Rough idle

[blackbeagle]

We've had our Coupe for a week now. I noticed that when I'm at a stop light, the engine idles kind of rough. I didn't expect a Lexus type engine, but I'm wondering if this is normal. It sounds like it's sputtering a bit, like a 84 Escort. Am I just hearing things or is this normal?

I remember about 5 years ago, there was a product sold on TV called 'Motor Up'. I used this and it was great. If you had an older car that idles rough where the engines actually shakes, you pour a bottle in and within 5 seconds, the engines is smooth as glass. I'm not exaggerating. It worked on my Isuzu Rodeo like a charm as well as some of my buddies older cars. I know you're not suppose to add additives to this car but I could certainly use some of that based on what I'm hearing.

[orngandblack]

I wouldnt add anything. Take it back and let the dealer check it out.

[Old smart]

In consonance with another subject here, I proffered the fact that a 3-cylinder, 4-stroke engine sounds and idles a bit odd. There can be no one power stroke at the top of each revolution, nor can there be one every two, et al. It may take six or twelve crank revolutions for everything to come out even and start all over again. The old SAAB and DKW 3-cylinder, 2-strokers were different - 3 power strokes every revolution at 120-degree intervals.

Harley-Davidson could easily time power strokes on 2nd-alternate revolutions (like Vincent, Velocette and J.A.P. did), but they choose not to in order to maintain the traditional H-D "potato-potato" thump.

[blackbeagle]

Originally Posted by Old smart

In consonance with another subject here, I proffered the fact that a 3-cylinder, 4-stroke engine sounds and idles a bit odd. There can be no one power stroke at the top of each revolution, nor can there be one every two, et al. It may take six or twelve crank revolutions for everything to come out even and start all over again. The old SAAB and DKW 3-cylinder, 2-strokers were different - 3 power strokes every revolution at 120-degree intervals.

Harley-Davidson could easily time power strokes on alternate revolutions (like Vincent, Velocette and J.A.P. did), but they choose not to in order to maintain the traditional H-D "potato-potato" thump.

In the words of Jackie Chan, "I don't understand the words that are coming out of your mouth"

[knutliott]

Translation: because of the way the pistons work in a smart car's engine, the sound of the engine is naturally uneven.

[SmartAzz]

Originally Posted by knutliott

Translation: because of the way the pistons work in a smart car's engine, the sound of the engine is naturally uneven.

It does sound funny, kind of agricultural I'd say if it is truly rough though,where the car is shaking, I'd take it in - maybe try adding some new gas first to see if that improves it.

[MinnySmart]

I remember the idle in the demo I drove being pretty rough... it's definitely not as rough in my own smart, but it is still rougher than a normal 4 or 6 cylinder vehicle.

[xcrew229x]

Mine occasionally seems to idle a little slow at lights, etc, but not really rough. More like it's trying to make up it's little computer mind, or jostling between clutch engagement and disengagement. Hope it's just a normal ECM thing.

[RussBarnes]

Give it a break, the rings aren't seated, the compression pressure isn't up, strange parts are still getting intimate with each other so they can hold hands in harmony. Mine at 1400 miles is so much smoother, the trans is prorgrammed to my soft touch and I think I will join the 350 club this weekend. Neat cars, but not your father's Olds.

[JIM VINYARD]

If there is no odor of unburned gas then I would think everything is ok , but just to make you fell at ease you should have it cheched out incase there is some problem. Happy motoring.