Welcome to the North American Subaru Impreza Owners Club Wednesday October 22, 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 03-05-2011, 04:36 PM   #1
Geoffman72
Scooby Newbie
 
Member#: 27891
Join Date: Oct 2002
Location: Rochester, NY
Vehicle:
2001 Impreza 2.5 RS
Blue Ridge Pearl

Default 2007 OBS troubles

Hi all,

Vehicle in question is my girlfriends 2007 OBS with the 4EAT and 46,xxx on it. She bought it back in September and its having a few issues so we'll start with the one that could be the biggest problem.

1) Transmission slam shifting itself from first to second when cold and light throttle. I've only had it happen to me once but she complains of it happening most nights leaving work.

2) Throttle surging at the transition from low speed coasting to light throttle. I've seen theres a reflash available for this issue but the dealer I go through seemed hesitant to apply the fix.

3) Cranks over but wont fire on cold mornings when I've started it for half a minute to get my car out from in front of hers. Flooding and 2007 shouldn't be in the same sentence with the mileage on it.

Anyone had a similar experience? TIA
* Registered users of the site do not see these ads.
Geoffman72 is offline   Reply With Quote
Old 03-05-2011, 08:20 PM   #2
blackfang
Scooby Guru
 
Member#: 131347
Join Date: Nov 2006
Chapter/Region: MAIC
Location: Richmond Va
Vehicle:
2007 Legacy 2.5i SE
98 Z/28, VN 900 custom

Default

1) Well when the transmission is cold and the weather is cold, the fluid is cold and it can be very jerky to almost hard shifts during shifting until the fluid warms up. Have her warm the car up for 5-10 minutes and drive and see if that helps. Starting a car up when it is cold out and immediately driving it and expecting flawless operation isn't going to happen.

2) Ignore the reflash for now and address the problem by having a technician diagnose the issue. Everyone on the internet reads and interprets the term reflash and assumes this fixes everything. She may have already have the most updated logic in the ECU.

3) Are you giving it gas when this happens or are you starting the car without giving it gas? I ask this because there are people that still mash the gas medal on fuel injected cars and wonder why they are hard to start. If that is not the case, you could have a fuel issue or a fuel pressure issue.
blackfang is offline   Reply With Quote
Old 03-05-2011, 08:20 PM   #3
blackfang
Scooby Guru
 
Member#: 131347
Join Date: Nov 2006
Chapter/Region: MAIC
Location: Richmond Va
Vehicle:
2007 Legacy 2.5i SE
98 Z/28, VN 900 custom

Default

Double post.
blackfang is offline   Reply With Quote
Old 03-05-2011, 08:53 PM   #4
Geoffman72
Scooby Newbie
 
Member#: 27891
Join Date: Oct 2002
Location: Rochester, NY
Vehicle:
2001 Impreza 2.5 RS
Blue Ridge Pearl

Default

I should add that I work on all my cars and don't usually have a problem with diagnosis. Just seeking other opinions to see if there anything I've missed before I take anything apart.


When I said slam shifting I didn't mean anything that could be confused with cold fluid but more akin to a screwdriver being jammed in the flywheel teeth for a split second between shifts. It acts like the TCU is confused for a second at light throttle.

For problem number two, techs at the local dealer have diagnosed twice for all three of these problems and couldn't find anything. They knew of the reflash but since it didn't have a problem for them they were hesistant to do that.

For problem three, definitely not a thought of giving it gas until the final act of treating it like a flooded carbureted car. It did start after sitting for a min then giving it part throttle to let air clear the cylinders.


To be perfectly honest any time I drive the car 99% of the time its as perfect as a 5 year old Subaru with 46k should be. Only issues I've had are the one time it shifted hard, then once when it didn't start, and a few instances of light throttle surging.

Just want this solved so my girlfriend will stop being so doom and gloom about her car. Don't want her getting a bad taste for Subarus after my RS has been mostly bulletproof for 160k!
Geoffman72 is offline   Reply With Quote
Old 03-06-2011, 12:49 AM   #5
JustROLLIN
Scooby Newbie
 
Member#: 267646
Join Date: Dec 2010
Chapter/Region: MWSOC
Location: Mpls, MN
Vehicle:
2007 2.5i Wagon
Pearl White

Default

#1 & #2

I have both of those issues to some degree. Mine does not "slam" into 2nd gear, but it does shift rather firmly. As mentioned above, this is not all that uncommon in cold climates. I am located in MN, so needless to say, its something I have experienced before on many different vehicles.
JustROLLIN is offline   Reply With Quote
Old 03-06-2011, 12:55 AM   #6
RaceFaceXC
NASIOC Supporter
 
Member#: 165749
Join Date: Dec 2007
Chapter/Region: South East
Location: stupid Florida
Vehicle:
2007 No YELLING
on the bus!

Default

Has anyone checked the ATF fluid?
RaceFaceXC is online now   Reply With Quote
Old 03-06-2011, 07:39 AM   #7
blackfang
Scooby Guru
 
Member#: 131347
Join Date: Nov 2006
Chapter/Region: MAIC
Location: Richmond Va
Vehicle:
2007 Legacy 2.5i SE
98 Z/28, VN 900 custom

Default

Quote:
Originally Posted by Geoffman72 View Post
When I said slam shifting I didn't mean anything that could be confused with cold fluid but more akin to a screwdriver being jammed in the flywheel teeth for a split second between shifts. It acts like the TCU is confused for a second at light throttle.
Ok, but does this happen when it is cold out and the vehicle has not been warmed up or does it happen all the time? I ask this is because if the fluid is cold, the TCM will act a little more erratic and hard shifts can be expected. The TCM also reads the fluid temps too. Also sometimes when it is cold it will shift faster into higher gear to allow it to warm up to operating temps faster.

If the above is not an issue and this happens all the time when warm and cold have you checked the fluid levels?

As to why the techs did not reflash the vehicle that is odd. Since they have diagnosed the issue and found nothing and they know there is a reflash for it and the ECM does not have the current logic, then they should have reflashed it. Reflashes are covered for 8 years or 80k whichever comes first.
blackfang is offline   Reply With Quote
Old 03-06-2011, 09:40 AM   #8
RaceFaceXC
NASIOC Supporter
 
Member#: 165749
Join Date: Dec 2007
Chapter/Region: South East
Location: stupid Florida
Vehicle:
2007 No YELLING
on the bus!

Default

Quote:
Originally Posted by blackfang

Ok, but does this happen when it is cold out and the vehicle has not been warmed up or does it happen all the time? I ask this is because if the fluid is cold, the TCM will act a little more erratic and hard shifts can be expected. The TCM also reads the fluid temps too. Also sometimes when it is cold it will shift faster into higher gear to allow it to warm up to operating temps faster.

If the above is not an issue and this happens all the time when warm and cold have you checked the fluid levels?

As to why the techs did not reflash the vehicle that is odd. Since they have diagnosed the issue and found nothing and they know there is a reflash for it and the ECM does not have the current logic, then they should have reflashed it. Reflashes are covered for 8 years or 80k whichever comes first.
The OP clearly stated that it happens when its cold and fist driving. So obviously the fluid is cold. The "techs" didnt flash the ecu because they could not reproduce the problem. Flashing changes many things and can cause "problems", in high mile/wear vehicles its more likely to cause unwanted behavior. If the vehicle was fine before and now shifts abnormally, software is unlikely to correct it.

Personally id say changing the atf fluid for a quality syn fluid would be a good place to start. It will have more stability across temp range and probably needs to be done anyway. I think its recommended at 40k miles by subaru and its cheap and easy to do.
RaceFaceXC is online now   Reply With Quote
Old 03-06-2011, 12:57 PM   #9
blackfang
Scooby Guru
 
Member#: 131347
Join Date: Nov 2006
Chapter/Region: MAIC
Location: Richmond Va
Vehicle:
2007 Legacy 2.5i SE
98 Z/28, VN 900 custom

Default

Quote:
Originally Posted by RaceFaceXC View Post
The OP clearly stated that it happens when its cold and fist driving. So obviously the fluid is cold.
There is nothing in the OP that clearly states when it is first driven only. He mentioned when cold and most nights and it only happening once to him. That is why I inquired with my posts to see if it is happening all the time when driving or only when first driving because it could be user error. There is a difference in cold fluid when first driving verse the same but in cold weather. I have seen several people who complain of the same thing and in most of those cases it is because they jump in the car when it is cold outside and go and expect the car to drive normally. That is not always the case.


Quote:
The "techs" didnt flash the ecu because they could not reproduce the problem. Flashing changes many things and can cause "problems", in high mile/wear vehicles its more likely to cause unwanted behavior. If the vehicle was fine before and now shifts abnormally, software is unlikely to correct it.
There is nothing wrong with reflashing a vehicle that has an issue when they have ruled all other possibilities out. I wouldn't reflash a vehicle as the first step without looking at other components first. If there is a reflash out there for that concern, and the ECM doesn't have that current logic already, then reflash it.
Also, please explain what kind of problems reflashing a ECM with factory programming can do?
How does 46k equate to high mileage?
The reflash was not for the hard shifting, it was for throttle surging from low speed coasting and light throttle.

Quote:
Personally id say changing the atf fluid for a quality syn fluid would be a good place to start. It will have more stability across temp range and probably needs to be done anyway. I think its recommended at 40k miles by subaru and its cheap and easy to do.
Changing the fluid will not address that concern if his concern is related to driving when the trans fluid is cold and the temps are cold. Even synthetic fluid will still do the same if it is 10-20 degrees out and you just jump in the car and go. Also Subaru recommends replacing the fluid every 15,000 miles in severe service, but recommends inspecting it at 30k. We always changed the fluid at 30,000.
blackfang is offline   Reply With Quote
Old 03-06-2011, 05:54 PM   #10
archdude
Scooby Newbie
 
Member#: 205968
Join Date: Mar 2009
Location: New York
Vehicle:
2009

Default

My car used to shift a little jerky sometimes back when I had about 10k miles on it. Once i flushed the trans fluid, it seemed to stop happening. Check the ATF fluid, if it's not clean/pink looking then it's worth a change regardless.
archdude 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

Similar Threads
Thread Thread Starter Forum Replies Last Post
WTB : 2002-2007 OBS stock suspension twagoon NWIC Private Classifieds 2 01-28-2011 11:08 PM
97 OBS trouble starting.. not the battery... nperkins Electrical & Lighting 3 01-27-2010 08:52 AM
30 MPG in 2007 OBS supernootz General Community 1 08-26-2007 09:57 PM
Trouble finding Brake Pads & Rotor 2002 OBS Mayor McCheese1 Brakes, Steering & Suspension 4 09-12-2005 12:51 PM


All times are GMT -4. The time now is 09:51 PM.


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.