Honda city fuel average issue

[devilcena2]

AOA, i have issue regarding fuel average of honda city
I bought honda city 2013 1.3 manual transmission (73k driven). Car had not done any tuning etc and even previous owner couldn't remember when was last time he did tuning.
Without tuning I went to lahore from Islamabad. Filled full tank and travelled around 400 km at mostly 110kph speed and just 1/4th tank was remaining when reached lahore. Considering from E to F(35 liters approx) i think it consumed like 27 liters(14.5 avg). Was expecting average to be around 16-17
After coming back i did its tuning(throttle body, oxygen sensor,map sensor, plugs cleaning), all plugs were black. And mechanic said fuel ratio ziyada hai,but no error was showing.
After that i did another trip to lahore at mostly 110kph speed but this time instead of improving fuel economy due to tuning, it gave even worse fuel average than last time around ( 10kmpl).
In city it is giving 12-13 max in Islamabad city(in odo it shows 16+). With very light foot, gears change at 1500 rpm mostly,engine breaking etc.
Can anybody guide me what is wrong. Was tuning done wrong or any problem with sensor considering plugs were black. I was expecting 16-17 average in Islamabad city and motorway also.

[pwuser15609321293]

I have 1.3 prosmatec and getting 13.3 on meter in Islamabad city. Just bought this car last month. Not sure if tunning is required for better fuel average because sometimes car started to give less average after tunning

[devilcena2]

Yes, unnecessary tuning ruins fuel average sometimes. But in my case it was long overdue. For me the worring part was plugs were black because according to mechanic fuel ratio was high. But instead of improving fuel economy after tuning it decreased especially on motorway from 14.5 last time to 10 kmpl

[Retaliator]

Honda city doesn't do well on highway

[devilcena2]

@Retaliator But a lot of people on these threads claims 16-18kmpl.
But main problem is after tuning it is giving 10kmpl now.
What do you think is the issue?
Before tuning it was 14-15 on long. During tuning plugs were black when they were opened, and according to mechanic fuel ratio was high.

[pwuser15609321293]

In my case I am not sure when was the last tunning done as I purchased it last month and not sure about previous owner when did he do that

[pwuser15609321293]

In my opinion fuel ratio in these cars are not adjusted manually as these cars have electronic throttle bodies and these are only adjusted through scanner. Are you facing high rpm on idle after tunning?

[devilcena2]

No idle is stable. I think map and maf sensors adjust air fuel ratio maybe one of them is faulty but there is no error code.
Do you think fuel ratio can be adjusted through scanner or just values are shown on scanner?

[roboxx]

Honda City doesn't require any tuning. Just Fluids changes at regular intervals and check/change spark plugs at the specified interval.

[Retaliator]

Not at speeds of 110 and above. 14.5 was a good mileage. I would suggest that u do an engine tuning from Honda dealership including tappets and throttle again (there could be a throttle calibration/ sensor issue)

[devilcena2]

Which dealership is best in Islamabad, which is not a ripoff and what would they charge for tunning and tappets approximately?

[pwuser15609321293]

Throttle calibration is done through scanner. Yes there might be issue with map or maf sensor. You can visit Honda classic I9 and tell them your issue and only agreed to let them Touch your car if they agree that the average will be better

[devilcena2]

Ok. Thanks for your help

[pwuser15609321293]

are you noticing black carbon on your silencer tail?

[devilcena2]

No