fuel injection, neutral and your clutch!

[michaljerzy86]

so i read somewhere that cars with direct fuel injection don't use any gas when in gear and no pressure on the throttle and being in neutral uses gas, and a good amount of it too.
so while i was driving i had the current mileage display up and when i was coasting in gear, no gas was being used then when i popped it into neutral at about 10km/h the reading popped up from --- to about 18L/100

so is this true? being in gear doesn't use gas while being in neutral does?

and if this is the case, doesn't the clutch wear out a lot faster if you have your foot on it all the time, from holding a gear while stopped??

[condor888000]

The clutch only experiences wear when it's being slipped.

The reason gas is used when in neutral is because the engine requires gas to idle. When you're stopped it doesn't matter if you're in or out of gear, your engine will use gas.

The reason that you don't use gas when coasting in gear is because the engine is being driven by the rotation of the wheels.

[victor_t]

when the car is stopped you are either in gear with the clutch fully out or you are in neutral with the clutch in. either way the engine is idling and consuming gas.

having the car in gear and the clutch half in is a ridiculously bad idea. if you don't stall the engine you'll wear the clutch fast and the cost of replacing the clutch will be a lot higher than the gas you think you might save (which you wont save anyway, because something must turn the engine, and if it's not the wheels, then it must be the combustion)


what they mean is that, if you're on the highway in 5th gear and take the foot off the gas, the engine shuts off and the car naturally slows down with no gas being used.
if under the same circumstances you put the car in neutral, the car still slows down naturally but your engine uses gas now because it needs to idle.

[victor_t]

when the car is stopped you are either in gear with the clutch fully out or you are in neutral with the clutch in. either way the engine is idling and consuming gas.

having the car in gear and the clutch half in is a ridiculously bad idea. if you don't stall the engine you'll wear the clutch fast and the cost of replacing the clutch will be a lot higher than the gas you think you might save (which you wont save anyway, because something must turn the engine, and if it's not the wheels, then it must be the combustion)


what they mean is that, if you're on the highway in 5th gear and take the foot off the gas, the engine shuts off and the car naturally slows down with no gas being used.
if under the same circumstances you put the car in neutral, the car still slows down naturally but your engine uses gas now because it needs to idle.