Davidkuo0330

Congrats on finding the problem. I don't know how many miles are on your current plugs, but since you have a tune. I would buy colder plugs and have your dealer gap it and install it for free and them them you think it also has to do with your old plugs.

Good luck.

OrientBlue3

I wouldn't doubt it. That's why I asked them to check the plugs. I will have them keep the car an extra day to cold start it and make sure the problem is fixed. I wouldn't mind if they applied the service bulletin software but I think since they, as of now, thing the bad gauge is the problem, are going down that route first.

They did say the bad temp gauge was causing "other" problems, so I'm waiting to have more clarity on what those are. I should have an update later today.

OrientBlue3

Hi all, just an update. Got the car back for 2 days and it went back immediately because they did not fix several of the things I asked for.

What they did fix was the cold start bucking. What they didn't fix was the idle spike that pops up from time to time in reverse and in drive with my foot on the brake at a light on a cold motor. There were no misfire codes, so they did not change the plugs. I'm tempted to send my ECU back to Eurocharged and have them take a look. Sure, the easy answer is blame it on the plugs and say change those, but I'd prefer to avoid having to spend $500 if possible, especially when I'm not getting misfit codes. I did buy a code reader, so I can be prepared if a CEL comes on in the future.

Anyone else get these idle spikes/blips? I've tried to record it but happens so fast that I can't get my phone out fast enough.

kponti

Well keep trying, and when all else fails, change your plugs (hopefully you regap them first) and come back and tell us your car is fixed

2500 plus miles, no sign of misfire, idle inconsistencies, all around weirdness anymore

chiromikey

I get the same symptoms you describe and my car is stock at the moment. I don't feel like it's an rpm spike as much as I think it's the trans disengaging then reengaging...but it's hard to tell since it neve does it when I'm paying attention. It's at the dealer now so we'll see what they come up with...

OrientBlue3

Anyone have the OEM spark plug part number and the lowest price to find them online?

PeterUbers

I get a little stutter in the car idling forward with my foot gently on the brake occasionally but agree with Mike this is the clutch behavior

Georgee6086

Mine also has the occasional idle stumble/serge (maybe 50rpm max) but I'm not worried one bit. I think almost every mercedes I've owned has done this and I've had many over the past 20 years. I've never owned a Mercedes that idles like a lexus.

chiromikey

Well, I picked up the car this afternoon and feel it's too soon to make the call...but so far not a single symptom where I'd typically have at least 2 or 3 in an afternoon. I had my B service done which includes trans and diff flush and I also had motor and trans mounts replaced so that could possibly have helped but they performed a TCU update which they claim cured the symptoms. I'll report back in a few days...

OrientBlue3

I'm picking up mine today. They replaced my Weistec Bosch Silver plugs (which were gapped at OEM specs, pretty sure this caused the problems) with new OEM gapped at .022 (they charged an extra 1/2 hour labor to change the gapping).

One unexpected side effect was my car failed the emissions test due to my Eurocharged tune. I do have cats but they were getting an O2 sensor error. I had this exact same issue with my EC v4 tune on my W204 C63 last year. The dealer did a software update, overwrote the flash and it passed inspection. I will send it back to EC for a reflash here shortly and then I can determine if the $600 spark plug change was all worth it!

Not looking forward to driving the car stock for a few weeks until I can get a loaner!

kponti

So the regapped spark plugs fixed the problem? Is it confirmed or you haven't tried it out yet?

OrientBlue3

Lots of paperwork issues. I won't get the car back until tomorrow now. I was also told they never actually did the software update since the car is now out of warranty they would have had to charge for that. So I still have the tune (just can't pass inspection due to a glitch in the tune) and will be able to find out if the new plugs/gapping has fixed the car tomorrow. I will report back! ECU is going back to EC in 2 weeks when I can get a loaner car to drive around for 3 days while they re-flash it and work out this O2 sensor issue. Weird that this is the 2nd time this has happened to me with an EC tune on 2 different cars.

chiromikey

First full day of driving with the TCU update and zero bucking or idle issues. I'm still skeptical but very excited!

PeterUbers

Very nice

OrientBlue3

The spark plugs did not solve my idle spike. Got the car back yesterday and put it in reverse as I left work with my foot still on the brake and the idle revved so high (two individual revs actually) I would have probably done a reverse burnout if I didn't have my foot fully on the brake. Since the ECU needs to be re-flashed by EC to fix my inspection issues, I will have them look at the logs to see if they can catch anything that might be causing this.

kponti

Being in Texas, I hate to say it but the software glitch that is causing you not to pass inspection may not be solved unless you went back to the stock downpipes and retuned for that. I am guessing you are running catless pipes now???

OrientBlue3

Nope. I have cats. I've never not had cats. Again, I had this exact same issue with my W204 C63 and EC's flash last year. Says "O2 Sensor" and "Heated O2" are in "NOT READY" status. I sent my ECU back to EC and they did something to fix it and it passed when I took it back. Hopefully that will be the case again with my CLS63 now.

PeterUbers

What does EC Charge for a reflash?

kponti

Oh then that should be a easy fix. They may have a standard tune that turns off the post catalytic convertor sensors (usually known as sensor 2s). When turned off with a tune, it stays showing a not ready signal.
I had EC keep mine on and turn it off with Star myself and passed inspection with no problems.

OrientBlue3

It's free. Just have to have the car down for 3 days. Gotta wait for someone to let me borrow a car. lol.

Yea, just funny it happened twice in a row on 2 cars. I told them ahead of time I had cats. Definitely makes sense they could have given me the catless tune. Though. I will have a loan car set up in about 10 days and then I will send it back. Hopefully they can check the A/F log and other data to see what the deal is with the idle spiking. Kinda sucks that I spent $500 on new plugs and it didn't fix the problem but at least I know these are gapped right now. In the past, I knew I needed upgraded plugs but somehow missed that I needed to reduce the gapping from OEM and thus had the upgraded plugs installed at .031 instead of .022.

OrientBlue3

Hi all,

Just adding an update.

I'm still having the bucking issues despite replacing my Weistec Bosch plugs (gapped stock instead of at .022) and replaced them with new OEM plugs gapped at .022.

This mainly occurs on a cold motor below operating temp. Usually between 80-120F. I especially see it upon cold start when I first go into reverse and I ride the brake to back out. The idle will jump like my foot is on the pedal and I'm blipping the throttle. Obviously, my foot is not even on the gas at all. It's very strange. From there, it happens again randomly during my first few stops, pulling out of my gated garage, stoplights, etc. Once the motor warms up, it goes away.

I sent the ECU back to Eurocharged but I don't believe they checked any of the data. I had sent it back because the DECAT was causing me not to pass my inspection, so they fixed that and sent it back.

Anyone else have an idea as to what this can be? Obviously super annoying when I start the car every day. I've done several TCU resets and this does not fix the problem. I only use 93 octane. Kind of frustrating knowing I spent $500 to replace the plugs and this was not even the issue.

Thanks in advance!

kponti

Any codes?

Mike450

Gapping the spark plugs down is to avoid spark blowout under wot from the increased boost. The change in heat range from OEM is to avoid detonation.

Your idle issues sound tune related, TCM or engine, certainly not plug related. Might want to reinstall OEM tune and see if it clears up the issue.

Good luck.

OrientBlue3

Only CEL I had was due to the bad temp gauge. I will run my scanner just to see if I get any codes but I don't know if I will because I have no CEL.

OrientBlue3

Correct on the plugs.

I have the standard EC tune. Ideally I would like EC to take a deeper dive for me but they claim they've never had this happen before and blamed the plugs or that I needed to get a dealer software update. I did both and still have the issue. The problem for me is, I don't have an extra car readily available to just send them my ECU for a few days.

Like I was saying, fortunately it's only a cold motor thing but it's definitely getting annoying.

Unfortunately for me, my warranty has expired during this process. I'm hoping any potential TCM or motor problems could be covered under the fact that I did open a ticket with the deal while I was still under warranty.