sometime when im at a redlight and the car is in neutral. the engine would rev up by itself to about 1500rpm and then come back down slowly. is this normal?

 

that sounds a little abnormal .. (having owned other small ci cars with turbo ) I'm a little curious if the hypergrounding kit or similar really does smooth out the idle / low rpm hp output.

 

Mine does that too. I think it's perfectly normal. Perhaps to make sure that the car doesn't sit and idle at one constant speed, which is bad for an engine.

 

thx i feel much better.

 

I've only really noticed a jump like that when i move the steering wheel while stopped. Of course this is caused by the power steering pump loading up to assist the steering. Otherwise just sitting there with no accessories on i've never noticed a jump in idle...

 

More questions on idle speed that I have:

What do your guys cars idle at when you first start the engine "cold"? After it's warmed up, what does it idle at?

For me it is somewhere above 1500 rpms when cold and right around 1000 when the engine is warmed up.

 

idles around 1500 rpm when it starts and slowly comes down to slightly below 1000 rpm as it warms up.

 

Same here. About 1500rpm till it's warm, then about 900 rpm.

 

I had my car for a month and a half now. I've notice the car will rev on its own about 15 sec later after I've started the car. I don't notice it much on redlights cause I'm always rev my engine anyways. I think fireball is right. it is not good to sit and idle at one speed, or in your case no speed.

 

I now have 400 miles on mine and notice that it only does the idle jump when I have the A/C on. When I have the A/C off it actually idles perfectly.

 

everytime your car jumps like that, thats when the fan is kicking on to cool the super duper radiator that this car came with, dont worry about it. Same with the AC.

 

I suspect anything that puts load on the engine will cause the car to compensate the idle.. The fan kicking on will cause load on the alternator, which will load the engine slightly which will cause the idle to raise.. Same goes for the Power Steering pump (turning the wheel may cause idle to raise) and with certainty the A/C compressor kicking in will raise the idle. This is all by design.. With a Stick shift car, its not as important, but with an automatic, the torque converter drags on the engine slightly, and a slight drop in RPM could be enough to stall it.. Not really the case with a stick car. My car does the same.. But every other car I've owned that had something more sophisticated than a carburetor does the same thing.

 

Well, i don't drive my car cold. and cold start is around 1.5K...


But the car has never reved at a stop light, or sitting.. Sounds like a bad ground or something. I have 1400miles on my car too. So i would have seen this already. Did you maybe have the A/C on? (haven't used mine really)


-Zach

 

Yeah, what he said. Mine does the same thing. Don't sweat it.

Thomas Dorris

 

1 possible answer is that idling causes carbon buildup, the engine may be revving higher to prevent it. Go ask a v8 guy about it...they will prolly say the same thing