[Desperadude]

Hi everyone,

I just had my brand new 2012 5A TSX for a week. I'm driving mostly in city and in winter weather. If the fuel consumption trend continues the way it is currently, I'll do ~500km (310miles) on my 1st tank.

Today, on the way home, I put the Instantaneous Fuel Consumption Meter on all the way, and observed something strange. I hope some of you may do the same and tell me whether your car is doing that too.

Let's say I am braking at a red light. When the car is slowed down to about 10km (6mph), the Instantaneous Fuel Consumption Meter goes all the way to MAX, and stay there until the car is about to stop completely.

I also noticed that when I go downhill and am braking to slow down the car, the Instantaneous Fuel Consumption Meter also goes all the way to MAX.

If the car was actually trying to force the engine, that would be bad because I'd lose gas and wear out my brakes at the same time.

Thank you in advance for your help!

 

[Desperadude]

I forgot to mention that my TSX is a V4, and I mentioned that it's automatic.

Whether it's a "feature" of the automatic system or a real problem, I'm regretting not taking a manual. I suppose when we push down the clutch, the engine is at idle 100%. As most of my driving is in city, that would translate into fuel/breaks economy.

 

[firstsx]

can't have a V4, that could be your first problem! ... you have a 2.4L i-VTEC in-line four-cylinder DOHC
and doesn't it read out MPG, so if you hit the gas it goes minimal, when you let go of the gas it should be max... at least thats how it is in the first gen and that's what would make sense. Look carefully, you're probably reading it wrong.

 

[RBeaubien]

Thats not a fuel consumption gauge, it is a Miles Per Gallon guage. When it is pegged, it means you are getting great gas mileage.

 

[Desperadude]

Humm, looks like we got a metric vs. non metric problem again.

Thanks Firsttsx and RBeaubien for your reply, but I was taking about the same thing than you, except I talk in the metric system.

If I translate it to the US system, I'd say my MPG reading goes to ZERO (or whatever is the minimum) when I was breaking and slowing down under 6mph. It also goes to ZERO when I break when going downhill.

 

[din9lebeRrY]

Humm, looks like we got a metric vs. non metric problem again.

Thanks Firsttsx and RBeaubien for your reply, but I was taking about the same thing than you, except I talk in the metric system.

If I translate it to the US system, I'd say my MPG reading goes to ZERO (or whatever is the minimum) when I was breaking and slowing down under 6mph. It also goes to ZERO when I break when going downhill.

That makes no sense. Metric versus imperial, if you let off the gas and are moving (I.e coasting/decelerating/braking) you are giving no throttle but moving. That equates to a high mpg. Once you get to near zero it drops to 0 instantaneous mpg. Makes sense bc a stationary car on is burning gas but not moving. That is 0 miles per gallon.

 

[Desperadude]

That makes no sense. Metric versus imperial, if you let off the gas and are moving (I.e coasting/decelerating/braking) you are giving no throttle but moving. That equates to a high mpg. Once you get to near zero it drops to 0 instantaneous mpg. Makes sense bc a stationary car on is burning gas but not moving. That is 0 miles per gallon.

You're right. I've been silly. In my head I associated the mpg measure only to the amount of gas that the computer injects into the engine. But of course we have to take into account the speed of the car in order to calculate mpg.

 

[cYn]

Yup dingle is right.

The instantaneous mpg is also based off of the throttle pedal along with speed and distance traveled