Though following observations & guidelines are related to me & my car, but this article would definitely help all of you.I have 1000 CC vitz 2004 model with 4 cylinders. Since 2007 I am using it and I was facing its performance problem i.e. it gave me maximum 410 KM per tank (40 liter petrol) without AC in city and with AC it was doing 360 KM. Last month suddenly it's mileage went further below with AC i.e. 330 KM per full tank. It was really worrying point as I used to change its mobil oil, air filter, plugs, throttle body cleaning in time. But I mishandled it on some occasions i.e. it's engine got hot ( not much) twice. So i went to ZIC service centre [Location : exit gate of DHA to Nishat Colony Lahore Cantt] for first time. The mechanic there has 10 year experience in Toyota Indus motors and looks to me a reasonable. He checked all things fuel injector, overall engine etc and told me that all things are fine but engine looks to be week and recommended engine partial overhauling. I agreed. When the head was opened it's head gaskit was not in good shape. Also 8 valves out of 16 were not in good shape. So these things were changed and also head was also phased and cleaned. Along with this I also told him to remove the Cat Converter as it also sucks sometimes. Now it looks that this time car will give me good mileage. It basically has 8 petrol bars and first one went down after 85 km's. The man at petrol pump added 60 rupees extra fuel as it is their habit to round off figure by adding additional petrol. So if we minus kilometers for that i.e. 7 kms then we get 78 Km's for the first bar. To get accuracy for full tank drop off three km's further i.e. 78-3=75. So if we consider 75 per bar than whole tank will give me (75 X 8)=600 KM i.e. 15 km's per litre within city. I am amazed to get this average as my car hasn't even done 12km/ litre before this.Also note one thing that mostly all petrol pumps in lahore city are not good. If you go for full tank then instead of 40 you will get 36-37 litres because they just mean profit nothing else. So make habit to get your tank full in parts from different petrol pumps because when you ask them just fill 10 litres then they apply different system.Also I have heard that Total petrol pumps are best of all. But not sure if this is true or not, I will test Total petrol pump next time.Also beside other things I forgot to tell that I also switched from shell mobil oil to Zic 0W30. I don't know how good this have been for me so far.But please again keep one thing in mind that every car has different conditions and settings. So it doesn't mean what i have done to my car will suit to others as well. But car engine should be in perfect condition at all cost.Following points should always be considered for best mileage.
- Good quality mobil oil should be used and should be changed in time. Havoline and Zic are good brands according to me (There are other better brands as well but in Pakistani environments the above mentioned are goog). Also mobil oil rating should also be considered i.e. 0W30, 10W40 etc. The value before 'W' denotes the viscosity. So for small cars it shouldn't be more than 10 in any case.
- Use good oil filter, air filter and plugs. For vitz i would recommend denso.
- Clean throttle body at least twice in a year.
- Use only allowed tyre size. If you will increase tyre size either in width or height then it will definitely effect mileage but to some extent only. Also pay special attention to wheel balancing and alignment.
- Always use light foot while driving. Do not try to drive aggressively.
- Get petrol from good petrol pumps. Some petrol pumps adjust pressure in such a way that if you full your tank let say with 40 litres then actually you will get 36-37 litres. I have heard (not tested) that Total petrol pumps provide quality fuel. This would not be the case in other countries, I guess :-)
- As soon as your car gets hot due to any reason then overhaul its engine as soon as possible without any delays.
- Always try to use inner air for AC. If you will use outer air then AC filter will get chocked quickly. Also remove dust from AC filter after every three years.
- After 2-3 years gets your fuel filter changed. If you will not change it in time then it will cause real problems in cars having fuel injector system.
- Get your car's fuel injectors (if they exist) checked and cleaned once in every 2 years.
- Some cars having Cat converter also create problems in mileage when their cat converter gets chocked. So get it checked and remove if it's creating problem. This will give car bit of horse power along with bit of mileage improvement. Cat converter basically remove dangerous gases emissions and does nothing else. As in Pakistan there is no such law so it can safely be removed. But for other countries please consider this after reviewing your country rules.
- Also gets O2 Sensor and MAF sensor of your car checked for cleanliness if they exist. Also check if your car race is properly setup or not.
- Always try to use bit higher pressure in rear tyres then front tyres i.e. if you have 28PSI in front wheel then set 30PSI in rear.
Please do write positive/negative comments. Thanks for your valuable time.