Welcome to the North American Subaru Impreza Owners Club Wednesday August 20, 2014
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 Technical > Normally Aspirated Powertrain

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 07-24-2013, 07:59 PM   #1
Pickler
Scooby Newbie
 
Member#: 301247
Join Date: Nov 2011
Location: Toronto
Vehicle:
09 Impreza 2.5i MT
White

Default please help, engine knocks bad at ~2500rpm

Hi guys I have a 2009 impreza 2.5i auto with only 40k miles on it. I do all the service and maintenance regularly including Spark plugs (ngk laser platinum). Anyway according to my logs engine knocks bad between 2000-3000rpm under heavy load (full throttle). So much so that IAM drops to zero and engine pulls as much timing as possible which often leads to poor low end power (more like non existent power). BUT I don't hear any knocks or pings. Once I had bad gas in there and I heard some pinging but after that no more. Even still my car pulls timing and reports knocks. my car does have a noisy heatshield/exhaust at low RPMs in hot weather. Am I a victim of false knock? I use premium gas only and car is stock.
* Registered users of the site do not see these ads.

Last edited by Pickler; 07-25-2013 at 11:22 PM.
Pickler is offline   Reply With Quote
Old 07-25-2013, 11:18 PM   #2
Pickler
Scooby Newbie
 
Member#: 301247
Join Date: Nov 2011
Location: Toronto
Vehicle:
09 Impreza 2.5i MT
White

Default

bump...
Pickler is offline   Reply With Quote
Old 07-26-2013, 02:58 AM   #3
Counterfit
Scooby Guru
 
Member#: 124254
Join Date: Aug 2006
Chapter/Region: NESIC
Location: Rhode Island
Vehicle:
2006 06 SGM Slowbaru
"The Scoobinator"

Default

You're still under warranty, so I'm going to say take it to a dealer.
Counterfit is offline   Reply With Quote
Old 07-26-2013, 07:11 AM   #4
Pickler
Scooby Newbie
 
Member#: 301247
Join Date: Nov 2011
Location: Toronto
Vehicle:
09 Impreza 2.5i MT
White

Default

will the dealership accept data logs? how am I going to prove knocking if its not audible?
Pickler is offline   Reply With Quote
Old 07-26-2013, 08:39 AM   #5
Patrick Olsen
NASIOC Supporter
 
Member#: 120
Join Date: Jul 1999
Chapter/Region: AKIC
Location: Where the Navy sends me...
Vehicle:
1997 Legacy 2.5GT
QuickSilver Metallic

Default

Tell them you can feel the car hesitating, like it's pulling timing around 2500rpm.

Have you datalogged any other, similar cars to see how they behave?
Patrick Olsen is offline   Reply With Quote
Old 07-26-2013, 08:58 AM   #6
Pickler
Scooby Newbie
 
Member#: 301247
Join Date: Nov 2011
Location: Toronto
Vehicle:
09 Impreza 2.5i MT
White

Default

Quote:
Originally Posted by Patrick Olsen View Post
Tell them you can feel the car hesitating, like it's pulling timing around 2500rpm.

Have you datalogged any other, similar cars to see how they behave?
yes but that was an acura. it had no issues with knocks despite 15 psi of boost and it built timing slowly but gradually up to redline (no dips or spikes in timing). this car I have been feeling hesitations at 2500 rpm for years. just didnt know what was wrong with it until I got a tactrix cable, and notice knock retards at those exact engine speeds. Dealership always claims the car is fine. This morning on the drive to work while climbing a small hill at 2500rpm timing dropped to 0 degrees. This was with a rich AFR mixture too.

Last edited by Pickler; 07-26-2013 at 09:05 AM.
Pickler is offline   Reply With Quote
Old 07-26-2013, 09:34 AM   #7
Patrick Olsen
NASIOC Supporter
 
Member#: 120
Join Date: Jul 1999
Chapter/Region: AKIC
Location: Where the Navy sends me...
Vehicle:
1997 Legacy 2.5GT
QuickSilver Metallic

Default

I think you missed the bit about "similar" - an Acura with an aftermarket turbo setup is not similar to your N/A 2.5i.

So, let me be more specific - have you datalogged another N/A Subaru?
Patrick Olsen is offline   Reply With Quote
Old 07-26-2013, 09:45 AM   #8
Pickler
Scooby Newbie
 
Member#: 301247
Join Date: Nov 2011
Location: Toronto
Vehicle:
09 Impreza 2.5i MT
White

Default

oh sorry but thats why i said 'but' it was an acura lol. and it was factory turbo just over boosted (rdx). I have never seen logs of other NA subarus. seen plenty of turbo subaru logs though. I actually would love to see a log of na subarus on pump gas doing some pulls.
Pickler is offline   Reply With Quote
Old 07-26-2013, 09:49 AM   #9
skyx39
Scooby Newbie
 
Member#: 342299
Join Date: Jan 2013
Chapter/Region: SWIC
Default

They can read the ECU and see that the IAM has dropped and any learned knock correction values. They won't need your datalogs if it has been knocking that much.
skyx39 is offline   Reply With Quote
Old 07-27-2013, 11:24 AM   #10
Pickler
Scooby Newbie
 
Member#: 301247
Join Date: Nov 2011
Location: Toronto
Vehicle:
09 Impreza 2.5i MT
White

Default

well I just took it to dealer and they dont know what im talking about when I mentioned the IAM.
Pickler is offline   Reply With Quote
Old 07-27-2013, 12:43 PM   #11
skyx39
Scooby Newbie
 
Member#: 342299
Join Date: Jan 2013
Chapter/Region: SWIC
Default

Quote:
Originally Posted by Pickler View Post
well I just took it to dealer and they dont know what im talking about when I mentioned the IAM.
They might use a different acronym, but they'll be able to tell of the timing is consistently being pulled. If they seem confused find a new dealer.
skyx39 is offline   Reply With Quote
Old 07-27-2013, 01:54 PM   #12
Pickler
Scooby Newbie
 
Member#: 301247
Join Date: Nov 2011
Location: Toronto
Vehicle:
09 Impreza 2.5i MT
White

Default

Quote:
Originally Posted by skyx39 View Post
They might use a different acronym, but they'll be able to tell of the timing is consistently being pulled. If they seem confused find a new dealer.
that's what i'm doing, i'm looking for a new dealership but there are not much around here. They took my car for a drive and came back saying no knock was present. Went home, hooked up my data logger and instantly read that IAM was at 0.
Pickler is offline   Reply With Quote
Old 08-01-2013, 04:14 PM   #13
djemzine
Scooby Newbie
 
Member#: 361609
Join Date: Jul 2013
Location: Richmond Hill, ON, Canada
Vehicle:
2009 Impreza 2.5i
Darj Grey

Default

Not to worry I am in the same boat, and you can use my car by testing it out with the data logger.
djemzine is offline   Reply With Quote
Old 08-01-2013, 11:41 PM   #14
Pickler
Scooby Newbie
 
Member#: 301247
Join Date: Nov 2011
Location: Toronto
Vehicle:
09 Impreza 2.5i MT
White

Default

Quote:
Originally Posted by djemzine View Post
Not to worry I am in the same boat, and you can use my car by testing it out with the data logger.
well i told you yours doesn't ping! nice meeting you today
Pickler is offline   Reply With Quote
Old 08-02-2013, 05:18 PM   #15
NH8991
Scooby Newbie
 
Member#: 197937
Join Date: Dec 2008
Chapter/Region: E. Canada
Location: Montreal, QC
Vehicle:
2009 Impreza 2.5i
Mk7 Golf R incoming

Default

As i've mentioned in other threads, i'm a big advocate of running higher octane gas (at least in my car - 09 2.5i 4EAT), running 89 or 91 (even when it was stock) certainly smoothed out the lumpy feeling it had at low revs under high load (e.g uphill in top gear). I wasn't logging the car back then so I can't comment whether it was pulling timing or not.

Even if you are stock, I definitely recommend getting a tune.
NH8991 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 04:54 AM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2014 Axivo Inc.
Copyright ©1999 - 2014, North American Subaru Impreza Owners Club, Inc.