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 06-18-2010, 09:24 PM   #1
kaotik78
Scooby Newbie
 
Member#: 153984
Join Date: Jul 2007
Location: Manchester, NH
Vehicle:
2007 Impreza
Silver

Default 07 2.5i wagon very poor acceleration

Hi,

I've got around 42k on my wagon now and I've been dealing with frankly, "piss poor acceleration" from my subaru from a dead stop still. I know I've posted about this before, but I've had two close calls now where this rig has almost gotten me t-boned pulling out into traffic, then dropping the bag, and leaving me to creep from 1500k to 3,300 and above in first gear. It doesn't launch, it just bogs down real low, pedal is to the floor.

I've unplugged the battery, left it overnight, went driving next day after everything checks out and it's in closed mode, still the same result.

I'm trying like hell here to figure it out, my wife is saying I should get rid of it, but it's a 07, no issues other than this really, I hate to get rid of it but it's been nothing but a pain to drive cause of this, you literally have to time your next move in traffic cause of it.

Has anyone else had a similar issue like this?
* Registered users of the site do not see these ads.
kaotik78 is offline   Reply With Quote
Old 06-19-2010, 12:39 AM   #2
smokeyandthebandit05
Scooby Newbie
 
Member#: 219940
Join Date: Aug 2009
Chapter/Region: Tri-State
Location: The Real North NJ
Vehicle:
2012 Forester
Silver

Default

To be honest Im not really sure but maybe a tune up with plugs, air filter,and maybe even the fuel filter?
smokeyandthebandit05 is online now   Reply With Quote
Old 06-19-2010, 12:44 AM   #3
winterwarrior
Scooby Newbie
 
Member#: 223483
Join Date: Sep 2009
Location: Maine
Vehicle:
2007 Subaru Impreza
Blue

Default

I have had the same issue with mine. I think its just the way it is with these cars...not a single ounce of power until you're over 2500 RPM...even in first. With the right foot work, you can start off strong (for a 2.5 anyway) without abusing the clutch.
winterwarrior is offline   Reply With Quote
Old 06-19-2010, 01:22 AM   #4
funky monk
Scooby Specialist
 
Member#: 143094
Join Date: Mar 2007
Chapter/Region: SCIC
Vehicle:
08 LGT
DBM

Default

Ever cleaned the MAF sensor? That may have an adverse affect on your throttle response issues.

Last edited by funky monk; 06-19-2010 at 02:40 PM. Reason: doh. sensor, not filter.
funky monk is offline   Reply With Quote
Old 06-19-2010, 04:02 AM   #5
Back Road Runner
Scooby Guru
 
Member#: 60082
Join Date: Apr 2004
Chapter/Region: MWSOC
Location: Minnesota
Vehicle:
2004 Forester STI
Silver

Default

There's a definite problem. I'd take it to the dealer and see what they say.
Back Road Runner is offline   Reply With Quote
Old 06-19-2010, 06:39 AM   #6
kaotik78
Scooby Newbie
 
Member#: 153984
Join Date: Jul 2007
Location: Manchester, NH
Vehicle:
2007 Impreza
Silver

Default

Thanks for the input, we'll see what happens!
kaotik78 is offline   Reply With Quote
Old 06-19-2010, 02:14 PM   #7
flightwatch
Scooby Specialist
 
Member#: 231058
Join Date: Nov 2009
Chapter/Region: South East
Location: St Petersburg, FL
Vehicle:
2013 Genesis Coupe
2.0T

Default

I have absolutely no problem with acceleration down low. Heck, I usually never get above 3,000rpms when I'm driving.

Let's troubleshoot:

Do you have any type of aftermarket intake? Did you or somebody else do a resonator delete?
flightwatch is offline   Reply With Quote
Old 06-19-2010, 07:03 PM   #8
chazly413
Scooby Specialist
 
Member#: 151079
Join Date: Jun 2007
Chapter/Region: MAIC
Location: College Park, MD
Vehicle:
2005 2.5RS RBP
motec system exhaust-RIP

Default

Yeah, there's definitely a problem. I have nothing but power at any point in first gear.
chazly413 is offline   Reply With Quote
Old 06-19-2010, 07:11 PM   #9
kero
Scooby Specialist
 
Member#: 94299
Join Date: Aug 2005
Chapter/Region: Tri-State
Vehicle:
2000 2.5 RS Sedan
SRP

Default

I have an auto 2.5i wagon 2007, other than the slush box shift delay and the drive by wire delay, the car seems just fine. If you have a slush box like me, you will know that you must plan ahead for passing, merging and other maneuvers as the shift delay can be rather long, thus putting you in bad situations, like myself a few times. I have 35K now and have learned to live with the slush box and plan accordingly so the power is there when needed

I hope you did your full 30k service which covers some important fluid changes such as diffies, tranny fluid, coolant, plugs, etc etc.

The 2.5i is never a screamer off the line and I wonder if you are referring more to shift delay or drive by wire issues?

If you have no CEL's I would find it hard to believe you have a sensor problem, but could be maintenance related, etc.
kero is offline   Reply With Quote
Old 06-19-2010, 08:00 PM   #10
kaotik78
Scooby Newbie
 
Member#: 153984
Join Date: Jul 2007
Location: Manchester, NH
Vehicle:
2007 Impreza
Silver

Default

Absolutely no aftermarket mods. Fluid changed, plugs/wires, gear oil, belts all done around around 30k per zee subaru book.

This is my first DBW car, my other rig was a hyundai accent that had a tib motor swap in it, had that for around 9 years or so, before I got this wagon.

Mabye it is the DBW that's causing issues, but it's not consistent because this morning it wasn't bad, then after a half hour or so of shopping with the mrs, we left and it started it's bogging act again, usually from pulling out in 1st gear, around 3k then it climbs good. Mabye I have never stopped driving like I was on a racetrack staying around 4-6k rpm wise from my old accent.

Not sure what the reference to "slushbox" is but I refer to the car as a "lead sled". Joking aside, the car/drivetrain doesn't agree with my wife because of all the clunking/bucking of power back and forth. I don't care, but I hear it from her and others when I take it out, no matter how nice I am with the clutch or sane with the gas, it still manages to ride like a bucking bronco when maneuvering in and out of city traffic.

Mabye this rig is a lemon, besides the drivability issues, the door locks, sometimes unlock themselves, the lock transponder doesn't work sometimes, even with new batteries, even the spare doesn't work half the time. Power door lock on passenger side doesn't unlock when car unlocks either.

All I know is I'm tryin like hell to love this car, my mother-in-law is on her second Forrester, she loves it, which is what made me give Subaru a try. I just don't know.

Thanks all for the other points to check, other than the shift delay, which there shouldn't be any, I don't know what else it could be (operator error my wife said jokingly)

Hell, I asked my grandmother who drove schoolbus for 37 years to give it a shot, she came back with a sour look on her face
kaotik78 is offline   Reply With Quote
Old 06-19-2010, 08:13 PM   #11
kewlboxer2
Scooby Newbie
 
Member#: 161322
Join Date: Oct 2007
Chapter/Region: Tri-State
Location: Galeton, PA
Vehicle:
06 2.5i
Regal Blue

Default

I have the slush box as well. Sometimes when pulling out it starts out in 2nd. Sure this isnt happening to you?
kewlboxer2 is offline   Reply With Quote
Old 06-19-2010, 08:55 PM   #12
KaptainKandy
Scooby Specialist
 
Member#: 152458
Join Date: Jun 2007
Chapter/Region: Tri-State
Location: N. NJ
Vehicle:
2014 Crosstrek
Orang-u-glad I didn't say

Default

60k on my 07 2.5i here and yes it really is that slow off the line.
KaptainKandy is offline   Reply With Quote
Old 06-19-2010, 09:44 PM   #13
flightwatch
Scooby Specialist
 
Member#: 231058
Join Date: Nov 2009
Chapter/Region: South East
Location: St Petersburg, FL
Vehicle:
2013 Genesis Coupe
2.0T

Default

Quote:
Originally Posted by kewlboxer2 View Post
I have the slush box as well. Sometimes when pulling out it starts out in 2nd. Sure this isnt happening to you?
Considering that slushbox refers to the 4eat and he has mentioned "clutch and 5mt in several of his posts, I'm pretty sure he doesn't have that problem...unless he selects 2nd gear.

All ragging aside, it sounds like you have more of an issue than this board is going to be able to help you with. You definitely need to get the car to the stealership asap. With all of the electrical issues that you mentioned, I wouldn't be surprised if your ecu is getting screwy signals. I'm definitely not the one to go messing around with a cars electrical system. I spent some time in rural Texas where some of the mesquite tree mechanics thought that they could rewire their pickups...lets just say that the outcome was less than favorable.

I'm assuming that you have a datalogger, and that you are also not getting a cel. Have you checked your AFR? Grounds? I'm sorry that I can't be more of a help
flightwatch is offline   Reply With Quote
Old 06-19-2010, 10:17 PM   #14
dcleal
Scooby Newbie
 
Member#: 178135
Join Date: Apr 2008
Chapter/Region: TXIC
Location: Texas
Vehicle:
2006 Impreza 2.5i
White

Default

there is a TSB for poor performance from a stop. For Automotic Transmission you can either

1. Warm the engine up until radiator fans turn on.

2. Engage parking brake, fully depress the brake pedal, put the transmission in Drive range (D) then fully depress the throttle for five seconds.

3. Put the transmission in Neutral (N) let the engine cool down for at least 5 seconds.

Repeat steps 2 and 3 four times.

or warm up engine until radiator fans turn on. Then put the transmission in 2nd gear and accelerate from 0mph WOT to 35mph. Repeat 5 times.
dcleal is offline   Reply With Quote
Old 06-19-2010, 10:46 PM   #15
Tessai
Scooby Newbie
 
Member#: 214184
Join Date: Jun 2009
Location: Dallas, TX
Vehicle:
1999 Legacy Outback
White

Default

How is the idle? Does it sit happily at/around 700rpm or does it bounce around? Usually I'd say that bogging low and smoothing out up top would indicate a vacuum leak, but typically this would result in a poor idle as well.

Given the number of electrical issues present, I'd also suspect the ECU or the throttle position sensor.

These suggestions are based on previous cars, I'm still new to Subarus myself so I can't think of anything specific. I'm sure if you searched around a bit you could find the proper diagnostics for these (such as what voltages to look for with a multimeter at the throttle position sensor) but if you can't track it down yourself, a shop is your best bet.
Tessai is offline   Reply With Quote
Old 06-19-2010, 10:56 PM   #16
ronemus
Scooby Newbie
 
Member#: 124146
Join Date: Aug 2006
Chapter/Region: MWSOC
Vehicle:
'02 Legacy GT 5MT
Titanium

Default

I had the same symptoms on my '02 due to a bad O2 sensor. If your mileage is bad, that also points to the sensor. A rich mixture doesn't make power and the engine stalls easily when the clutch is engaged. There was a hight and day difference when I replaced the sensor.
ronemus is offline   Reply With Quote
Old 06-19-2010, 10:58 PM   #17
flightwatch
Scooby Specialist
 
Member#: 231058
Join Date: Nov 2009
Chapter/Region: South East
Location: St Petersburg, FL
Vehicle:
2013 Genesis Coupe
2.0T

Default

Quote:
Originally Posted by dcleal View Post
there is a TSB for poor performance from a stop. For Automotic Transmission you can either

1. Warm the engine up until radiator fans turn on.

2. Engage parking brake, fully depress the brake pedal, put the transmission in Drive range (D) then fully depress the throttle for five seconds.

3. Put the transmission in Neutral (N) let the engine cool down for at least 5 seconds.

Repeat steps 2 and 3 four times.

or warm up engine until radiator fans turn on. Then put the transmission in 2nd gear and accelerate from 0mph WOT to 35mph. Repeat 5 times.



He has a manual transmission
flightwatch is offline   Reply With Quote
Old 06-19-2010, 11:10 PM   #18
Subaru_Nation555
Scooby Newbie
 
Member#: 83938
Join Date: Mar 2005
Chapter/Region: MAIC
Location: Arlington, VA
Vehicle:
'06 2.5i wagon
CGM

Default

I was going to post this but it says it only applies to MY 2006. Maybe it would work:

http://www.scoobymods.com/attachment...1&d=1132538662
Subaru_Nation555 is offline   Reply With Quote
Old 06-20-2010, 01:11 AM   #19
kewlboxer2
Scooby Newbie
 
Member#: 161322
Join Date: Oct 2007
Chapter/Region: Tri-State
Location: Galeton, PA
Vehicle:
06 2.5i
Regal Blue

Default

sorry... didnt catch the word clutch in 1 of his posts on this thread.

Quote:
Originally Posted by flightwatch View Post
Considering that slushbox refers to the 4eat and he has mentioned "clutch and 5mt in several of his posts, I'm pretty sure he doesn't have that problem...unless he selects 2nd gear.

All ragging aside, it sounds like you have more of an issue than this board is going to be able to help you with. You definitely need to get the car to the stealership asap. With all of the electrical issues that you mentioned, I wouldn't be surprised if your ecu is getting screwy signals. I'm definitely not the one to go messing around with a cars electrical system. I spent some time in rural Texas where some of the mesquite tree mechanics thought that they could rewire their pickups...lets just say that the outcome was less than favorable.

I'm assuming that you have a datalogger, and that you are also not getting a cel. Have you checked your AFR? Grounds? I'm sorry that I can't be more of a help
kewlboxer2 is offline   Reply With Quote
Old 06-20-2010, 03:19 AM   #20
suex
Scooby Newbie
 
Member#: 243393
Join Date: Apr 2010
Chapter/Region: NESIC
Location: Foresdale
Vehicle:
o6 impreza rs
silver

Have a Nice Day?

Get your dealer to look at the ECU and the maf. It could be a bad ground, we had similar issues with an old Taurus(locks doing ther own things) that was a bad ground....on another note, if they can't find anything make a grounding kit, it's cheap and does wonders for your ECU's abilities to run your engine....
Who knows... Good luck
suex is offline   Reply With Quote
Old 06-20-2010, 04:07 AM   #21
dcleal
Scooby Newbie
 
Member#: 178135
Join Date: Apr 2008
Chapter/Region: TXIC
Location: Texas
Vehicle:
2006 Impreza 2.5i
White

Default

sorry about that, I saw someone reference the "slushbox" so I made an assumption. For the manual transmission the process is as follows

1. Warm the engine up.
2. Put the transmission in 3rd and accelerate from 25 to 40 mph WOT

Repeat step 2 five times
dcleal is offline   Reply With Quote
Old 06-20-2010, 09:30 AM   #22
kaotik78
Scooby Newbie
 
Member#: 153984
Join Date: Jul 2007
Location: Manchester, NH
Vehicle:
2007 Impreza
Silver

Default

Hey All,

Don't be sorry, I really appreciate all the input and ideas on this. Virtually impossible to narrow it down given we're all not able to drive/see the rig up close and personal.

Got an appointment with the dealership tomorrow. Today I'll try the third gear 25-40 trick and see if that doesn't do anything for me.

Idling is actually fine. I had a TB sensor on my old Accent go bad and the rpm would bounce all over the place, even stall.

With regards to the poor performance from a stop, obviously I can't start off in 3rd gear, so I'll mess around with trying that in various ways in a open parkinglot and see if that improves anything.
kaotik78 is offline   Reply With Quote
Old 06-20-2010, 11:11 AM   #23
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 kaotik78 View Post
Absolutely no aftermarket mods. Fluid changed, plugs/wires, gear oil, belts all done around around 30k per zee subaru book.

This is my first DBW car, my other rig was a hyundai accent that had a tib motor swap in it, had that for around 9 years or so, before I got this wagon.

Mabye it is the DBW that's causing issues, but it's not consistent because this morning it wasn't bad, then after a half hour or so of shopping with the mrs, we left and it started it's bogging act again, usually from pulling out in 1st gear, around 3k then it climbs good. Mabye I have never stopped driving like I was on a racetrack staying around 4-6k rpm wise from my old accent.
classic front O2 sensor symptom. When the ECU stops "reading" data from the O2 sensor and instead uses preset parameters for fuel injection (closed loop to open loop transition) the AFR's will be more suitable and allow more power to be made.

Quote:
Originally Posted by Tessai View Post
How is the idle? Does it sit happily at/around 700rpm or does it bounce around? Usually I'd say that bogging low and smoothing out up top would indicate a vacuum leak, but typically this would result in a poor idle as well.

Given the number of electrical issues present, I'd also suspect the ECU or the throttle position sensor.
Not the ECU or TPS.

Quote:
Originally Posted by ronemus View Post
I had the same symptoms on my '02 due to a bad O2 sensor. If your mileage is bad, that also points to the sensor. A rich mixture doesn't make power and the engine stalls easily when the clutch is engaged. There was a hight and day difference when I replaced the sensor.
bingo. any mixture outside a certain range will burn poorly, rich or lean, however.

Getting rid of a 3 year old car without trying to fix it is silly. very american, but silly.

The dealer will fix it, but for a lot more $ than you could if you are handy with tools. the sensor at the dealer will be around $150 and probably cost an hour of labor at the dealer rate. good luck.
RaceFaceXC is offline   Reply With Quote
Old 06-20-2010, 11:44 AM   #24
kaotik78
Scooby Newbie
 
Member#: 153984
Join Date: Jul 2007
Location: Manchester, NH
Vehicle:
2007 Impreza
Silver

Default

Well I also found out that subaru has the ECU on my car tuned to not deliver any extra power when I call for it, regardless, in order to be efficient on gas? I learned this from watching a rallitek video regarding the accessport for our 2.5i.

Now am I going to spend 550.00 on that to fix something that should be corrected by subaru in the first place, no. I'd love to buy it but it's ridiculous, and like paying for something that should have just been done right in the first place, with regards to throttle response.

Very American to get rid of a three year old car? ROFL, I didn't take it personal, but I got a chuckle out of that cause I say the same thing, sure, if it's broke, toss it, and buy a new one.. In this instance I've had my previous car for years and years, two motors, two trans, did the work myself, it was cheap and fun. Then I get a brand new car, get past the 30k mark where no signs of issue come about, till now, and it's just one thing after another. It shouldn't be, but it is.

I'd love to get a CEL, at least that way I'd know what was wrong, or at the minimum get a pointer in a direction to start snooping around.

This just popped into my head now, the remote start that was installed on my car, the clutch switch has a jumper going to ground, so the car will start when the clutch is depressed. I disconnected that and tried to start it again, no go. So when this wire that was done at the remote start shop, is disconnected from ground, the car won't start when the clutch is depressed and key turned, hook it up, and it works. Almost like the reverse of how it should be, I'm wondering if someone fried something and this was a bandaid? I'm really going off on a limb here now I think.
kaotik78 is offline   Reply With Quote
Old 06-20-2010, 01:55 PM   #25
RaceFaceXC
NASIOC Supporter
 
Member#: 165749
Join Date: Dec 2007
Chapter/Region: South East
Location: stupid Florida
Vehicle:
2007 No YELLING
on the bus!

Default

The thing you posted about the AP from rallitek is misleading. yes, the ECU keeps the fuel injection system in closed loop for extended peroid of time after more power is called for, mostly for EPA reasons/economy. BUT, there should be sufficient power even @ 2,000rpm, to pull out in traffic in 1st gear. The point rallitek is trying to make about saying the ECu wont allow enough fuel to be injected is where it is misleading. peak torque can be made by running a richer than stoicimetric mixture, at the cost of fuel effiency and emissions. the difference between tq (and thus horsepower) from a stoic mixture of 14.7 and peak tq mixture of 13.2~ish at low rpms is going to be a couple ft/lbs. probably not even noticeable. certainly not something that would cause the low power you describe. Even with the AP or any type of tune that keep you in closed loop at all, problems will persist unless the O2 sensor is replaced.

If you have done engine/trans changes then you should just spend the $75 or on a replacement sensor and change it out yourself. you are going to pay $80+ just to have the dealer diagnose the problem.
RaceFaceXC 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
07 2.5i wagon wheels on 07 wrx dc2skel Tire & Wheel 6 06-04-2009 05:14 PM
Update to 07 STi cat-back on 07 2.5i Wagon nuggetWRX Normally Aspirated Powertrain 8 05-15-2008 12:45 PM
tien S-tech springs on an 07 2.5i wagon olsen726 Brakes, Steering & Suspension 9 10-30-2007 08:35 PM
WTB: parts for 05-07 2.5i/wagon Emilian_13 NWIC Private Classifieds 2 09-26-2007 05:53 PM
07 2.5i wagon tranny question - A/T kero Service & Maintenance 0 08-27-2007 07:49 PM


All times are GMT -4. The time now is 08:01 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.