Spark plugs O2 sensor got black carboned

[pwuser15421962367]

Hi guys.

Need your kind advise.
I

My car was running perfectly (no power issue, throtle speed fuel avg all were ok). Suddenly it started to lose power at 5th gear when i was coming back after 400km return out of city tour.
Very next day it started to even drop rpms to zero on pressing clutch. Fuel avg droped to 5kml which was normally 13 kml with A.c. I opened its spark plugs n O2 sensor which were completely black mailed with carbon. the same situation i faced when i changed my spark plugs 2000km before today. I changed from irridium to copper. After that i tunned my car to clean carbon n then all was ok as discussed. Now today i faced the same situation after 2000km. The night when i returned home when i faced a bit losening of power i poured Fuel system cleaner along with filling of petrol tank. I noticed a bit good effect for couple of mins but after i restarted my car, rpms were tend to drop like indian pay load. matlan hadd hogye. Avg dropped to 3 kml. Then i tunned my car again with same black carbon on spark plugs O2 sensor. But after that no significant positive change. I throtled my car to chek the silencer side n found black smoke came out with heavy foot on throtle but on normal throtle it is not black.
Some guys will ask me to scan my car with Computer. But before that i want your kind diagnosis on this situation.
Is there any culprit sensor like O2 or MAF or Coil problem or anything else?
Let me tell you engine is good and oil level and condition is Good.
Waiting for rock solid advises.

[xhaikh1]

first of all you didnt tell the car brand and secondly it may be of rich petrol intake by faulty MAF Sensor and clean the throttle and change the air filter too to feel the change

[pwuser15421962367]

One and only GLI 2010.
Throtle is clean n air filter is just new. What is rich petrol? Didnt understand the term meanings...

[haseeb.basharat]

When was the last time you changed its fuel filter and filteration gauze?

[ulislam1997]

Seems like Your maf is gone
Your car is running rich
The black smoke is unburnt petrol
Clean the maf (search how to do it on YouTube)
Beyond that
Is the check engine light on?

[ulislam1997]

Since you asked what rich is
It means engine me petrol zyada aaraha hai
Lean means kam aaraha hai
Lean is dangerous and can and will damage engine
Rich in the short run will only damage your pocket in fuel costs

[pwuser15421962367]

Ok thats fine dear.

Yes its just drinking fuel.
No check engine light On. All are off.

It means mechanic was some what right. I will take my car in evening to mechanic. He will change Maf and if things will go right then fine otherwise will do computer scanning. Most probably O2 sensor ,Maf or Coil ... one of them is culprit. What you say?

Secondly what would be the reason to damage these sensors? I said i poured Fuel System cleaner in petrol tank to clean combustion chamber and injectors... and i had done it many times but never faced that incident although car was showing some of these signs before pouring fuel cleaner but after that car to jese baith hi gaye... rpm bejaan ho kar girta tha

[dayrider]

excessive use of fuel system cleaner will damage the internals of your car

[pwuser15421962367]

Never changed fuel filter in my possession since last 40k km. Didnt know previous history.

I always use it after 5 to 6k km.

[askai37]

MAF Gone or clean it .

[haseeb.basharat]

Change fuel filter and its filteration gauze commonly known as jaali. It will cost you 2k only, it's a routine maintenance. Check MAF sensor, try replacing with a new one if its faulty.

[xhaikh1]

MAF sensor will cost you around 1000 to 1500rs if you are in karachi.
and O2 sensor are not of that cheap quality they always last long in most of the situation.
always start the expenses from lower side then move further

secondly dont use any fuel injector cleaner they aren't recommended on regular basis. use Hi-Octane fuel once in a six months or twice a year. because hioctane fuel is just like NOS of Fast and Furious which is used for performance enhancer for a while.

In high octane case you will get the result after fuel up. your mileage,engine sound,pick,performance,knocking sound all will be vanished or will be reduced by 50% to 70%.

in my case it always works.

[ulislam1997]

Maf
And ecu checking for codes should be your first priority
Then possibly o2 but I doubt a faulty o2 would cause that much havoc
Doubt it’s coils
Also
Since you’ve never changed your filter and regularly used fuel system cleaner I’m sure there’s a change the fuel filter at the front of the car (like in Honda’s I’m not sure if Toyota’s have them) is blocked or clogged

[pwuser15421962367]

I have done with scanning. Nothing found. Not on chek light engine.

Maf cleaned and throtle plugd o2 tuned now. Car is now ok after that. But didnt found any problem. But seems to be Maf or coil.

Coils are currently short in market. Kaabli 5k ki mil rahe hai Multan main. Lets c if car gets again this problem then have to purchase coils.

Fuel filter is ok otherwise will cause differently.

[pwuser15421962367]

Currently driven 100 km and avg n throtle back to its base after cleaning the throtle o2 maf n plugs. However seems to be coils are culprit. Complete scanning done. Not a single error found. Chek engine light is also off. Dont know whats wrong with market. Last year same kaabli coils were around 1800 and now Gli engines are short in market and all kaabli parts prices have been raised. If this problem again happen in near future then i will change coils.
@haseeb.basharat fuel filter is ok i think. I have found no problems regarding car avg n pick n idling besides this current issue which i thought might be culprit Coils. How do you feel that fuel filter has to be replaced?

[dayrider]

why dont you buy new coils? don't you intend to keep the car for long?

[pwuser15421962367]

Franklly speaking.
After tune up car gets back to its original pick n fuel avg.
I still doubt the dianoses. How is it possible that a culprit coil is still runing good after tune up. No diagnosis on scanner. I m waiting id this problem again happen in future then its time to proper diagnose. Why i should change coils when they are working perfectly rigt now

[ahmedstudio]

So how frequent should it be used?

[ahmedstudio]

Should it be mixed or filled whole tank?

[ahmedstudio]

Most certainly its coils and MAF sensor. Both can be inspected visually by yourself. If there are creases/lines on surface of coils, they are bad and need to be replaced. Of they seem alrigh and smooth, just spray then with contact ckeaner, wilse off with soft tissue and install back after 5 minutes.

Take out the MAF sensor and inspect it, of there is oily greasy, dirty stuff in sensot, it can be cleaned with contact cleaner. However it is a very sensitive device and should be handled carefully. Spray it with contact cleaner from more than 6 inches distance, then wipe off the dust with gentle hand with a soft tissue. Repeat this procedure twice. Install the MAF sensor after 5 minutes just to make sure the spray evaporated completely. Also spray inside the MAF connecting switch.