Welcome to the North American Subaru Impreza Owners Club Wednesday September 2, 2015
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Here you can view your subscribed threads, work with private messages and edit your profile and preferences Home Registration is free! Visit the NASIOC Store NASIOC Rules Search Find other members Frequently Asked Questions Calendar Archive NASIOC Upgrade Garage Logout
Go Back   NASIOC > NASIOC General > Newbies & FAQs

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.
* Registered users of the site do not see these ads.
Reply
 
Thread Tools Display Modes
Old 05-06-2015, 08:06 PM   #1
schmidtbag
Scooby Newbie
 
Member#: 410416
Join Date: Jan 2015
Chapter/Region: NESIC
Location: MA, USA
Vehicle:
2015 Impreza 2.0i M5
red

Default High cold-start RPM? *solved*

So I bought a 2015 M5 Impreza about 2 weeks ago. The car has been and still is operating just fine, but something I didn't really pay attention to up until about a week ago is if I start the car when the engine is cold (could be anywhere between 60-80 degrees F outside) it revs to around 2000 and just stays there for a little while. After about 15 seconds it slowly starts to lower. If I give it a little gas after the first 15 seconds, it lowers much quicker. Within 1 minute it drops down to its normal RPM, which is a little below 1000.

I was wondering: is this normal and if so, why is it doing this? I'd like to point out - it doesn't do this if the engine is warm. I've heard in many cars the cause is due to a vacuum seal leak but this car is brand new and I'm the first to have ever driven it, so if something is wrong I don't know why I'm getting this problem.
* Registered users of the site do not see these ads.

Last edited by schmidtbag; 05-08-2015 at 03:39 PM.
schmidtbag is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 05-06-2015, 08:41 PM   #2
shanemclennon
Scooby Newbie
 
Member#: 207043
Join Date: Mar 2009
Location: St. John's, Canada
Vehicle:
2008 WRX

Default

Hi schmidtbag,

Have a read of section 7-10 of your owners manual. Your "problem" isn't a problem and your engine is just trying to get to its happy operating temperature as quick as possible. The owners manual is a helpful piece of information and if you're super new to Subaru then keep reading and then read some more and then search. Congrats on the new purchase.
shanemclennon is offline   Reply With Quote
Old 05-06-2015, 08:48 PM   #3
Sleepr56
Scooby Specialist
 
Member#: 67326
Join Date: Jul 2004
Chapter/Region: Tri-State
Location: CNY
Vehicle:
2015 WRX Limited
World Rally Blue Pearl

Default

This is standard new Subaru cold start operation.
Sleepr56 is offline   Reply With Quote
Old 05-06-2015, 09:01 PM   #4
Improbus
Scooby Newbie
 
Member#: 278439
Join Date: Mar 2011
Chapter/Region: MAIC
Location: Chester County PA, USA
Vehicle:
2011 WRX 306HP/333TQ
Wingless Sedan OBP

Default

Quote:
Originally Posted by schmidtbag View Post
If I give it a little gas after the first 15 seconds, it lowers much quicker. Within 1 minute it drops down to its normal RPM, which is a little below 1000.
Don't do that broski. Let her warm up before you drive her.
Improbus is offline   Reply With Quote
Old 05-06-2015, 09:29 PM   #5
schmidtbag
Scooby Newbie
 
Member#: 410416
Join Date: Jan 2015
Chapter/Region: NESIC
Location: MA, USA
Vehicle:
2015 Impreza 2.0i M5
red

Default

@shanemclennon
Ah I must've missed that part of the manual, and I wasn't exactly sure how to look up something like this. I had a feeling this was an intended purpose but it still kind of threw me off.

@Improbus
I heard that for modern cars, waiting 10-15 seconds is all you need until you start driving. I know that on older cars you should wait at least 30 seconds. I didn't rev it much anyway, only up to maybe 3K and I only tapped the gas so its not like any harm was done.


Anyway thanks for the responses. But out of curiosity, suppose there was a leak in the vacuum and it was the middle of winter - how would you know that was the problem?
schmidtbag is offline   Reply With Quote
Old 05-06-2015, 10:35 PM   #6
Back Road Runner
Scooby Guru
 
Member#: 60082
Join Date: Apr 2004
Chapter/Region: MWSOC
Location: Minnesota
Vehicle:
2004 Forester STI
Silver

Default

Cold starting is set to 1700, well at least my 04. I assume newer is similar, but the ECN has a map of the target rpms. The ECU picks the rpm target based on coolant temp. Even if it's a 70F day, if it was very cool in the morning (as Spring mornings are), your coolant temp might still be quite cold from the overnight low.
Back Road Runner is offline   Reply With Quote
Old 05-06-2015, 11:04 PM   #7
rkramer
Scooby Guru
 
Member#: 118209
Join Date: Jun 2006
Chapter/Region: MWSOC
Location: North Dakota
Vehicle:
2015 WRX Limitec

Default

Quote:
Originally Posted by Improbus View Post
Don't do that broski. Let her warm up before you drive her.

bro, please don't post any more. Your advice is 100% wrong.
rkramer is offline   Reply With Quote
Old 05-07-2015, 05:31 AM   #8
Loyale93
Newbie Moderator
Moderator
 
Member#: 91347
Join Date: Jul 2005
Chapter/Region: NESIC
Location: Tripoli, Libya
Vehicle:
'13 XV Crosstrek,
1050 Triumph Speed Triple

Default

Quote:
Originally Posted by Sleepr56 View Post
This is standard modern car cold start operation.

Fixed that for you.

OP, is this your first car? My 1993 Loyale did this.

Quote:
Originally Posted by Improbus View Post
Don't do that broski. Let her warm up before you drive her.

Stop talking.
Loyale93 is online now   Reply With Quote
Old 05-07-2015, 05:34 PM   #9
schmidtbag
Scooby Newbie
 
Member#: 410416
Join Date: Jan 2015
Chapter/Region: NESIC
Location: MA, USA
Vehicle:
2015 Impreza 2.0i M5
red

Default

Quote:
Originally Posted by Loyale93 View Post
Fixed that for you.
OP, is this your first car? My 1993 Loyale did this.
No, but this is my first manual. I had an automatic before this and it never did this to my knowledge. But, even though that car didn't rev higher, it the engine would vibrate harder when cold.

Last edited by schmidtbag; 05-07-2015 at 10:25 PM.
schmidtbag is offline   Reply With Quote
Old 05-07-2015, 05:38 PM   #10
Loyale93
Newbie Moderator
Moderator
 
Member#: 91347
Join Date: Jul 2005
Chapter/Region: NESIC
Location: Tripoli, Libya
Vehicle:
'13 XV Crosstrek,
1050 Triumph Speed Triple

Default

Quote:
Originally Posted by schmidtbag View Post
No, but this is my first manual. I had an automatic before this and it never did this to my knowledge. But, even though that car didn't rev higher, it the engine would vibrate harder when cold.
It absolutely did that. I all but guarantee it. Unless your last car was carbureted.
Loyale93 is online now   Reply With Quote
Old 05-08-2015, 03:37 PM   #11
MikeG4936
Scooby Newbie
 
Member#: 260561
Join Date: Oct 2010
Chapter/Region: TXIC
Location: Dallas, TX
Vehicle:
2006 Impreza WRX Ltd
Grey

Default

OP - if there was ANY sort of vacuum leak, you'd get a Check Engine Light (CEL). Your car is doing the same thing that literally every modern Subaru (or any other brand) does to warm up. 100% expected behavior.

Enjoy the new car!
MikeG4936 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -4. The time now is 06:29 PM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2015, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2015 Axivo Inc.
Copyright ©1999 - 2015, North American Subaru Impreza Owners Club, Inc.