Need expert advice please
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w204 c63 amg
Need expert advice please
Hello,
Having issues with my car on idle, car long term fuel trims show its -19 on cold start then after a drive settle around
-14 to -15
Short term stay around 2 +-
I have cleaned my mafs and the reading are normal as it should be 5.5 to 6 g/s
Zero leakages on the intake manifold
Air temp sensor gorking normal
02 working normally
Evap system working normally ticking ect
Im so confused as to what could be causing this issue and how do i troubleshoot this so these trims long term trim come under -10 ?
so far no one has any answer ☹️
thanks
https://youtube.com/shorts/WHcQ0R8Rjig?si=AC_7PIwdwXe4S811
Having issues with my car on idle, car long term fuel trims show its -19 on cold start then after a drive settle around
-14 to -15
Short term stay around 2 +-
I have cleaned my mafs and the reading are normal as it should be 5.5 to 6 g/s
Zero leakages on the intake manifold
Air temp sensor gorking normal
02 working normally
Evap system working normally ticking ect
Im so confused as to what could be causing this issue and how do i troubleshoot this so these trims long term trim come under -10 ?
so far no one has any answer ☹️
thanks
https://youtube.com/shorts/WHcQ0R8Rjig?si=AC_7PIwdwXe4S811
Last edited by c63amg204; Jul 24, 2024 at 11:54 AM.
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Joined: Jul 2024
Posts: 34
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From: Perth, Western Australia
2012 C63 AMG PPP
Zero leakages on the intake manifold
Is your idle variable when the engine is hot?
Last edited by Chris1953; Jul 25, 2024 at 07:59 PM.
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w204 c63 amg
not at all,
the intake manifold was opened and checked for leakage as the throttle plate usually can develop cracks but mine was fine , all was cleaned and put back new PCV valve installed as well,
idle is stable when engine is hot not surge.
Thread Starter
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w204 c63 amg
Yea but those dis nothing for the trims , they still remain around -15 %
ecu is taking out 15% fuel for some unknown reason,
either not enough air or too much fuel
total stock car and air isnt the issue as MAFs are new and old ones also worked find 5 to 6 g/sec with in spec
fuel pressure is normal as well
so i dont know what to so to fix the trims and no one so far has been able to help me.
ecu is taking out 15% fuel for some unknown reason,
either not enough air or too much fuel
total stock car and air isnt the issue as MAFs are new and old ones also worked find 5 to 6 g/sec with in spec
fuel pressure is normal as well
so i dont know what to so to fix the trims and no one so far has been able to help me.
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Joined: Jul 2024
Posts: 34
Likes: 8
From: Perth, Western Australia
2012 C63 AMG PPP
Have you read this thread? It may be relevant.
https://mbworld.org/forums/c63-amg-w...im-values.html
https://mbworld.org/forums/c63-amg-w...im-values.html
Thread Starter
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w204 c63 amg
Have you read this thread? It may be relevant.
https://mbworld.org/forums/c63-amg-w...im-values.html
https://mbworld.org/forums/c63-amg-w...im-values.html
or it could be over fuelling like leaking injectors or fuel press to high which i have put new injectors (old ones were test also good) fuel pressure is normal
o2 sensor readings are normal all 4 working as they should
plugs are old but they look normal for 18k miles
new pcc valve , purge valve working as normal also swapped it to see if any change occurred didn't do anything
only thing that made a difference is if i put 3 liter of ethnol in 25 liters 95 gas which brings the trims down. To -6 or -7 which is almost normal .
I don’t understand why ethanol made the difference???
maybe car is tuned to higher octane level and my country fuel isnt good enough??
i just do not understand whats going on thats why i need advice.
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Junior Member
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From: Perth, Western Australia
2012 C63 AMG PPP
Ethanol has effectively raised the Octane rating so yes, it could be the fuel you have. What Octane rating fuel do you have available in your country? In Australia I always use BP Ultimate 98.
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w204 c63 amg
other than that all parts have been check ether replaced or checked if working , so far i have not able to find why my car LTFT are at -15 🤦🏽
Junior Member
Joined: Jul 2024
Posts: 34
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From: Perth, Western Australia
2012 C63 AMG PPP
From what you are saying, it sounds to me that the car has been retuned to deal with fuel that contains Ethanol. That seems to be the case since you added Ethanol and the trim results were close to normal. That would make sense since with an ethanol blend the injectors would be delivering more fuel.
Do you know the history of the car prior to purchase? Did the previous owner tell you it was completely standard? Where are you located?
Do you know the history of the car prior to purchase? Did the previous owner tell you it was completely standard? Where are you located?
Last edited by Chris1953; Jul 27, 2024 at 07:18 PM.
Thread Starter
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w204 c63 amg
From what you are saying, it sounds to me that the car has been retuned to deal with fuel that contains Ethanol. That seems to be the case since you added Ethanol and the trim results were close to normal. That would make sense since with an ethanol blend the injectors would be delivering more fuel.
Do you know the history of the car prior to purchase? Did the previous owner tell you it was completely standard? Where are you located?
Do you know the history of the car prior to purchase? Did the previous owner tell you it was completely standard? Where are you located?
We buy cars from japan from auction, the car only comes with mileage and if any body work was done, ecu tuning is never mentioned anywhere in any country.
since people tune c63 which isnt surprising , its just a guess that mine might have been tuned , i wish there was a way to know if it is or not .
Thats why i did the ethnol experiment as nothing else is making sense, all parts are changed new injectors , mafs filters o2 working ad they should.
the only thing that made difference was higher octane level 🤷🏽♂️
So my only option are either let it run a little rich or get a new tune on our country fuel .
Last edited by c63amg204; Jul 28, 2024 at 02:18 AM.
Junior Member
Joined: Jul 2024
Posts: 34
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From: Perth, Western Australia
2012 C63 AMG PPP
since people tune c63 which isnt surprising , its just a guess that mine might have been tuned , i wish there was a way to know if it is or not .
This thread might be of interest:
https://mbworld.org/forums/coupe-roa...ting-tune.html
Last edited by Chris1953; Jul 28, 2024 at 02:42 AM.
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w204 c63 amg
You would have to get the car plugged into a Mercedes diagnostics machine such as the STAR system.
This thread might be of interest:
https://mbworld.org/forums/coupe-roa...ting-tune.html
This thread might be of interest:
https://mbworld.org/forums/coupe-roa...ting-tune.html
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C63 AMG Saloon
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2010 C63 AMG
Possibly because there is a current thread for the same issue. Most people who use their personal time to help a stranger don't really want to duplicate the effort.
https://mbworld.org/forums/c63-amg-w...uel-trims.html
Considering you haven't been active in that thread. Did you at least search this forum called Mbworld for a solution before posting a thread with a non descriptive title?
So, now you know. Two things you can improve on. Search first and if nothing was found at least use a descriptive thread title someone else can search in the future. Good luck
https://mbworld.org/forums/c63-amg-w...uel-trims.html
Considering you haven't been active in that thread. Did you at least search this forum called Mbworld for a solution before posting a thread with a non descriptive title?
So, now you know. Two things you can improve on. Search first and if nothing was found at least use a descriptive thread title someone else can search in the future. Good luck
Thread Starter
Newbie
Joined: Jul 2024
Posts: 14
Likes: 1
w204 c63 amg
Possibly because there is a current thread for the same issue. Most people who use their personal time to help a stranger don't really want to duplicate the effort.
https://mbworld.org/forums/c63-amg-w...uel-trims.html
Considering you haven't been active in that thread. Did you at least search this forum called Mbworld for a solution before posting a thread with a non descriptive title?
So, now you know. Two things you can improve on. Search first and if nothing was found at least use a descriptive thread title someone else can search in the future. Good luck
https://mbworld.org/forums/c63-amg-w...uel-trims.html
Considering you haven't been active in that thread. Did you at least search this forum called Mbworld for a solution before posting a thread with a non descriptive title?
So, now you know. Two things you can improve on. Search first and if nothing was found at least use a descriptive thread title someone else can search in the future. Good luck
ya my description could had been better lol
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Posts: 5,352
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From: Kitchener, ON
2010 C63 AMG
Answer = Nope.
That's all the "expert" advice I have for today other than I'd recommend running through star diagnostics. All the common culprits seemed to have been covered here and the thread you should have posted in which is likely the best you'll get from internet diagnostics.
