Rickcross

Car: 18’ C43 (Eurocharged stage 1)
Codes: p0300-p0306 (and all in between)
When?: Only with pedal to floor/full throttle. Drives %100 fine when just cruising even for long distance.
Repairs: replaced all plugs 3 times, all coils twice, all fuel injectors, maf and cps sensor

Story:
Drove my c43 for 10-12,000 miles after buying it, drove beautiful %100 perfect. Brought it into Eurocharged to get tuned and new spark plugs and within the hour after tuning it misfired. Owner of the shop said it was normal, but it kept persisting so I brought it in, they said my brand new plugs needed cleaned?. Few weeks down the road I get all new coils, maf sensor, cps sensor, and it’s still doing it. I bring it in and they say it’s the learning computer, reset it, and it does it again after I leave shop. Brought it in yet another time for diagnostic ($180 an hour) and say I need new fuel injectors (quoted at 4k). Get them, and still is misfiring! I bring it to another ec location 5hrs away, they say the first ec shop never installed proper oem plugs or coils, so they did that ($1,100) and it misfired on my way home. I’ve had it diagnosed by Eurocharged 6+ times and I just get parts thrown at my face I’m sick of it. Help what do you guys think, Eurocharged is sending me a new check valve to try.

its mind blowing how many times Eurocharged has handed me my car back and it’s been “perfectly fine” just to misfire always almost immediately after leaving shop, I’ve begged them to do a proper diagnosis especially with how much money they’ve made me literally waste, and every time it’s the most basic repair to not fix it, I’ve spent well over 5 grand because of misdiagnosis now.

TwoC400s

It's the tune. Ask them to flash it back and get a JB4 if you want more power.

I got lucky and my first tune from EC Houston was pretty good, I did a bunch of 1/4 mile data logging and sent them back the data just to be sure everything was kosher.

They were very nice to offer me an enhanced tune (I guess because I gave them so much real world data), but the instant I loaded the second tune I had massive issues, misfires, hiccups, transmission codes.

I just flashed it back to the first tune that was pretty good, and am using a JB4 on top for additional boost on the top end.

Rickcross

that’s what I’m thinking and hoping that the tune didn’t cause a bigger issue. I drove aggressive for 12k miles pre tune in every situation you could think of, and then when I brought it in to get tuned it misfired within first hour. Why I’m now believing it’s tune related

TwoC400s

Did you get a Bi-directional scan tool?

You should be able to connect it and record logs of it misfiring.

Might be a way to pinpoint what is happening.

Rickcross

Ya I do. Most recent ones were p0300 and p0306 but in past has done other cylinders. Unless you mean actually log it while driving I’m not sure how to do that I got the launch x431 2.0

TwoC400s

Yeah, actually log it while you're driving, you go through the manual select, get to the module that has the bad codes and there should be a live data option.

TwoC400s

One additional thing I want you to try before you lose all hope is maybe find and E85 fuel pump and put 2 gallons in on an empty tank and then fill up.

Or you can try a quality Octane booster like VP Racing Madditive Octanium.

Especially since you are only having the problem at WOT.

MaverickC43

Eurocharged was the way I was thinking I might go, but hate what I’m hearing. Issues can arise obvi, but that customer service SUCKS

where r u located at?

Rickcross

Midwest, just take into consideration I had purchased the c43 with a perfect service record at 47k miles. Drove the car myself for 10-12k miles then got it ec stage 1 tuned, and within the first hour it misfired.

Rickcross

I still have yet to try and run it stock, that’s going to be my first go but first, EC are mailing me a check valve to try hopefully that’s the remedy. If not I’m going stock, and if misfire happens to persist in stock which it never did I am %100 trying your recommendations. Got a big feeling it’s the tune anymore, never dyno’d or nothing.

MBENZTECH

One thing you guys have to understand, is that most of these tuning locations are franchises. So tunes get passed around and copied over and over. I have been a Mercedes Benz specialist for 18 years and I deal with these all the time. So here is what I think is happening, your car is running super rich. So every time they change plugs, it runs good until they get full of carbon due to running too rich. So even if you go back to stock, make sure you check, clean or replace your plugs. I have also ran into internal ecu damage and have replaced ECU's after it gets tuned. If you need advise or assistance, send me a PM.

TwoC400s

I totally agree with your take on all the different "tuners" out there who are really just flashing a file they did zero development on, in this particular case the plugs have been done three times and it misfires within hours, sometimes minutes of the new plugs being installed.

Is it rich? Is it lean? Is the timing too retarded or advanced?

No way to know without data logs.

Rickcross

waiting to log until I get the Check Valve, hopefully today. I believe it’s running lean or rich if my ears serve me right but also I’m kinda of a newbie. You’re right about that,has literally happened within minutes of plugs being changed. The most recent change of spark plugs I did get to run a fairly decent 2 hour stretch before a misfire occurred, doing everything that would cause it before.

Rickcross

Thank you sir, that definitely makes a lot of sense and am leaning towards that the tune (they even admit putting on thousands of vehicles) is causing this misfire. I was thinking the tune has further damaged the plugs because it something that occurred more and more frequently as each misfire happened. My thought was even if they flashed it back to stock last diagnosis, the spark plugs would of already been shot (from probably 10+ misfires) that it would of continued to misfire for that reason. Though the twoc400s is right, it has done it minutes after changing the spark plugs literally. But last change of spark plugs I got about a good 2hr run of hard pulls on the highway before I misfired. Hopefully get some live logs tonight.

Baltistyle

That the shop did not flash it back in the diagnostic process is a problem to read. Unfortunately many tuners standing beliefs are that tunes expose weakness so its normal to have some slight issues or to have to replace some sensors after a tune. Generally codes are very specific and you dont have to change "all" of the coil packs, spark plugs, both turbos, etc. That is a shotgun approach and not appropriate for what you say is happening.

There is only one variable you mentioned that is causing the problem yet the tuner is having you chase your tail. You had no problems or latent pending codes, installed a tune and it all went downhill. Its a bad tune, dont mess up a bunch of other parts or spend more money or time diagnosing the obvious. No need to protect a tuner by not doing proper diagnostics first (meaning reflash to reg tune before one penny was spent).

Sure its true that thousands of these "same" tunes are on cars all across the world and the fact is, it does not work 100% for all of them the same (due to differences in temperature and humidity, and running parameters defined by region) and revisions need to be made.

This is a situation where I really advocate that people have xentry personally and dont waste thousands chasing a shops poor but very expensive diagnostic procedures. Has a TPS or gas pedal been diagnosed? Has a rich or lean condition been diagnosed per MBenztech? Are the plugs fouling if the car is not taken to the misfire range at WOT?

Good Luck

Rickcross

TPS and Gas pedal have not been diagnosed to my knowledge unless that’s apart of xentry diagnosis. I assume the 2nd EC I brought it too has a xentry considering it’s in the 3rd biggest US City but can’t confirm, will ask today. They never were able to pull any codes or errors beyond my p0300-6 codes. I have a pretty nice system as well and all my system monitors check out good, going to use it soon to try and do a live data log of my driving. I have a check valve being sent to me from EC hopefully that’s the solution. If not I’m going stock.

Rickcross

Went back to stock though and everything is running good now been trying my hardest 4+hrs to make it misfire and it won’t

Rickcross

went back to stock today, drive 4+ hours trying my hardest to make it misfire driving wot most the time and it hasn’t misfired once since going stock

Rickcross

went back to stock today. drove 4+ hrs aggressively as possible trying my hardest to make it misfire and it’s been all good.

Rickcross

went back to stock today, drove 4+ hrs as aggressive as possible through the southern Missouri mountains, haven’t been able to make it misfire once and I’ve been trying my hardest

C43HeartBoost

Echo…

Rickcross

Update: went back stock today, drove 8+ hours aggressive trying my hardest to make my c43 misfire but everything’s all good now.

jimmykoutoulas

some people call me weird but I’ll never tune without a dyno. Fuel levels rich lean AFR are very important. Yes you can data log but why is you have the option to tune with a dyno. We all should.