Engine breaking

[BMGYaris]

hey i was doing some test today and found that on a straight flat road if go about 45-50 mph steadily, then let go of the gas i will drop to 30mph in about 8 seconds. I have an automatic. Is that normal? i also found that on moderate hills i actually slow down going down them. Normal? if not what could be wrong?
Tire pressure is A-OK and no, the engine break was not engaged:smile:
(sorry to all of those tired of my stupid topics...)

[ChinoCharles]

What gear were you in? That is what matters... in third gear the car will come down pretty quick from 45-50. In fifth it won't. I'm guessing you were probably in fourth gear. Actually, on an automatic, you can improve gas mileage by going a little over 50 until the car settles into fifth, and then when you slow down 5 mph or so the car should stay in fifth. At those speeds on a flat/downhill surface, you'll get the best mileage in 5th gear.

[ECHOKnight2000]

What gear were you in? That is what matters... in third gear the car will come down pretty quick from 45-50. In fifth it won't. I'm guessing you were probably in fourth gear. Actually, on an automatic, you can improve gas mileage by going a little over 50 until the car settles into fifth, and then when you slow down 5 mph or so the car should stay in fifth. At those speeds on a flat/downhill surface, you'll get the best mileage in 5th gear.


He has an automactic so that means there's only 4 gears (for the Yaris) the 4th being the overdrive gear.
Well there's two reasons I can think of, since the Yaris has a gated shifter (for auto) you might have accidently have the shifter in 2 or 3rd. I remember when I test drove the sedan I thought I was in drive but I was 3rd! Luckily I wasn't going that fast. Otherwise if your car was cold (meaning the engine/tranny) the car won't upshift into the overdrive gears (4th) until its warmed up. Don't worry this is normal. From my understanding its emissions reasons, cause when the engine is cold it produces more emissions! So to warm it up faster the car was design to not go into 4th until its warmed up. Make sense?
Engine breaking is ideal when you need more power (going up hill or pulling something but don't recomend that with the Yaris as it wasn't designed for that) or going down hill so you don't ride the breaks. But idealy for the best economy and less wear and tear on the drivetrain stay in drive. Hope that helps and there's nothing wrong with your car! Keep us posted!:thumbsup:

[07WYarisRS]

It's all completely normal

When going down a moderate hill and the car slows down on it's own it just means the cars speed is faster then the set throttle position. Basically you are still going the same speed but with no throttle.
The joys of drive by wire....
Also how much engine/trans breaking is applied had to do with how much or little load is on the car, engine rpm and the speeds the car is traveling.

[ChinoCharles]

4 speed auto, eh? Who knew? Oh, right... everyone but me. :iono:

[whoguy]

Actually, in the brochure I got, the Yaris automatic is actually designed to slow you down when you let off the gas, especially when going downhill....an added feature.

[eTiMaGo]

Hmm that's good in a way, one thing I really don't like about most automatics is the lack of an engine brake!

[Katana]

Oh my God, by reading the thread's title I thought that someone actually broke his engine!!!

[IsLNdbOi]

Actually, in the brochure I got, the Yaris automatic is actually designed to slow you down when you let off the gas, especially when going downhill....an added feature.

That's good to know! I thought something was wrong with mine everytime I felt it slowing down (sometimes feels like I pressed on the brake even when I hadn't) when going downhill and even when I'm coasting.

[Violin]

Engine Braking

It takes a little getting used to but it is completely normal. Next time you are going downhill at highway speeds, try tapping on the brake a little. The computer will apply even more engine braking. It is really a smart little car.

[BMGYaris]

WHOOOOOPS about the breaking :tongue: id like to say it was late but it was only 11:20pm...so...i'll go with the excuse that i only slept 2 1/2 hours the night before....

Anyway, thanks for all your responses, i guess that is ok then. but just so anyone who reads this knows, i was going 45 (thereabout) on a straight road for about 15-20 intentionally keeping it steady and stable at those speeds for the experiment. And i have done my homework pretty well at this point, def was in D, i let go of the gas and it dropped as stated above. Nothing in the car but me, though i do way 200 lbs and the car was warmed up.

who else would like to see these two combined? :slice: :moon:

[Katana]

Let me tell you something that happens on manual gear box, on 2nd gear.

When I am going at about 25km/h and I have 2nd gear, if I stop pressing the gas pedal, the car goes like crazy(going front and back!) as a result of the engine breaking.So don't worry about it!