Rumbeling exhaust noise

[Jokkmokk]

Hi,

 

My Yeti will sometimes make a rumbeling noise when I start it up after it has not been used for let’s say a day. 

 

To me, the noise comes from the exhaust but the engine revs up a bit during this time. After about 15-20 seconds the noise will end and the engine will rev down to normal state. 

 

If I start driving during the noise the car will jump a bit, just like the engine doesn’t get enough fuel injected or something, I’m no mechanic so this is of course just a guess. 

 

The funny thing is that this only happens if it’s warm outside, like above 15 celsius. Especially if the car has been sitting in the sun. 

 

I have reed (from

what I remember) in other forums that this is normal behavior, a way for the engine to handle humidity or something and wasn’t any issue really. You just wait for the engine to get ready and then drive away. 

 

Now I wanted to check with you guys if there is anyone experiencing the same thing? The car mechanics couldn’t say what it’s about and I had to leave the car for a checkup for about 120$ to just search it.

[Austin 7]

Hi Jokkmokk

 

This behaviour is normal for the 1.4 TSi. 

 

Under certain conditions of engine temperature, outside temperature and humidity, the engine management software uses a special mode to rapidly heat the exhaust catalyst.  The idle speed is raised and the valve timing is altered, which gives the unusual exhaust note.  In theory you can still drive off and use the car normally, but I find it is best to keep the engine below 2000 RPM to begin with or it becomes jerky.  The alternative is to wait for a minute and play with the radio and seat settings, once the revs drop to normal you can move off.

 

I mostly notice this behaviour when the car has been used in the morning and then left for a few hours. If I start up to go out in the afternoon when it is "half warm", I get fast idle mode.

[Jokkmokk]

8 minutes ago, Austin 7 said:

Hi Jokkmokk

 

This behaviour is normal for the 1.4 TSi. 

 

Under certain conditions of engine temperature, outside temperature and humidity, the engine management software uses a special mode to rapidly heat the exhaust catalyst.  The idle speed is raised and the valve timing is altered, which gives the unusual exhaust note.  In theory you can still drive off and use the car normally, but I find it is best to keep the engine below 2000 RPM to begin with or it becomes jerky.  The alternative is to wait for a minute and play with the radio and seat settings, once the revs drop to normal you can move off.

 

I mostly notice this behaviour when the car has been used in the morning and then left for a few hours. If I start up to go out in the afternoon when it is "half warm", I get fast idle mode.

 

Okey, I was quite sure I had reed this somewhere and that it was normal. Yeah, that’s what I do to, fiddling around with the radio and looking at my perfect face......

 

Anyway, great I don’t have to pay the mechanics 120$ for nothing.

 

Thanks!