Bought a gasoline passion a few weeks ago, there's been a consistent knocking of the engine when it sits in idle. Not all the time, about 3/4. It ranges from being completely absent, to subtle, to downright loud and annoying. It's clearly the engine idling and something seems to be hitting against something else. Checked to see if everything was all tight (ie panels), but still can't tell what's causing it.
Yup, it's very common and believed to be normal. Do a forum post search for "tap" or "tapping" noises and you'll probably find a few dozen posts. The consensus is that it's a design feature of a 3 cylinder engine, possibly related to the emissions system - i.e. purge valve. It's probably on other cars also, but more noticeable because the engine's like right behind your head.
Yup, it's very common and believed to be normal. Do a forum post search for "tap" or "tapping" noises and you'll probably find a few dozen posts. The consensus is that it's a design feature of a 3 cylinder engine, possibly related to the emissions system - i.e. purge valve. It's probably on other cars also, but more noticeable because the engine's like right behind your head.
Beg to differ with you.
There is no "consensus" on the cause of the problem, only what the dealers are telling us that it is the purge valve.
As for the engine being right behind your head as the reason you can hear the noise... hell you can hear the rattle bouncing off the buildings in the city.
The car sounds like an old washing machine going down the road ... Not a brand new slick little car.
I suggest we pressure our dealers to fix this before the clock/mileage runs out and we are stuck. Our car is at 19k and the tapping seems like it's getting loader. A2Jack
what grade of fuel did you use? Sometimes using lesser grade of fuel when the manufacturer specifically asked for a higher grade can cause knocking. May not be the cause, but as a checklist its a start
i could counter that it may be brand new, but it is not a slick little car. it is an anomoly - 3 cyl engines run and sound differently from more-balanced 4, 6 and 8 cyl engines. i'm pretty convinced the rattle and unevenness of idle is a characteristic of the engine design itself and not something that needs *fixing* nor can it be fixed. it's like a 3-cyl tractor on the farm. it's a little rough around the edges, especially at low rpms. unbalanced, shaky, strange, unfamiliar.
"Knocking" is a generic term any more for any regularly occuring engine noise. There's spark knock, rod knock, main bearing knock, timing chain knock (actually slap) etc etc. Off to the dealer to at least document it.
At the beginning, the engine seemed to be running "lame", especially at idle. But either I got used to it (probably ), or it did get smoother with time (now 3.500+ miles) . (Used premium only, BTW.)
IT'S NORMAL!!! I have driven several of them, i've put 5k miles on mine, and they all have the same noise, Mostly at idle. It really doesn't matter "what" is making the noise. They all sound like a sewing machine!
There is no "consensus" on the cause of the problem, only what the dealers are telling us that it is the purge valve.
I suggest we pressure our dealers to fix this before the clock/mileage runs out and we are stuck. Our car is at 19k and the tapping seems like it's getting loader. A2Jack
I have done some internet searches related to this, and am satisfied that the dealer assessment of this noise is correct. And, the symptoms of the noise are consistent with how these frequency valves work. The purge valve noise may be annoying, and smart may elect to retrofit a quieter one someday, but I wouldn't be alarmed by it. As part of the emissions control system, it would be under warranty for 100,000 miles.
The AutoGuide.com network consists of the largest network of enthusiast-owned enthusiast-operated automotive communities.
AutoGuide.com provides the latest car reviews, auto show coverage, new car prices, and automotive news. The AutoGuide network operates more than 100 automotive forums where our users consult peers for shopping information and advice, and share opinions as a community.
1976 Rover Mini
2003 Chevrolet Corvette Z06
2007 Mercedes-Benz E320 Bluetec (SOLD)
2009 smart Passion (Gone)
2011 smart Passion
"the car", "la voiture"
), or it did get smoother with time (now 3.500+ miles) 
. (Used premium only, BTW.)
Today
Linear Mode
