Cool - Cold Weather starting - Toyota Nation Forum : Toyota Car and Truck Forums

Doonie · 11-09-2009, 11:58 AM

This started last winter and started again this Fall when the temp. went to about 37F. When the car is started, the engine revs at 2k but within 20 seconds starts revving from 2k to 3k, back and forth every few seconds. It will stop once the engine heats up. Any idea what causes this?

rainking1978 · 11-09-2009, 12:32 PM

Normal. All my fuel injected cars and motorcycles do it.

JasonA · 11-09-2009, 01:46 PM

Revving between 2000-3000 RPM unprovoked is normal?

My car never idles above about 1800 RPM cold. And at that, it's a steady idle, not bouncing 1000 RPM at a time.

rainking1978 · 11-09-2009, 02:41 PM

I don't know how cold it gets in NC but in NY it gets to below 0 and my corolla will rev pretty high till it warms up. It doesn't do that in the summer though.

JasonA · 11-09-2009, 02:55 PM

The original poster said it was 37*F outside. That's not really cold. We've had those temperatures in NC already (even inside the garage). Free-revving to 3000 RPM doesn't seem normal to me. Even with cold starts down to about 20*F here, the car doesn't rev more than 2000 RPM on its own.

And again, even at 0*F or colder, yours will oscillate between 2000 and 3000 RPM, just by itself?

It seems like something's malfunctioning in the original poster's vehicle. Maybe the throttle body needs to be cleaned, or the MAF sensor, etc. Doonie, is your check engine light on or anything?

alpha_1976 · 11-09-2009, 03:16 PM

Quote:

Originally Posted by Doonie

This started last winter and started again this Fall when the temp. went to about 37F. When the car is started, the engine revs at 2k but within 20 seconds starts revving from 2k to 3k, back and forth every few seconds. It will stop once the engine heats up. Any idea what causes this?

I am sure bouncing between 2K and 3K is not normal. Mine goes to 2.1K and then steadily goes down to 700 which is normal idle. However, temperature doesn't have much to do with what RPM it is going to be for first 10 seconds! It's always 2K-2.1K. In summer, RPMs come down quickly (after first 10 seconds or so) and in winter it takes time (may be a minute or so). I went to Toyota for this and according to them it was normal.

rainking1978 · 11-10-2009, 09:58 AM

I checked this morning when I started my corolla, even though it revved much higher then normal it didn't reach 3k rpm. Only around 2k - 2.2k

alpha_1976 · 11-10-2009, 01:20 PM

Quote:

Originally Posted by rainking1978

I checked this morning when I started my corolla, even though it revved much higher then normal it didn't reach 3k rpm. Only around 2k - 2.2k

which I guess is OK as long as it doesn't fluctuate and comes down in a normal manner to idle RPM # with time.

mikered30 · 11-10-2009, 09:24 PM

Any codes, idle hunting can be caused by a leaky intake manifold gasket.

Exage · 11-12-2009, 10:38 PM

Did you turn on the heater/fan, rear defrost or anything electrical?

My car tends to RPM hunt when I turn something electrical on when the car is dead cold. However it doesn't do it that extreme.

Pishtosh · 11-13-2009, 02:36 PM

There's a TSB calling for warranty replacement of the ECU to correct 'cold weather idle hunting' as you describe. In fact, it's on this forum, including a pdf of the actual TSB form. Try searching using some of the words I've used here. My dealer denied any knowledge of a problem until I showed him the TSB. Sigh.

dorman68 · 11-14-2009, 11:09 AM

Quote:

Originally Posted by mikered30

Any codes, idle hunting can be caused by a leaky intake manifold gasket.

I agree 100% with mikered30. This is a typical symptom of a leaking intake manifold gasket. It's a very easy and cheap diy repair. I have also experienced this issue and a new gasket solved it. Toyota has even issued a service bulletin addressing this particular issue.

wireman134 · 11-16-2009, 09:36 PM

a cold start 35degrees or less, the corolla is indeed supposed to race to approx 2k rpm until the car is about 25-45% warmed up, after that it will goto like 900rpm i believe, this is normal and believe it is good to help circulate oil during cold starts. every corolla i know does the same thing.

noooowww if u hitting 3k at startup i know thats not right at all. hope this helps

02zx9r · 11-18-2009, 06:57 AM

yesterday when I started mine at 41* it stayed at 1600rpm then slowly started droping but I took off before it totally dropped so did not see at what rpm it idles at

JasonA · 11-18-2009, 09:13 AM

Quote:

Originally Posted by 02zx9r

yesterday when I started mine at 41* it stayed at 1600rpm then slowly started droping but I took off before it totally dropped so did not see at what rpm it idles at

That's about what mine does. If it's below 35*F or so, it may flash to 1800 RPM for a bit, but it doesn't stay there long.