Subaru Forester Owners Forum banner

1 - 17 of 17 Posts
S

·
Guest
Joined
·
0 Posts
Discussion Starter #1
I have a stock XT manual with the factory boost gauge that is now only hitting .3-.4 at the most. I swear it used to go up to around .8, and I feel that my acceleration has definitely started lagging. Anybody with this car knows that you would be hard-pressed to floor the thing in any sort of traffic, but now I can floor it and the turbo definitely comes on slower. Does anyone have any idea what could be wrong with it? I have no modifications and it's still under warranty, but I can't stand dealing with the dealer. Any help would be appreciated. Thanks.

I do have an oil consumption problem that comes and goes (1 qt per 2500 miles). I've been down that road before, i.e. the dealer says it is "acceptable," but I wonder if this has any influence on the turbo??
 
S

·
Guest
Joined
·
0 Posts
Discussion Starter #2
sounds like a problem with the turbo.....but needs to be properly diagnosed...
 

·
Registered
2006 RX8
Joined
·
423 Posts
It sounds like your factory boost controller is currently passive and the boost is being controlled by the wastegate vacuum canister alone. This static wastegate boost is typically anywhere from 5-7psi depending on the turbo and application. Anytime you see a turbo car running this kind of low boost this is a good place to start looking.

I had this exact thing happen to my Fxt. The car was acting sluggish and I immediately noticed that the boost was down to around 6-7psi maximum. I double checked all of my boost line connections and all was good. I finally dropped my battery/power and let the capacitance bleed-off for about half an hour, then reconnected the power and did a keyswitch on-to-reset. After that, I took her for a ride and the boost was back up to the 12psi max range and the car felt normal again.

Btw- I had no CEL's of any sort, and other than being sluggish and low boost, the car gave no other indicators of problems.


Sound familiar?
 
S

·
Guest
Joined
·
0 Posts
Discussion Starter #4
Thanks! That worked like a charm. Really, I can't thank you enough.
 

·
Premium Member
06 FXT
Joined
·
2,262 Posts
N10S said:
I had this exact thing happen to my Fxt. The car was acting sluggish and I immediately noticed that the boost was down to around 6-7psi maximum. I double checked all of my boost line connections and all was good. I finally dropped my battery/power and let the capacitance bleed-off for about half an hour, then reconnected the power and did a keyswitch on-to-reset. After that, I took her for a ride and the boost was back up to the 12psi max range and the car felt normal again.
What year is your FXT and how many times did this problem occurred?

In any case, thank you for the tip & solution to the problem.
 

·
Registered
2006 RX8
Joined
·
423 Posts
MY Fxt is an 05, and I only had this happen to one time since I picked-it up new at the dealership. The car had around 8,000 miles on it at the time. Glad the information helped!

Jeff
 

·
Premium Member
Joined
·
497 Posts
N10S said:
MY Fxt is an 05, and I only had this happen to one time since I picked-it up new at the dealership. The car had around 8,000 miles on it at the time. Glad the information helped!

Jeff
ditto for me also...happened one time after I was stuck in traffic and had the AC blasting. Boost maxed out at 0.03MPa. Scheduled a diagnosis for a week later, but it had already fixed itself...
 

·
Registered
04 FXT
Joined
·
291 Posts
Hi everyone, I'm not trying to jack this tread, but simply to refresh problem that seems to be somewhat PITA to too many many Subie owners.
I have an 04' FXT and sounds like it may be having the same problem as you guys experienced. When I'd disconnected the battery, and stepped on brake ~15sec, and reconnected the sluggishness remained.
At 2-3K RPM It feels as if I'm pulling small trailer.
Q 4 "N10S"; what did you mean by: ...then reconnected the power and did a key switch on-to-reset(?)
Maybe I'm doing something wrong?
I've heard of similar things that could be part of this problem;
1.) Bad Coil Packs
2.) Dirty Fuel Sock
3.) Bad Fuel Pump or Filter
4.) Bad O2 Sensor
5.) Lack of a grounding kit


I'm somewhat disappointed/tired of something that would've never happen on my Si no matter how much I bead on it.
It has 27K, I've put so much TLC into this damn wagon; Mobil1 synthetic oil, Redline trans/diff changed and maintained since new,COBB's down-pipe, STi cbe, Perrin filter, diff/shifter KB-bushings, tires @ 40PSI, always 93 Octane gas.
What the F?
Guys I need some educated opinions on what could be the cause for this sluggishness/hesitation throughout the whole midrange rpm band.
Thanx in advance for any write ups/suggestions.

Cody
04' FXT (5mt)
 

·
Registered
2006 RX8
Joined
·
423 Posts
subxt said:
Hi everyone, I'm not trying to jack this tread, but simply to refresh problem that seems to be somewhat PITA to too many many Subie owners.
I have an 04' FXT and sounds like it may be having the same problem as you guys experienced. When I'd disconnected the battery, and stepped on brake ~15sec, and reconnected the sluggishness remained.
At 2-3K RPM It feels as if I'm pulling small trailer.
Q 4 "N10S"; what did you mean by: ...then reconnected the power and did a key switch on-to-reset(?)
Maybe I'm doing something wrong?
I've heard of similar things that could be part of this problem;
1.) Bad Coil Packs
2.) Dirty Fuel Sock
3.) Bad Fuel Pump or Filter
4.) Bad O2 Sensor
5.) Lack of a grounding kit


I'm somewhat disappointed/tired of something that would've never happen on my Si no matter how much I bead on it.
It has 27K, I've put so much TLC into this damn wagon; Mobil1 synthetic oil, Redline trans/diff changed and maintained since new,COBB's down-pipe, STi cbe, Perrin filter, diff/shifter KB-bushings, tires @ 40PSI, always 93 Octane gas.
What the F?
Guys I need some educated opinions on what could be the cause for this sluggishness/hesitation throughout the whole midrange rpm band.
Thanx in advance for any write ups/suggestions.

Cody
04' FXT (5mt)
subxt, you certainly aren't jacking the thread...just reviving it! My comments were simply meant to note that anytime I install a new chip in a car, particularly turbo cars, I switch the ignition on and let the car sit with ignition on for several minutes before actually starting the car. This is specifically a personal habit developed from owning too many tuned VW and Audi's. This time frame supposedly allows the ECU to perform baseline reset and recalibration. Not sure that its actually as important for Suby's but I do it anyway.

Here is a link to Vishnus ECU reset procedure:

http://forums.nasioc.com/forums/showthread.php?s=&threadid=302047
 

·
Registered
2006 RX8
Joined
·
423 Posts
Btw subxt- Do you currently have a boost gauge installed? If so whats it reading? If not, I would invest in one for sure. You have a DP and catback and this should actually cause you to see a little higher boost than stock. At any rate confirming if the boost is actually lower than it should be would be an important first step.

Jeff
 

·
Registered
04 FXT
Joined
·
291 Posts
N10S thanx for the jet response. I don't have the turbo gauge as of yet but it's on list of things to get, along with egt and maybe oil pressure and/or temp gauge (Sport-Comp edition).
I just got 17's Superlegg's, TXS Hyperflow TMIC, and Perrin up-pipe which will be put back on the market if I cannot resolve this issue.
You right it would be the easiest way to detect if there was boost deficiency by getting boost gauge. I'll try tomorrow what vishnu prescribed and go from there. I'm determined to keep this tread alive for as long as the problem continues. Thanx again for any help.

Cody
 

·
Registered
Joined
·
72 Posts
FXT with Jeckle/Hyde personality

Same problem here. My 04 XT (MT Stage1) has poor response (lag/no torque) in the same rpm range on the first to second shift, especially on cold days. I'm getting tired of having to race the engine to keep up with traffic.

One thing that has really got me confused is that it runs smoother, and with much better throttle response on warm days 60 - 85 degrees, and after a heat soak. I thought heat killed performance on turbocharged cars?

There have been a few occasions were it ran great after the tank was emptied about 1/4 full and until the point were it needed a refill.

I will be investigating the following: Faulty MAF or air intake sensor; bad FPR; weak fuel pump; clogged or misplaced fuel filter sock; and plugs.

Is there anything else I should add? What about the MAP?

Thanks for any input. It will take a while to check everything out. I'll let you know if I find anything.

RickH
 

·
Premium Member
04 XT
Joined
·
733 Posts
subxt said:
N10S thanx for the jet response. I don't have the turbo gauge as of yet but it's on list of things to get, along with egt and maybe oil pressure and/or temp gauge (Sport-Comp edition).
I just got 17's Superlegg's, TXS Hyperflow TMIC, and Perrin up-pipe which will be put back on the market if I cannot resolve this issue.
You right it would be the easiest way to detect if there was boost deficiency by getting boost gauge. I'll try tomorrow what vishnu prescribed and go from there. I'm determined to keep this tread alive for as long as the problem continues. Thanx again for any help.

Cody
I would check for boost leaks especially since you have replaced the IC and moved the couplers.

Are you tuned at all? Do you get any CEL's?
 

·
Registered
04 FXT
Joined
·
291 Posts
I’m still running stock IC w/ Perrin y-pipe. I’ve been working on my car from the get-go and I’m very thorough when it comes to doing it right the first time, and yes I checked all the hoses TURBO-IC-BOV-MAF.

It just seems like something else, why?
B/c when it first started I was looking for flabby tires, leaky trans/diff, and wheel misalignment.

The hesitation felt as if I was hauling a 400Lbs mother-in-law with a loaf of bread in hand, and rack of lamb on her lap.

Now that we’d narrowed down to the turbo and/or engine management I have to try the Vishnu trick.

The PITA is that with my current mod’s I cannot ask the dealer for help.

Keep it up guys…we will make the fat one sing!
 

·
Premium Member
2004 Forester XT
Joined
·
815 Posts
Wanted to throw in my .02-

I replaced the fuel filter around 30,000 miles and instantly got a 3psi increase in boost.

In fact, prior to the FF I had not realised my power was down like it was until I got a clean fuel filter in.

It is something worth a try for low cost.
 

·
Registered
2005 FXT
Joined
·
353 Posts
“I had this exact thing happen to my Fxt. The car was acting sluggish and I immediately noticed that the boost was down to around 6-7psi maximum. I double checked all of my boost line connections and all was good. I finally dropped my battery/power and let the capacitance bleed-off for about half an hour, then reconnected the power and did a keyswitch on-to-reset. After that, I took her for a ride and the boost was back up to the 12psi max range and the car felt normal again.”

I don’t understand, please help me out.
First, I don’t think my car is sluggish, but maybe I don’t know any better. The highest I ever see my boost gage go is .06 bar; isn’t that about 8psi?

By “dropped my battery/power” do you mean disconnect the battery? Or do you mean something else?

Then, “let the capacitance bleed-off” I had thought that the Capacitance became extinct millions of years ago. What does it mean?

“keyswitch on-to-reset” sound different than the Vishnu reset, is it?

Should I be seeing .09bar? Under what kind of driving does one achieve full boost?

Help!
 

·
Registered
04 FXT
Joined
·
291 Posts
Big props to N10S for being right on the money:clap1: . I did exactly what you set and it worked like a charm. May you genes survive for all eternity!!!

I really don’t fully understand why this is happening but if I had to guess it would go like this:
- Since out of factory Subies’ come without knock sensors, the ECU automatically detects a week, rich or lean moment, a new performance/tunning part, or simply a knock that resets the ECU to default mode (according to Shiv / Vishnu)

- By disconnecting battery and draining the system completely (emergency lights on ~1min)
Reconnect the battery back and with ignition in ON position (engine off) for about 1-2min it will do the trick. However, it may take while for the computer to learn your driving habits, so you may not experience your turbos’ full potential until sometime later in a day.
Like I said it’s odd and hard to explain/understand but it just works.
I haven’t tried the Vishnu technique yet but I may once I get the TXS TMIC in.

Ø SkiPhast thanx for your “.02 cents” it’s always good to check the fuel filter for the gas quality is not as good as it’s been.
Ø Pastor Spomer you should follow N10S directives J

***It looks like I’m all set for now, but if there is anyone else who knows the exact reason/cause for the ECU mishap, please explain…

Thanx all for input.

Cody:Banane01:
 
1 - 17 of 17 Posts
Top