Knocking noise 18-20 seconds after start then lasts for 20 ?

[ROYALE]

Hi Guys 

I have just got my yaris mk4 and noticed a knocking noise after 18-20 seconds

i took back to toyota dealer in aberdeen and was told this is a 1.5 engine caracteristic !!!

is this true

all help appreciated 

 

thank you

[flash22]

It starts after 30 sec of the engine starting, sound like a misfire or blowing exhaust ? Goes away if you press the throttle ??

[Bernard Foy]

4 hours ago, ROYALE said:

Hi Guys 

I have just got my yaris mk4 and noticed a knocking noise after 18-20 seconds

i took back to toyota dealer in aberdeen and was told this is a 1.5 engine caracteristic !!!

is this true

all help appreciated 

 

thank you

Yes it's true, and a lot of new owners have mentioned it in post. I don't even hear it now. 😃

[Big_D]

Yes, quite normal

[TonyHSD]

Knocking noises because of engine misfire are not normal and also not good at all. 
The best op can do is to record a video and share.
Use e5 99 and premium fuel usually help prevent these unpleasant sounds.  

[mr_blibby]

18 hours ago, ROYALE said:

Hi Guys 

I have just got my yaris mk4 and noticed a knocking noise after 18-20 seconds

i took back to toyota dealer in aberdeen and was told this is a 1.5 engine caracteristic !!!

is this true

all help appreciated 

 

thank you

Had it with mine. Only done c 600m and it now seems to be noticeably quieter than at new. Also tried using e5 which may have made a difference

[flash22]

10 hours ago, TonyHSD said:

Knocking noises because of engine misfire are not normal and also not good at all. 
The best op can do is to record a video and share.
Use e5 99 and premium fuel usually help prevent these unpleasant sounds.  

It's just the way they are, it's a very distinct pattern

[TonyHSD]

The knocking noises that comes from misfire are not typical 3 cylinder engine sounds, they does indeed sound similar but those metallic clunks are damper springs fully loaded and next step overload and break, or premature wear, slip , hybrid system malfunction, we all know it. 
Because that happens to a new cars it doesn’t mean it’s normal but shows how bad are the fuels in uk. You here these on your cold starts , next fill up change the petrol station or the fuel grade. 
All that said if we are talking about same metallic knockings like on gen3 hybrids when they have egr issues. 
For reference I don’t have Yaris but my many of my neighbours  does and hear those how they sound, once I was amazed how quiet was running a Yaris mk4 icon from 2021, almost no engine noise at all but just the mg1 whining to charge the Battery, so good. 

[flash22]

Nope nothing wrong it's just a sound the hybrid makes on a cold start, all engine parameters are in spec, no codes, no miss fires - nothing to do with fuels either

even had the stethoscope out on many occasions

[TonyHSD]

1 hour ago, flash22 said:

Nope nothing wrong it's just a sound the hybrid makes on a cold start, all engine parameters are in spec, no codes, no miss fires - nothing to do with fuels either

even had the stethoscope out on many occasions

That’s the typical 3 cylinder engine sound plus added mg1 load . 
I agreed with that it’s normal but if any metallic clunks like on Prius hybrids from the clutch then it’s not ok. 
 

[ROYALE]

Hi GUYS

i have listen to 4 other 1.5 yaris hybrids and they all do they same 

What the xxxx is it no one seems to know

 

thanks

[ROYALE]

also does it when hot

[flash22]

Not sure, it is either emission related or charging related

Possibly EGR or GPF pre heat ?