Yaris Hybrid - Engine Vibrations

[yarisHybrid]

Hello,

as an owner of a new Yaris Hybrid (MY 2014 - after redesign) in Croatia, I've done 5300 miles in 4 months - and I'm very happy with the car. The consumption is about 4,0-4,5 l/100 km (58-50 mpg), but I can't not to notice something due to engine vibrations level that occurs in some point during driving.

In most times it's very smooth on engine power, like it supposed to be, but it can happen that I feel a level of vibrations from the seat and the steering wheel when accelerating on engine power (mid-power on throttle). Maybe that's normal, maybe I'm crazy... Been to the official service and they say it's due to cold wheather and it is very normal... Not sure (today it was 3 degrees and not that cold).... Becouse it is different when i dont feel that vibrations. On the other hand, there is no any strange noise coming from the engine...

What do you think? Anyone had similar experience with Yaris or other hybrid model?

Question no. 2, I'm using B (engine braking) very often - to slow down at the lights, when going down hills, saving brake pads... Is that OK?

Question no. 3 - other night was very cold and I was driving a longer route - strange thing with the engine happend. When I lifted the throttle, it revs-up a bit and then enged EV drive, but EV Mode was not possible even if Battery was full. What was that?

Thank you and greetings from Croatia.

[CPN]

I have the same vehicle just bought in October 2014... Possible answers to your questions...

Q1. Depends what you mean by "vibrations"? If you mean that the engine revs highly when you extend the accelerator into the power band on the meter then that's normal. Remember you are actually driving a CVT transmission (as well as it being a Hybrid) which is not the traditional type belt & pulleys CVT but a system of sun & planar gear clusters so its behaviour is a little different but the result is the same when you ask for power. High constant engine revs initially which fall away slowly as the car speeds up. They will never go above around the 4,800 rpm mark anyway as they are limited by the ECU.

Q2. The advice in the full manual for the hybrid is "occasional" use when descending steep hills to aid with braking... (not "very often"). In any event, and you may not be aware, since the vehicle uses regenerative braking (reverse charging the Battery by using the kinetic forward motion of the vehicle to drive the generator) anyway, the initial pressure on the brake pedal invokes this method of braking before it actually progresses to using the disc brakes so I'm not sure that you would necessarily be "saving brake pads" by overusing the "B" transmission mode in any event...

Q3. If the ambient temperature is very cold and the ECU senses that either the ICE or Catalyzers are not up to their optimum temperature (or you are asking a lot from the climate control system), the ICE will continue to run until they are and you may not go into EV mode as quickly or when you think it should be available... (if that makes sense)

[Joseph D]

I can only offer an answer to this question and re-iterate what Colin has said above:

... Question no. 2, I'm using B (engine braking) very often - to slow down at the lights, when going down hills, saving brake pads... Is that OK? ...

The short answer is no, but you will do no harm in doing so. Having said that you will not get the best out of the hybrid system using B Mode in the way you have described.

Let me explain, B Mode recaptures less kinetic energy by using engine braking to waste energy instead. The idea of B Mode is to take longer to fill the Battery by regenerating less, the flip side is that it uses engine braking to compensate for the loss of regen braking. The overall braking effect is greater than just regeneration with foot off the accelerator. The correct use for B Mode is on long downhill gradients. The way to know if you should use B Mode is if you descend a gradient in D mode and your Battery is not full by the time you get to the bottom of a downhill gradient, then you do not need to use B Mode. It is ok to ride your brakes (a no-no in a conventional car), as long as you are using regen braking only, to control your speed.

This is why, as noted in Colin's post, the manual says "occasional" use when descending steep hills to aid with braking.

For normal driving, and especially braking for lights, etc, use your foot brake, not B Mode, as you will recapture more kinetic energy that will otherwise be lost. As long as you have not filled the "regen" section of the HSI, you will not be using any disc brakes. If you are using disc brakes, it is because system needs needs to, to give you the braking you are requesting (i. e. you are braking hard!). The aim here is to use regen as much as possible and use the disc brakes as little as possible, so long gentle braking is what you are going for, where safe to do so.

Hope this helps.

PS I have visited Croatia and enjoyed your country immensely. Highlights were Plitvice Lakes National Park in Plitvička and Dubrovnik. We spent 4 days in Zadar, relaxing and exploring the surrounding area.

[Ethanedwards]

Owned the Yaris HSD since Sept12 done 41k miles as of last week. I agree with the above replies.

Never had any weird vibes sorry.

B mode..aware of its existence never used it as i believe it disables the regen braking. My suggestion is as i found out. Ignore the shiny ev button let the expensive computer do its job.

Brake pads? Checked by main dealer 22nd Dec and mine barely wornn. Gentle pedal equals more regen power better mpg etc and lets be fair smoother ride and less stress.. mpg sounds unchanged and my oem tyres lasted 35k fronts 39800 rear i think but i swapped front to back buying two at a time.

Hope that helps.

[MEP's Yaris GS]

B mode..aware of its existence never used it as i believe it disables the regen braking

It won't disable it, but will make it less effective basically due to using the engine to brake also, thus waisting energy that the reg braking could capture.

[Grumpy Cabbie]

I'm wondering if it's the early signs of a blocked/blocking EGR valve? Assuming the Yaris HSD has one. Maybe a coked up engine?

I wonder if the OP can fill up with some 98 octane unleaded and then run some petrol fuel system cleaner through his car (not sure what are good brands in Croatia). If that has an effect, then I think it could be coking up of the engine due to sub standard fuel.

If it doesn't cure it, maybe have a quick look at the EGR valve and pipes and clean them out if needed.

[kithmo]

The vibrations described sound more like wheel balance to me. Generally, vibrations through steering wheel=fronts, seat=rears.

[Ethanedwards]

Hi GC I have run my Yaris HSD on about 99.8% supermarket el cheapo meths. EGR must be ok so far for me. Though I don't do short trips. 35 mile hops with 20 miles of that at m way speeds. Maybe the OP's bargain basement fuel is worse than in rural Efficks.

[Grumpy Cabbie]

Yeah longer runs clean the engine out what ever petrol you use, but in town use or short runs the cheapo stuff really clogs things up. Give mine a nice long run of 100+ miles and it runs sweet afterwards for a few weeks before slowly choking up again.

[Cyker]

Ugh, welcome to my world! I thought petrol engines wouldn't be anywhere near as prone to this stupid EGR sooting up problem as us dervers experience, but it seems the emissions madness is spreading to you too!

(I still don't even understand WHY petrol engines have EGRs - As far as I can tell the ONLY benefit EGRs have is to reduce NOx. Diesels are prone to NOx formation because they run very lean most of the time and have high compression ratios, but petrol engines shouldn't have this problem unless they are being run very lean. It's well known petrol engines normally generate a fraction of the NOx a diesel does, so why have they bolted this thing, which has proven to make everything apart from NOx emissions worse, on to an engine type that doesn't generate high levels of NOx?!)

[PeteB]

when the Gen 3 Prius was launched they said it was to make the warm-up from cold much more efficient (helping cold start mpg and cabin warm up) and get the catalytic converters up to temperature faster

[Grumpy Cabbie]

Toyota hybrids run at very high compression ratios- almost the same as some diesels. The EGR system is much less prone to fouling unless you use the cheap petrol in town use like I did.

I think the whole issue is that you get what you pay for. Buy cheap petrol and use a car in slow heavy town traffic and you're asking for trouble

[yarisHybrid]

I can only offer an answer to this question and re-iterate what Colin has said above:

... Question no. 2, I'm using B (engine braking) very often - to slow down at the lights, when going down hills, saving brake pads... Is that OK? ...

The short answer is no, but you will do no harm in doing so. Having said that you will not get the best out of the hybrid system using B Mode in the way you have described.

Let me explain, B Mode recaptures less kinetic energy by using engine braking to waste energy instead. The idea of B Mode is to take longer to fill the Battery by regenerating less, the flip side is that it uses engine braking to compensate for the loss of regen braking. The overall braking effect is greater than just regeneration with foot off the accelerator. The correct use for B Mode is on long downhill gradients. The way to know if you should use B Mode is if you descend a gradient in D mode and your Battery is not full by the time you get to the bottom of a downhill gradient, then you do not need to use B Mode. It is ok to ride your brakes (a no-no in a conventional car), as long as you are using regen braking only, to control your speed.

This is why, as noted in Colin's post, the manual says "occasional" use when descending steep hills to aid with braking.

For normal driving, and especially braking for lights, etc, use your foot brake, not B Mode, as you will recapture more kinetic energy that will otherwise be lost. As long as you have not filled the "regen" section of the HSI, you will not be using any disc brakes. If you are using disc brakes, it is because system needs needs to, to give you the braking you are requesting (i. e. you are braking hard!). The aim here is to use regen as much as possible and use the disc brakes as little as possible, so long gentle braking is what you are going for, where safe to do so.

Hope this helps.

PS I have visited Croatia and enjoyed your country immensely. Highlights were Plitvice Lakes National Park in Plitvička and Dubrovnik. We spent 4 days in Zadar, relaxing and exploring the surrounding area.

Tnx for your answers :) And I'm glad that you visited Croatia - it is nice during the summer, and for everyone from the forum coming to Croatia, you can contact me via phone +385 (0)91 731 80 90 or e-mail kosic.darijan@gmail.com and get together on a drink and talk about our cars :)

[yarisHybrid]

The vibrations described sound more like wheel balance to me. Generally, vibrations through steering wheel=fronts, seat=rears.

I don't think it's a wheel balance becouse that small vibrations can be feeled after some time during driving - maybe after 30 mins or something like that...

I belive that the "problem", if there is any, could be from bad fuel quality and most of the time city driving... I'm not sure... It is interesitng someone has said about cleaning EGR and pipes, but it's a brand new car :/

[yarisHybrid]

Yeah longer runs clean the engine out what ever petrol you use, but in town use or short runs the cheapo stuff really clogs things up. Give mine a nice long run of 100+ miles and it runs sweet afterwards for a few weeks before slowly choking up again.

Buit I noticed that while driving in NORMAL MODE (not ECO mode), vibrations are less smaller, especially when engine is reving up in power area of the left counter

Sorry for continuous answers :/

[Joseph D]

... I belive that the "problem", if there is any, could be from bad fuel quality and most of the time city driving... I'm not sure... It is interesitng someone has said about cleaning EGR and pipes, but it's a brand new car :/

In Croatia I used INA EuroSuper BS95 in my Prius and found that to be very good, ran smoothly and got good MPG's. It was cheap too. (£1.16-£1.17 at the time) 8-) What are you using in your Yaris?

[yarisHybrid]

... I belive that the "problem", if there is any, could be from bad fuel quality and most of the time city driving... I'm not sure... It is interesitng someone has said about cleaning EGR and pipes, but it's a brand new car :/

In Croatia I used INA EuroSuper BS95 in my Prius and found that to be very good, ran smoothly and got good MPG's. It was cheap too. 8-) What are you using in your Yaris?

Yes, INA has a very good fuel (national oil company), and I used it in first two months. Now I have used for last month fuel from some local non-INA petrol station, and maybe just that could be a problem :) But they let me buy fuel on a delay via my company :/ nothing comes cheap....

[Joseph D]

... I belive that the "problem", if there is any, could be from bad fuel quality and most of the time city driving... I'm not sure... It is interesitng someone has said about cleaning EGR and pipes, but it's a brand new car :/

In Croatia I used INA EuroSuper BS95 in my Prius and found that to be very good, ran smoothly and got good MPG's. It was cheap too. 8-) What are you using in your Yaris?

Yes, INA has a very good fuel (national oil company), and I used it in first two months. Now I have used for last month fuel from some local non-INA petrol station, and maybe just that could be a problem :) But they let me buy fuel on a delay via my company :/ nothing comes cheap....

Are you using BS95 or a different grade?

[yarisHybrid]

The best from 95, when ever is possible...

On INA yes, only BS 95

[Joseph D]

The best from 95, when ever is possible...

On INA yes, only BS 95

When 95 is not possible, what are you using, 91 or 98 or something else? Are the vibrations the same (better?, worse?) when you used INA BS95 in the first 2 months?

[yarisHybrid]

Never used 91... And dont't really know is it OK to use 98... i think it is :) but never did...

I'm sure that there were no any vibrations when used fuel from INA, but that was before this cold winter... maybe the whole thing may be caused by low temperatures, around +5 to -8 C

And to say once more, I can feel vibrations only after some time during driving (30 to 45 mins). When it's started and after it's warm-up cycle, it works very smooth...

[Joseph D]

Never used 91... And dont't really know is it OK to use 98... i think it is :) but never did...

You can use 98 if 95 is not available, it won't provide any benefit and is usually more expensive.

I'm sure that there were no any vibrations when used fuel from INA, but that was before this cold winter... maybe the whole thing may be caused by low temperatures, around +5 to -8 C

And to say once more, I can feel vibrations only after some time during driving (30 to 45 mins). When it's started and after it's warm-up cycle, it works very smooth...

I'm leaning towards it being temperature related, it sounds like it is just taking longer to warm up and so spending longer in the first two warm up stages. In stage 1 particularly, the engine is set in a reasonably inefficient state which runs a bit rough, to warm up the engine and catalytic converters quicker.

See The Five Stages of Prius Hybrid Operation to learn more about the warm up stages of a hybrid. Even though it is based on a Gen II Prius most of the information is applicable to all Toyota hybrids, just some of the finer details might be different, e. g. speed thresholds.

HTH

[kithmo]

Tyres warm up as well.

[Grumpy Cabbie]

I'm trusting Croatian 98 isn't leaded. But if it isn't, then use it for a few fill ups. A lot of countries are increasing the use of ethanol in petrol and I understand that higher concentrations can cause cold running issues. What are the chances of the fuel being diluted with extra ethanol to maximise profits?

But if the car is starting to run rough at cold, then it sounds like it is coked up. Run fuel system cleaner with the expensive 98 unleaded for a full tank and see if that improves things. If it does - and it will be pretty instant, then you know the problem. If it isn't, then running the fuel cleaner and 98 unleaded won't hurt things - far from it.

[vanilla.coffee]

May I just pick up on the EGR point?

I notice the 1.5 is a VVTi engine.

Assuming it has variable valve timing on both camshafts, my guess is it may not have an EGR assembly as it would use valve overlap on the exhaust cam to draw exhaust gas back into the cylinders and thus reduce NOx that way.