Suzuki Liana Average Issue

[sameerahmed2811]

I am getting a very bad average of 7 km/l on my Suzuki Liana 2006 Rxi. I've done complete tuning, all injectors and sensors are fine but the average is same. So I decided to switch on LPG, I am getting very bad average on LPG also which is 7.5 km/l. I am confused what to do, I've done everything I possibly can. I've changed LPG kit but the average is same. Engine is also in optimum condition. What can be the problem, please help

[shamimcrcr]

It is good to remove CNG from liana. Is your radiator fan auto or direct. Pls share your car scanner readings at idle when engine temperature becomes 95C on petrol without electric load. Then diagnosis can be possible

[sameerahmed2811]

I decided to run Liana on petrol but according to the average I'm getting, petrol will make me bankrupt that's the only reason I switched to gas. My fan is direct, I am looking forward to convert it on auto. By the way, does radiator fan effects fuel average

[shamimcrcr]

Yes radiator fan reduce fuel economy. If petrol fuel avg is good then you will not need cng. Liana can give you upto 17-18km/liter on highway on petrol on lighter foot. I may help you to improve fuel economy as i also have Liana. Just Give me scanner readings at 95C without electric load on petrol only, not CNG. If you can't provide scanner readings and want to run liana with same setup then just improve your ignition system by replacing only your plugs with good condition original NGK iridium if coils are good. This will improve your fuel economy.

[sameerahmed2811]

I've recently done scanner reading but I forgot to record these readings, the inspector says that all of my readings are fine and the is at it's best setting. I've think of changing spark plugs but my mechanic says they are fine and they don't need to be changed. Only ignition coils are remaining but what are the symptoms of a weak ignition coil and how can I check it

[shamimcrcr]

I am sure your mechanic is not diagnosing right. main symptoms of bad ignition coil is missing or jerk or it may be leaking current. However you must change your spark plugs keeping in view that its iridium with right length of tip. Too small tip is not good and spark plug should not be shorted with yellow stain. As little faulty spark plug may not show any bad symptom but affect fuel economy first before complete failure.

[sameerahmed2811]

But the point is does spark plugs decreases this amount of fuel average. I mean Liana should give 12 km/l without AC but I am getting 7.5 km/l without AC, means there is a major fallback which is consuming half of my fuel. As long as coil is concerned, my car gives a little amount of jerk when I drive with light foot at the speed of 30-40. If I pull it hard then this jerking doesn't even notice but my mechanic said that this is a problem in gear.

[shamimcrcr]

Dear thats why i want your scanner readings to find exact problem. Because there are many things which affects fuel average. May be your MAP sensor or IAT sensor or Oxygen sensor etc are faulty and giving wrong readings to ECU. May be you have very low engine compression as Liana each engine cylinder compression should be 150psi or May be you are running rich or lean. A good diagnosis is necessary to save your money but I don't know anything therefore i am using hit and trial method because in Liana mostly fuel average fault is due to bad ignition coil and spark plugs. You may buy obdII scanner for readings whenever you want.

[sameerahmed2811]

One thing I want to mention is that after recent tuning my car is in water dropping condition but still the average is same. As far as coils are concerned, bad or weak ignition coils produces misfires, but I haven't faced any misfire yet which means that my coils aren't weak. Correct me if I'm wrong.

[shamimcrcr]

Dear weak, leaking current coils do not cause misfire necessarily but failed coil or spark plug cause misfire and water dropping does not necessarily mean good average. You need too see your fuel trims also.

[kamarn2]

Can you give optimal ranges for sensors reading n fuel trims etc, my liana 2009 rxi is also giving 7/8 avg after tunning n sensors cleaning. Here electrician in karachi don’t know much about readings through obd2.. they just check no dtc errors found.
I bought scanner but dont know about reading range