1500rpm cold idle

[Dominic]

Hi Guys,
I've noticed something over the years with japanese vehicles, especially my subaru 2.5i. When I crank it and the coolant is under 100F, the idle immediately jumps to 1500rpm as the cold idle. If I drive a little, or lightly tap the throttle, it drops down to 1000 or below. The hot idle on this car is ~700rpm.

Why is the cold idle so high? Isn't an idle this high in 0F weather on thick oil bad for the engine? What's the point besides keeping the engine from stalling? Let me know!

 

[Dominic]

Did some research, supposedly its EPA mandated to get hot exhaust out quickly to warm up the cat for environmental reasons.

 

[Towel_Rail]

Perhaps the higher idle helps the engine reach operating temperature sooner as well.

 

[DmanWho]

Originally Posted By: Dominic
Did some research, supposedly its EPA mandated to get hot exhaust out quickly to warm up the cat for environmental reasons.


The 1500 RPM cold start-up phenomena has been causing a stir on the SX4 forum. Any more info on the EPA mandate? If not, no problem. Everyone in colder climate areas are experiencing this, so that's a decent indicator of it being normal.

 

[MrCritical]

Dominic is correct. They want to get the catalytic converters hot asap for emissions.

 

[ThirdeYe]

If you think 1500 is worrisome, my Integra first starts at 2000rpm when cold! It drops to 1500 after a few minutes.

 

[Titan]

All my Subaru's do the same thing. Must not hurt them too bad, the UOA's are excellent, and these engines are well-known for being long-lived. Don't worry about it...

 

[refaller]

My CRV is at almost 2000 rpms with it's little 2liter, but my Odyssey (3.5) doesn't ever seem much higher than when the weather is warmer. Seems strange that it does not do the same thing. However, I doubt it matters much to engine longevity one way or another. I know people with a lot of miles on these engines from cold climates.

ref

 

[Anduril]

Neither of our Cavaliers do it, but my '02 Corolla and '96 Accord both shot up to almost 2k when started cold. Must be a Japanese vehicle thing.

 

[rpn453]

It's normal, and not just a Japanese vehicle thing. I know my '87 Grand Am idled at over 2000 rpm on -40F starts. It probably wouldn't idle smoothly and would take forever to warm up if it wasn't idling so high.

 

[Towel_Rail]

Consider also that if you turn the key and drive off (like I do), then the car will be revving over 2000 RPM anyway, so there's not much you can do about it.

 

[rcy]

Originally Posted By: refaller
My CRV is at almost 2000 rpms with it's little 2liter, but my Odyssey (3.5) doesn't ever seem much higher than when the weather is warmer. Seems strange that it does not do the same thing. However, I doubt it matters much to engine longevity one way or another. I know people with a lot of miles on these engines from cold climates.

ref


I had a 2006 Odyssey and noticed the same thing. Even on seriously cold days with a cold start it idled around 1300, pretty much the same as in the summer.

My Subaru outback with the H6, on the other had, runs 1500-1900 summer or winter, on a cold start. Usually just drop it into drive after 30 secs and drive away - never thought to blip the throttle (reminds me of carburetor days). Will try that tomorrow (supposed to be -7celsius overnight)

 

[Gary Allan]

I think that it's more of a function of these engines barely having enough power to idle. The fuel enrichment cycle does have a purpose..and one may assume that this is necessary to prevent issues in drivability when cold.

 

[road_rascal]

Both my Fords do the same high idle at startup bit. I think it's pretty common.

 

[Eddie]

My Mazda CX7 starts at 2,100 rpm and drops to 1,000 in about 20 seconds when the ambient temp is ~ 60 F. I hate it. If I push the throttle abit while cranking it starts at ~ 1,400 rpm.

 

[BuickGN]

The coldest I've had my TL was 13 degrees and the idle only went up to 1,000rpm. Right now on a 50 degree start it's under 1,000. For what it's worth it's ULEV certified and the cats are literally bolted to the heads.

 

[gomes512]

Wow never knew some cars do that. Always thought all cars stick around 1000k when cold. Learn something new everyday.

Our Jeep started doing this a while back. Never had before, highest I've seen is slightly below 1000 even when it goes south of 0 degrees. Turns out it was a bad idle air control motor.

 

[rustlerdude]

Our jeeps will be a shade under 1k when cold, never more. My vw starts cold from 35F and up at 1500 rpm with the secondary air pump on for 30 seconds, then calms down. Under 35F and it skips this because the oil is too cold, so it goes right to a normal idle instatnly. SOMETIMES it slightly misses, but most of the time its OK.

 

[mechtech2]

A high cold idle is normal - and good. It's the best thing to get oil flowing, and helps a bit for warming up. They generally go down rather quickly, nowadays.
Cars have been doing this for many decades - even with carburetors.
1500 or so is nothing. 2500 and there would be something wrong.
Be happy!