Bad tune or?? ;-/
 

Hi Guys, i yesterday got a Tune for my W204 C63, mods are BMC airfilters, resonator delete and sec cat delete. My car gained almost 80 HP from the tune and the throttle response also got improved alot so overall im very happy with the tune! BUT i have now discovered that when im driving with 60-70 MPH at 1800-2200 RPM just driving steady speed the car can quickly hesitate / cutting for a split second and then drive normally again.. when driven hard and engine temps getting hotter the car does it more offen but at same RPMS ( 1800-2200 a quick hesitation / feels like a fuel cut or something like that...

MY tuner which ran the car on dyno and are known to do great ECU flashes tells me that he think spark plugs could be the issue, that i should put a new set colder plugs in the car? what do you think plugs are 20.000 miles old. My friend / mechanic think that its a glitch in the ecu file, hopefully my car will not break anything with this issue?

Thanks!

Do Plugs. Very common

check the intake mani gasket. mine did that with a tune when the gasket was bad and leaking but it never threw a CEL. might be O2 sensors too. how many miles on those? mine chugged like that with bad O2 sensors.

I had that issue with a tune. Switched to a different tune and never had the issue again. It isn’t the plugs.

Try the same everything, but with traction control off, see if the momentary power cut is still there.

Which tune is it?

If you did not have issue before the tune then it is the tune.

Drop your plug gap to 22, you will find it helps, you might need to change them out more often.

That’s beyond incorrect to do. This isn’t an n54. The tune is the issue not the plugs. I had a similar issue with MC-Chip Tune. Switched over too Weistec never had an issue.

I don’t agree with you comment, I have a personal friend who works at Renntech. I run my plugs at 22. I have not had one issue. I will say it sounds like you need a better tune that’s built for Mercedes AMG.

I don’t need a tune. My car runs fine. Gapping plugs at .22 on a N/A car is odd since stock gap is .40

just cause he works at Renntech doesn’t mean he knows what he’s talking... just like having a drivers license doesn’t mean you know how to drive.

Well maybe my AMG tech and the tech at Renntech is not as smart as you. All my toys have some form of mods and tunes on some very expensive toys. Sounds like you just don’t know the right people.

I also will add you most likely don’t run 104 gt plus either with full mods. My toys are not daily’s either.

Just what I thought, just two different levels of people, just what to expect from those like you on that different level. The funny thing is, it’s just what’s expected from those on that level which now include you. Awesome thanks for letting me laugh at you.

Are you supercharged? If not, and you're having to run such narrow plug gaps, then your ignition system isn't up to snuff in some form. That's ridiculously tight on a n/a car and is most likely costing you power. For comparison, I run a .28 gap on a 600 hp ttrs that's blowing 30 psi and .40 gap on the c63 with a 100 shot.

Finally someone one that knows what they are talking about 👏🏻

+1 running a 22 gap on a NA 63 is totally unnecessary unless something else is wrong. In fact, it’s only hurting performance vs a 40 gap. Bad advice. :crazy:

This is common for said user.

So I’m just going to put this to rest. I run exactly what I say with no issues. I also have great techs to work on my p31 w 12k on the odometer. I run a complete set CNC ported heads/w Cams, Weistec oil separator, 82 mm throttle body’s, Capristo valved Exaust, MBH Headers, RENNtech air intake, Agency power under drive, although I am considering taking the under drive off, Weistec built transmission, I also have a custom Renntech ECU tune for 93 plus octane tuned for my car after all the mods were installed, I also only run Sunoco 104 gt plus, I’ve had some of the best work on my car period, any day you make it to the NW seeing is believing send an IM. I like to see people eat their words.

https://cimg8.ibsrv.net/gimg/www.mbw...d1189ea0f.jpeg

Just trying to help. Of course the car will run fine with that tight gap, it'll still ignite the mixture, but you'll get better burn and more complete combustion running the widest gap you can get away with. You said yourself that they told you the plugs would need to be changed more frequently. You know why that is? It's because your not getting a full ignition, which is causing unburnt fuel to build up on the plugs, necessitating early replacement. The only reason for a tight gap is to prevent the spark from blowing out under high cylinder pressures, which, being normally aspirated, isn't a real issue for you. Your doing yourself a disservice running those gaps. Like I said, I'm running 30 psi, pushing 600+ hp through 5 cylinders, not 8, along with 1000 ml/m of watermeth, and still don't have issues at a .028. My cylinder pressures are much, much higher than yours yet no problems. So either your ignition system isn't up to the task or you're getting bad advice. Do yourself a favor and replace your plugs and leave them at factory gap.