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I have an odd issue with my c43 2017 stage 1 tuned.
I tuned it using hand-held around 18 months ago. Everything was fine in the first year. Then, time to time the vehicle experienced misfire around 2800-3200 RPM when I pushed the accelerator pedal hard.
I asked the tuner to fix this. They sent me another tunes. Last one was really good, even better than the first one, but I still have the misfire issue. Tuner told me they don't want to change the parameters any lower.
They asked me to send a photo from one spark plug and measure the inlet temp.
My question is that am I the only person who has this issue? I searched a lot but couldn't find any similar case on internet.
Not uncommon to need spark plugs more often when running more aggressive tunes. How many mile you have on them?
Ive heard of some changing them as often as each oil change with Meth+E50+lots of boost. Probably overkill unless you only track the car.
The most load on the ignition system would be uphill, high gear, low rpm trying to build boost. Not good for the motor either to lug it like that.
Not uncommon to need spark plugs more often when running more aggressive tunes. How many mile you have on them?
Ive heard of some changing them as often as each oil change with Meth+E50+lots of boost. Probably overkill unless you only track the car.
The most load on the ignition system would be uphill, high gear, low rpm trying to build boost. Not good for the motor either to lug it like that.
Thanks Matthew. It seems you're absolutely right.
misfiring exactly happens uphill, high gear and low rpm in my car! I didn't have this issue before, even after tune.
I have 20k km (12.5k miles) with the replaced spark plugs. I don't track my car. In last service the spark plugs were not changed.
Should I use the OEM spark plugs or you know something better?
OEM, or rather the OEM manufacture (NGK) is the go-to for almost all of the MB 3.0TT motors. Be aware, there is a lot of noise around counterfeit plugs out there. Not sure where you sourced the plugs from (or if your mechanic did). https://ls1tech.com/forums/general-l...ark-plugs.html
I would order a set from a known NGK supplier or if you want to pay more for the ones with the MB star on them, the dealership.
Check the gap, change them out and see how the car does.
OEM, or rather the OEM manufacture (NGK) is the go-to for almost all of the MB 3.0TT motors. Be aware, there is a lot of noise around counterfeit plugs out there. Not sure where you sourced the plugs from (or if your mechanic did). https://ls1tech.com/forums/general-l...ark-plugs.html
I would order a set from a known NGK supplier or if you want to pay more for the ones with the MB star on them, the dealership.
Check the gap, change them out and see how the car does.
Thanks a lot Matthew, I do appreciate your help.
Will get them from the dealership and post the result here.
Sparkplugs on the V6 is easily accessible. At $10 per piece, I would replace them again even if your last replacement was 20k miles ago. If it stops misfiring for $60, that's no brainer.
Sparkplugs on the V6 is easily accessible. At $10 per piece, I would replace them again even if your last replacement was 20k miles ago. If it stops misfiring for $60, that's no brainer.
You're right. It isn't worth to put the engine at risk because of an easy replaceable item. I bought a set of Merc's spark plugs and install them today. However, they were not as cheap as 60. I paid 230 AUD.
Good question, but we know that is going to open a can of worms these days! It does sound as simple as a faulty spark plug (s). NGK is the way to go and go with the stock gap as suggested above, unless advised by your tuner. Good luck!
Nobody else is aware that Mercedes changed spark plugs for these cars? They use bosch now since a few years ago, so don't buy them at the dealership or you'll end up with plugs that are 2 steps hotter. Since you're tuned I recommend to stick with original ngk plugs, I got mine from fcp euro.
Last edited by BayAreaAMG; 06-15-2021 at 01:57 PM.
Good question, but we know that is going to open a can of worms these days! It does sound as simple as a faulty spark plug (s). NGK is the way to go and go with the stock gap as suggested above, unless advised by your tuner. Good luck!
You're right, I didn't what to open the can! I don't want to blame the tuner now. The tune worked perfectly for more than a year. They even sent me multiple tunes for free and quickly to see if the problem is the octane of fuel. The last tune made it better but didn't solve it completely.
I have a new set of plugs and hopefully tomorrow I'll have time to take the vehicle to a shop to replace them.
Just, in the service manual, the gap is 0.8mm. I asked tuner, he said this is fine.
But 0.028 is around 0.7mm. I'm a bit confused now.
Nobody else is aware that Mercedes changed spark plugs for these cars? They use bosch now since a few years ago, so don't buy them at the dealership or you'll end up with plugs that are 2 steps hotter. Since you're tuned I recommend to stick with original ngk plugs, I got mine from fcp euro.
Are you sure about this figure? Service manual has stated 0.8mm which is greater in comparison with 0.028" = 0.7mm
TIA
0.028" is the gap of the NGK NGK-95875 which is for the C400/450/43.
I have not seen where MB switched suppliers of plugs, but wouldnt surprise me. I would be surprised if they went with a hotter heat range given the newer C43 runs more boost and heat.
Bosch site lists 0.7mm for gap of their plug for our motor.
The CLA45 runs the same plugs as us, they have had a similar discussion with service sites not agreeing. https://www.mercedescla.org/threads/...lug-gap.39526/
FWIW, i would not widen the gap if the ones from MB come at 0.028"
0.028" is the gap of the NGK NGK-95875 which is for the C400/450/43.
I have not seen where MB switched suppliers of plugs, but wouldnt surprise me. I would be surprised if they went with a hotter heat range given the newer C43 runs more boost and heat.
Bosch site lists 0.7mm for gap of their plug for our motor.
The CLA45 runs the same plugs as us, they have had a similar discussion with service sites not agreeing. https://www.mercedescla.org/threads/...lug-gap.39526/
FWIW, i would not widen the gap if the ones from MB come at 0.028"
The more I read, including what you said and the posted link, the more I convince that your figure is correct, the gap is 0.028"
- The ones which I purchased are Bosch. Its gap is written in all websites 0.028"
- Service manual figure, 0.032", is for NGK (written in a table in the manual)
- I have tuned, so more pressre and fuel, so the smaller gap the better
- I have the knocking issue which is one of the known consequences of excessive gap
- I tuned the car exactly after the service including plugs change. The gap become greater over time and the knocking issue appeared.
- There is only one video on YouTube regarding the plug change for C43. The gap written on the plug pack is 0.028"
Hopefully tomorrow I can take the car to the shop and replace them. Will post the results here for others' reference.
I first saw this service bulletin in WIS. I needed to do my plugs in January so I went to the dealership and gave my VIN, asked for one spark plug. Opened it up and sure enough it was the bosch plug. I don't know if mb is building the engine from the factory with these plugs but they're definitely using them for service now.
Service update from WIS
The dealership plugs are now BOSCH V6S113328 (BOSCH 7434)
The original NGK are SILZKFR8D7S (NGK-95875)
The two are identical in all specifications except one, the heat range. The BOSCH have a heat range of 6 by their standards, and the NGK are a 8 by their standards
This was also confirmed by another person who I believe might not be on this forum.
Last edited by BayAreaAMG; 06-16-2021 at 12:00 PM.
I first saw this service bulletin in WIS. I needed to do my plugs in January so I went to the dealership and gave my VIN, asked for one spark plug. Opened it up and sure enough it was the bosch plug. I don't know if mb is building the engine from the factory with these plugs but they're definitely using them for service now.
Service update from WIS
The dealership plugs are now BOSCH V6S113328 (BOSCH 7434)
The original NGK are SILZKFR8D7S (NGK-95875)
The two are identical in all specifications except one, the heat range. The BOSCH have a heat range of 6 by their standards, and the NGK are a 8 by their standards
This was also confirmed by another person who I believe might not be on this forum.
You're right. The ones installed last year in service were Bosch. I returned the new ones which I had purchased from MB dealership and asked my mechanic to get NGK, as they are colder. Thanks for the info.
Thanks everyone who helped me to find the correct plug/gap.
I want to share with you my experience. This might be helpful for someone else having/will have the same issue.
Finally, I had the chance to replace the plugs. I used the NGK plugs with 0.026 gap, slightly smaller, as my mechanic advised due to having the tune.
When I was heading home, I tried to push the accelerator hard in different conditions to see if there is knocking/pinging/detonation anynymore or not.
Unfortunately, it happend once when I floored the pedal.
So, when I got home I uploaded the first tune, the one which I didn't have problem at the beginning of the tune.
So far it hasn't happend, however, I didn't have the chance to test it in different conditions to be sure the problem is solved completely.
Bottom line, I'm over it. This was the last time that I tuned a car. I'll return the ecu to its original file. Will wait for the time that I can pay more for a better car tuned properly by OEM.
It's not worth to be nervous all the time about having a blown engine. Just my opinion.
Is it 6 or 12 for v6. I feel like it's a dumb question but on a MB site (dealer) it mentioned 2 plugs per cylinder. This is my first time doing a plug change on my c43 and want to make sure I have everything I need.
Is it 6 or 12 for v6. I feel like it's a dumb question but on a MB site (dealer) it mentioned 2 plugs per cylinder. This is my first time doing a plug change on my c43 and want to make sure I have everything I need.
06-10-2021, 03:07 AM
It does sound as simple as a faulty spark plug (s). NGK is the way to go and go with the stock gap as suggested above, unless advised by your tuner. Good luck!
