’m sure sooner or later the check engine light will come on and then I’ll read the code. Meanwhile, what other live data is relevant to look at so I can screenshot and post it?

 

> Recap to this point:
Your questionable COP#2 is now located in Cyl#1 and causing misfire code in Cyl#1 only.
No more code in Cyl#2, yes?


> Boot or coil ? :
If Cyl#1 only misfire is true, your testing has proven your misfire is spark related.

I would then change all rubber boots to see if that's enough to fix your misfire
or throw in 1x exact-same new MB coil.


> Lean Trims :
Once you no longer have any engine code, your fuel trim numbers will become meaningful measurements.
Now LTFT are LEAN but that's skewed by bad cylinder ignition plus intake sensor fault.

 

As I said above, I initially only had P0302. Then I moved COP from cylinder 1 to cylinder 2 and COP from cylinder 2 to cylinder 1. I did this without first properly erasing the ECU’s error code (P0302). As a result I got the following three new codes (in addition to P0302): P0300, P0301, and P0113.
So I went ahead and erased all codes the right way with the key in ON position and with the engine OFF. Now I have no error codes and am waiting for the engine check light to come on and then I’ll connect my scanner and see what error code(s) shows up. I started the car and idled for 5 min and drove for 5-7 minutes but no light came on even though I clearly feel the jitter every 4-5 seconds when the car is idling. When driving it’s harder to notice anything. I’ll post an update soon.

 

check your plugs, make sure nothing is fouled, eroded, and torqued to spec

replace the rubber boots, theres an NGK kit on Rockauto which solved my issues

i doubt it's the coil it's an MB genuine part, but if you want to buy a couple Bosch coils from Rockauto to play with, maybe we might stumble onto something.

I've read the misfire nightmare thread and I shudder at the idea of buying a newer MB at this point

 

I personally think all new cars with more than 10 modules (nearly all of them do) are prone to these issues. Grounding issues are the Achilles heel of modern vehicles since we are mixing electronics, electricals, software, and low-cost manufacturing into a single product. No wonder parts for aviation cost that much with all the required certifications. Recall the 90's with tens of computer manufacturers, and now we are down to just a reliable few. It is not child's play to produce reliable electronics with reliable software. Those hanging modules, and reset procedures are analogous to "laptop reboot after the blue screen of death" it took 2+ decades to get to Windows 10 and still not where we should be. Even a fruit-named phone manufacturer worth billions could not make right on time, and it is now part of the technology history/museum.

 

"As I said above...." - Apologies, I don't mean to make you repeat yourself

> Troubleshooting tip:
When testing questionable parts swap.. try to make sense of the test results you're observing.

That way we can try to help you skip forward without using a parts canon.

The very first step with misfires is to have a proven good ignition to rely on. The modern lean engines are always kept borderline misfiring. It doesn't take much ECU upset to cause fish-bite misfire.

 

Thank you CaliBenzDriver. Good suggestion.
I’m fairly certain that my coil from cylinder #3 is good and is located in bank 1. I prefer not to take out or touch cylinders 4,5,6. Sooner or later the check engine light is going to come on, and I will scan to see what error code I get. I will report here my observations and the proceed accordingly.
I assume the proper way to remove the ignition coil long with its boot is to use a pair of hose grip pliers at the base of the boot and gently putting it out. Is this correct? Is there a convenient way to make some measurements on the coil/boot to determine it’s faulty or not?

 

I like this video from Sr Leigh.. I have those pliers


However, ingenuity is always around.. You can gently pull with a rope.. Let me find you the video.

UPDATE:
Sorry, I cannot remember where I saw the "improvised coil puller", but here is the idea ( https://mbworld.org/forums/c-class-w...ml#post7490682). The idea is to get a piece of rope, and piece of wood about your hand long (say a 2x2x5), drill two holes on either end and fish out the rope on both sides, and knot them. Now you can pull the coil once you lasso the coil tab and pull firmly.

Found it , but it was a write up, not a video.

 

Haha I love videos from Sr. Leigh! I followed his video on brake fluid bleeding a few days ago. Wondering if I should somehow get the SD Connect 4 with Xentry. Many people here suggest contacting benzninja. Would a tool like XTool d8 be a good choice? I also have a Honda Pilot and want a good scanner that could work for both cars.

 

yeah i'm still learning this but usually you have to reset codes anytime things have been changed, the car will store that code even if the cyl happens to be fixed.

I reckon the coil springs inside the boots are corroded as mine were. I'm really rooting for you that it becomes a simple fix here!

 

I turned on the car, idled for a few min, driving for 10 min and idling for another 5 min. Still no check engine light. But again at idle, every 4-7 seconds I feel a little jitter. I called the local Mercedes dealership and they do sell the ignition coil connector/boot for around either $19 or $26 depending on my exact ignition coil make/model. I’ll probably go over there today and buy a couple of connectors.
Why hasn’t the check engine light come on yet? Any guesses?

 

The software may have count-up / count-down logic for triggering the misfire indication and you aren't reaching the count threshold to trigger it.

 

Is there a reliable way to test the ignition coil and the connector? I took the ignition coil out and removed the connector. Visually I don’t see any issue. They look fine. No cracks in the rubber part, the inside spring and connection parts look like new. I don’t see any physical damage. Wondering if I should buy a spark plug tester and use that to see if coil pack is working or not.

 

The boot can look like new. The question is if it is arching.

Since you have tested the misfire moves with the coil, it is the coil unit. The question is if you want to narrow it down to the boot, or the coil electricals. Because of my ignorance/lack of confidence with electricals, I would replace the coil. If the jitters you observe go away, it is your decision to get the 5 extra coils and open Pandora's box. If it does not go away, well we got another misfire mystery situation.

Why do I say Pandora's box? How did the coil got damaged? Mileage? defective? or mistreated during the spark plug change, or air filter change?

You can see I look after 4 different vehicles, all of them are on original coils. Only one has a DTC code (W211 for the intake manifold) w/o CEL light. Two @90K, and two passed 120K. I think MB coils are bulletproof.

 

I ordered a Lisle spark plug tester from Amazon for like $10. It should come tomorrow. I want to make sure both cylinder 1 and cylinder 2 ignition coils and spark plugs work. I’ll post my findings sometime tomorrow or on the weekend

 

Juan, you have this perfectly summarized.


You gotta have good spark for a chance to get timely mixture ignition but these days it's no longer enough.


> DIRTY 02/L SENSORS:
After that replace the amazing oil-leaking PCV and both old upstream Lambda sensors.
The engine conveniently burning gallons of its own oil builds up a carbon layer directly on the exhaust sensors.
The dirty wideband O2 sensors drive the ECU data learning from historical combustions.
The outcome is the ECU compute a (lean) fuel mixture that can hardly get fired right. ​​​​​​

Last you want to reset the ECU so it can relearn data from combustions trimmed close to 14:1 neutral.


> UNEVEN TIMINGS :
When the load applied to the engine is irregular uneven the learned timing corrections are unable to be exactly timed to the hundreds of microseconds.

The tics from the CKP are doctored by the ECU to trigger injection and spark a few millseconds later. This is where a busy CAN latency can affect the ECU responsiveness (hick-ups type misfires) - "Theoretically everything is beautiful" : a solderless module on a chassis CAN storming the Gateway should not affect timing responsiveness... but it does exactly that. (for the wise men: fix faults on your VIP Modules with top considerations).

In that context there are multiple factors that can mess up smooth timings: junk tensioners are my favorite here. Split engine mounts, tranny mount.

All of this is a bit vicious because it happens very gradually with bad cumulative effects... 1+1=3

Ex: when a weak spark from a cracked carbon track inside boot meats with a lean mixture from the dirty O2 couple milliseconds after calculated prime timing advance, you get incomplete combustion that lands a lean injection during next compression stroke.
You just got a lean misfire condition.
If this keeps up longer... the ECU will stop injecting the cylinder with poor contribution.


> Sensing Contribution & Misfires :
The ECU keeps track of the CKP tics super closely to figure if a flywheel tic "shows up 5 micro seconds late", something caused the latency.
These timings are well scrutinized and ultra precise with very slim error margins.
When a cylinder tics late its a poor contributor as it gets worse it gradually progresses into misfires territory.


> LOL :
What's funny is when people finally realize injectors are not spraying enough fuel, they start messing with the parts-canon (plugs, coils, injectrs, pumps, filters, ECU, ...) without any lasting improvements

The right way is to consider the combustion is controlled by Bosch software based on sensors data. Zero luck is involved for the code to perform as expected.

Many thanks to all sharp minds and good friends dedicated to this craft. Everyone brings his own perspective.

 

Since I am waiting for the spark plug tester, I decided to clean the throttle body. Senior Leigh has an excellent YouTube video on this. I’m following his method. Here are the before picture

 

Since the throttle body is out, how do clean all that gunk and oil that you see in the picture below?
also after the cleaning, I noticed that Senior Leigh in his video started the Xentry software to reset the throttle body valve angles something about adaptation values reset. Is this something I need to do? I don’t have Xentry

 

Quick update:

I had cleared the codes, then after driving a few times, the check engine light came back on with P0301. So I cleared the code again, moved the ignition coil boot from cylinder 1 to 2, and vice versa. After driving a few times, the check engine light refuses to come on. I want to know if it’s just the boot that’s bad or the coil. The car clearly still jitters at idle. Also, I tried to briefly rev up at idle and it won’t go above 4500 rpm. I did it a couple of times, and same thing. The idle rpm is 600. When I am driving, I can clearly push the rpm above 4500 without noticing any loss of power.

 

Update 2:

Last time I moved the coil boot from cyl1 to cyl2 and although the check engine light didn't come one, I could still read the error code (under pending, and not confirmed) to be P0301. So boot not the problem. Then I cleared the pending code, and moved the coil from cyl1 to cyl2 and again P0301 came up as pending (check engine light still not on).
So I cleared the pending P0301 code, and moved spark plug from cyl1 to cyl2, and this evening was able to see the pending code as P0302. This is the first time I see some "clear" evidence of the pending error code that followed the spark plug. I am fairly certain (not 100%) that the spark plug is the problem. All my spark plugs
are genuine Mercedes plugs with the Mercedes logo. Do I have to buy a new Mercedes plug ($28 on FCPEuro and about the same or a little more at the local dealership), or can I just get a Bosch or NGK from Autozone? Bosch Double Iridium Spark Plug ZR6SII3320 ($16.99) or NGK Laser Iridium Spark Plug 95875 ($19.99)?

Thanks

 

MB plug is a Bosch. Over the years I've learned that even if x OEM brand makes the part for MB, the OEM part is often different and worse. This applied to batteries, filters, I think I can excuse spark plugs though. Cross reference the FCP Euro part number with rockauto to find what you're looking for. AutohausAZ and EEuroparts are great sites too.

Bosch/NGK are fine. I would recommend professionally that you use Bosch Double Plats that are for the car in the specific gap if you want to do the job once if youre not in the mood for a science experiment. The rewards of playing with plugs is really not worth it given the labor involved and how much you've been through.

If you do want to do a science experiement, Iridiums are ok. I use NGK Rutheniums in 2 of my cars. I just wanted to see if it'd work, but I'm weird and I like playing around with the cars. The reward for the risk of the car misfiring with whatever goofy plug installed, is I might not have to change the plugs again and the car runs in peak form longer. Maybe.

 

Thanks Chris. At this point I have zero interest or patience in experimenting lol. I just want to buy the right plug and be done. BTW, I learned today that spark plugs could misfire at low RPMs but be okay at higher RPMs. This could explain why at idle I could feel a little jitter ever few seconds but when I drive the car, I don’t notice any issues, no loss of power etc just smooth. I was looking at Autool spark plug testers on YouTube and really like them. They allow you to take the plugs out of the car and test them at different RPMs without having to use the car’s ignition coils. You simply insert the plugs inside dedicated holes in the Autool tester and plug the power and there’s a little dial that mimics a car’s RPM. You can easily see the sparks of the plugs are good. Ordered one for $27 and will receive Wednesday. Meanwhile I’ll just get the Bosch double platinum or iridium (a few bucks more) and try it.

 

While we are dealing with double iridium pin misfires, I can contribute my experience with stuby platinum that fire better than pin-head Iridium on my DD.

I'll be happy to replace my original MB plugs with stuby dual platinum given equal specs... temp range - - We know MB likes to run these engines hots, so we can X-Ref. a plug with cooler tip for self-igniting protection.