What are the possible reasons for high fuel consumption?
I bought a used Sehpia 1999 - 1500cc 4cyl - 4 months ago and since then i was monitoring its fuel consumption which then proved to be very high ( 200 km / 20 liters instead of 300 km / 20 liters in high ways) , i did not check inside town. An authorised service center checked the injection system and said it is OK - but one of the cylinders is just not giving it's full power capacity. And claimed that this high rate of consumption might also be normal due to low fuel quality ( I use unlead 92 oktane type.) Now I'm confused. Can you help me please? Regards.
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Re: what are the possible reasons for high fuel...
A low cylinder will cause a reduction in fuel economy. also in the winter months many states oxygenate thier fuel, it helps with emmisions but reduces economy. higher octane fuel usually has less feul economy, drop to the mid grade
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There are a lot of factors that may contribute to high fuel consumption. Does the engine run ok during normal operation? Rough idle? Check engine light on? Have the oxygen sensors scanned for operating information to determine if the fuel system is operating effeciently by a qualified service center. These sensors monitor the effeciency of the fuel system
Do you have black smoke or what looks like soot coming out of the tail pipe. The check engine light monitors fuel pressure through the computer and pressure regulator. It will come on if the pump pressure is too high or too low. If the pressure regulator is faulty it could cause excessive fuel consumption,
WHITE smoke? Or BLUE smoke? White smoke is usually caused by burning antifreeze (possible blown head gasket). Engine oil burning causes a bluish colored smoke.
Changing the oil two months ago means absolutely nothing to me. I have customers that travel 6000 miles or more in a month. Oil consumption is measured in volume over miles, not volume over months. It is normal for most 4 cylinder engines to use a little less than 1/2 quart in 1000 miles (even more than that for 6 cylinder and 8 cylinder engines).
For sure the fuel consumption if very high specially if you are a moderate driver and do not drive at very high RPM. Now the possible areas to check must be the fuel pump calibration and the timing. If this is out of order/settings then the fuel can be wasted without utilization which can result in high consumption.
High on mileage means that the engine has done a lot of work, possible that the compression is down, need to check if this is below level, if there is oil used in excess then the engine needs an overhauling subject to the cost estimated.
Cant compromise on bad fuel as this will bring down the power of the engine.
High fuleconsumption means poor setting so fuel and ignition , check fuel settings- pump calibration and timing.
Last month, my wife complained of high gas usage as well. I suddenly remembered that I had forgotten to change the air filter the last time I did the oil change. It had been over 5 months since I'd put a new one in. So, we got a new air filter, and monitored the usage, and it was back to normal again. Maybe try this?
Do you remember by chance speed vs RPM before & after work done? for example : before was 2000 RPM @ 60 MPH. Now 2200 RPM @ 60MPH ? May be coincidence, and transmission not shifting to overdrive or high gear.