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-   -   Cold idle 2000 rpm normal? (https://g35driver.com/forums/g35-sedan-v36-2007-08/440577-cold-idle-2000-rpm-normal.html)

bkd 05-17-2014 10:23 PM

Cold idle 2000 rpm normal?
 
Lately, on a cold start first thing in the morning, my car idles at close to 2000 rpm for about a full minute or so before settling down to normal. I don't remember it being this high - it seemed to start doing it over the winter. After it's warmed up it idles perfectly and it idles fine when stopped and restarted while warm. I've reset the ECU and done the various accelerator/throttle learning procedures and the behavior persists. I'm not sure if it's related or not but I've also noticed lately that I get a noticeable shudder sometimes when lifting off the throttle. From what I've read this is probably the ecu cutting fuel I just don't ever remember it being this rough before. The dealer has "checked it" and says there are no codes and this is normal. Car is a 2008 6MT with 58K miles. It doesn't seem to make any difference if the A/C is on or off or what temperature it is outside. (It's been between 40 and 75F over the last couple months. I've had the car for 4 years now and I'm pretty sure it wasn't doing this before recently. The car is covered under an Infiniti Elite warranty, but they say there is nothing wrong. Does anyone have any idea what might cause this?

Urbanengineer 05-17-2014 10:25 PM

Mine sits about 1400 when warming up, drops to 650 at full temp.

Shanes_G 05-17-2014 10:28 PM

Sometimes I rub the mt Fuji on the steering wheel until she calms down. Works for me.

mathnerd88 05-18-2014 11:25 AM


Originally Posted by bkd (Post 6903575)
Lately, on a cold start first thing in the morning, my car idles at close to 2000 rpm for about a full minute or so before settling down to normal. I don't remember it being this high - it seemed to start doing it over the winter. After it's warmed up it idles perfectly and it idles fine when stopped and restarted while warm. I've reset the ECU and done the various accelerator/throttle learning procedures and the behavior persists. I'm not sure if it's related or not but I've also noticed lately that I get a noticeable shudder sometimes when lifting off the throttle. From what I've read this is probably the ecu cutting fuel I just don't ever remember it being this rough before. The dealer has "checked it" and says there are no codes and this is normal. Car is a 2008 6MT with 58K miles. It doesn't seem to make any difference if the A/C is on or off or what temperature it is outside. (It's been between 40 and 75F over the last couple months. I've had the car for 4 years now and I'm pretty sure it wasn't doing this before recently. The car is covered under an Infiniti Elite warranty, but they say there is nothing wrong. Does anyone have any idea what might cause this?

Have you tried cleaning the throttle bodies? It seems to solve idling issues for most people.

muyrec 05-18-2014 12:12 PM

Same here, 2000 rpm for a minute. Its to heat up the catalytic converters quicker.

Mr. Brooks 05-18-2014 01:39 PM

There is NOTHING wrong with your car. That's normal the car is just trying to reach normal operating temperature.

bkd 05-18-2014 01:44 PM

Hmm. So this sounds normal? I could swear it used to start at about 1200 and with a single blip of the throttle it would drop down to normal/800. Now when it's at 2000 I can blip the throttle a little it and it just drops back to 2000 until it warms up. I'll check the throttle bodies and intake tract to see if they are dirty but most of the threads I've read indicate a low or surging idle is a sign of dirty throttle bodies.

Mr. Brooks 05-18-2014 01:54 PM

When you car sits for a long period of time the engine gets cold. When you start or restart the engine it will idle at 2000 rpm for a few seconds. This is to get your fluids flowing properly and to help the car reach normal operating temperature. As the engine reaches certain temperatures it will start to return to its normal idling stat. There's nothing to concern yourself with it's normal, normal, normal. Once again it's normal.

bkd 05-18-2014 02:39 PM


Originally Posted by Mr. Brooks (Post 6903704)
Once again it's normal.

Thank you. I wanted to ask since I don't know anyone else around here with a 3.5L HR engine to compare with. I've been driving this car every day for four years and I'm quite sure the idle wasn't always this high on a cold start nor did it take as long as it currently does to drop to normal. I park in a garage at work and the higher idle is particularly noticeable because of the sound of the engine and the feel of engaging/disengaging the clutch to creep slowly while the car is idling at 2000 rpm. In previous years cold weather would predictably cause it to have a high idle for longer, but now it's spring and we are having 80 degree weather and I thought that was unusual and perhaps I had a issue with an intake air temp sensor indicating it was still cold or something. Someone else here said theirs idles at 1400 while warming up and that seems about right - and how my car used to behave. I'm about 600 rpm higher than that right now. I'm okay with "normal," but apparently normal has a variance. I appreciate the input.

Mr. Brooks 05-18-2014 02:43 PM

No problem obviously you love your car and your concerned. That's normal.

takeapieandrun 05-19-2014 04:17 AM

Happens to me all the time, even on warm-ish days. Strats up at 2k, if i wait a bit it will settle down to a little over 1.

gary c 05-19-2014 09:47 AM

I've seen SLICK hit 2K rpm for an instant if she's been sitting for a few days but then the rpms drop to 1500 and warm at 650. I personally wish she wouldn't do that, sitting that long there's not enough oil on the rings.
Gary

Shawno72 05-19-2014 10:42 AM

Yep, mine this morning shot up to 2k and then dropped quickly to around 1200. I agree with Gary, I wish it wouldn't jump so high at first but what can you do?

Urbanengineer 05-19-2014 11:03 AM

Put the ebrake on and put the car in neutral. It lowers the RPMs :)

bkd 05-20-2014 04:02 PM

What people are describing as normal doesn't seem the same as what my car does.

So for science. Here is a video.

Cold start - car had been sitting in the garage for about 9 hours. Temperature in the Garage was 83 degrees. A/C was off. Car was in neutral with parking brake on. I'm not touching the throttle at all. It takes about 80 seconds before it gets down to 800 rpm.


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