diagnostic help

[lord flashheart]

so i got an EJ25D in a 99 outback.
every time i snap the throttle open it almost trips over itself and shutters before it will go.
it does it more when its cold. and only if i punch the throttle open quickly.
im not getting any OBDII codes. i checked to see if it was some bizarre misfire.
but no such luck. it idles nice and runs smooth which leads me to believe it may be a
Throttle Position Sensor.
does anyone have any other ideas?

[Brockley]

so i got an EJ25D in a 99 outback.
every time i snap the throttle open it almost trips over itself and shutters before it will go.
it does it more when its cold. and only if i punch the throttle open quickly.
im not getting any OBDII codes. i checked to see if it was some bizarre misfire.
but no such luck. it idles nice and runs smooth which leads me to believe it may be a
Throttle Position Sensor.
does anyone have any other ideas?

Ditto... mine just started about a month ago. Cleaned the MAF, Cleaned the K&N, no Codes, nothing else has changed.

Thinking Fuel Pump/pressure Reg, or TPS maybe?

[Huffer]

Explain what "snapping" the throttle open is? With that description I'd have thought you were putting pedal to floor in a WOT fashion, yet you also mention WOT later.

[lord flashheart]

If you open the throttle slowly every thing is fine
but if i go wide open throttle to quickly it will it will choke
in normal driving conditions its fine but if i floor it from a stand still
the engine will shutter be for it goes

[Huffer]

opening the throttle slowly isn't "snapping" it's a gradual increase on the throttle.

What are normal driving conditions vs. standing start? Most people consider a stand still at a light "normal driving conditions".

At anyrate, it sounds like a clogged fuel filter or a slow injector. Try running some injector cleaner or Seafoam in your tank and then replacing your fuel filter.

Are you auto or manual?

[lord flashheart]

opening the throttle slowly isn't "snapping" it's a gradual increase on the throttle.

What are normal driving conditions vs. standing start? Most people consider a stand still at a light "normal driving conditions".

At anyrate, it sounds like a clogged fuel filter or a slow injector. Try running some injector cleaner or Seafoam in your tank and then replacing your fuel filter.

Are you auto or manual?
its auto.
and i have replaced the fuel filter a couple months ago and i also run fuel injector cleaner thru at every oil change.the only thing that makes sense other than the TPS is a maybe a vac leak? (possibly?)

[j_saffron]

i know what you're talking about, and my car does it too. i have an automatic.
what i do is punch it twice.
floor it once and the rpms jump, floor it the second time and it will launch.

i also use this technique on the highway for passing. rather than downshifting to 3rd.

[Huffer]

Ah. For an automatic, this behaviour is normal. The older autos do not have logic built into their TCU's to allow for going WOT from what would be considered a "standing start". What you have to do, is "drag start" it - left foot brake, bring up the RPMs while the car is in D, then let go of the brake pedal.

On a highway, while rolling, the TCU has an overdrive and will sense if you have your foot to the floor for a second or so, it will kick down to bring the RPMs up. This is also normal.

The newer 4 and 5EATs shift better and quicker, but they're no Lexus IS.

[j_saffron]

What you have to do, is "drag start" it - left foot brake, bring up the RPMs while the car is in D, then let go of the brake pedal.


i've done this and it works, but i've read that its best to install a cooling system for radiator or transmission cooler to protect the transmission from damage?

[lord flashheart]

im aware of this but, its so bad that this morning i got in my car, after it idled for a few minutes i punched the gas pedal and it shuttered so much that it almost died (down to about 300 RPMs) so i let off and the computer brought up the engine speed to about 1500 RPMs, once it gets to up in tempeture its not nearly as bad but it will still hesitate for about 1-2 full seconds. it also does this in neutral when just revving.

[Huffer]

What you have to do, is "drag start" it - left foot brake, bring up the RPMs while the car is in D, then let go of the brake pedal.


i've done this and it works, but i've read that its best to install a cooling system for radiator or transmission cooler to protect the transmission from damage?

The auto cars already have a cooler built into the radiator.

I don't recommend "punching" any auto vehicle from the USDM 95-99 model range. If you do this on a regular basis then you should consider this:
http://www.importperformancetrans.com/subaruauto.shtml

[Huffer]

im aware of this but, its so bad that this morning i got in my car, after it idled for a few minutes i punched the gas pedal and it shuttered so much that it almost died (down to about 300 RPMs) so i let off and the computer brought up the engine speed to about 1500 RPMs, once it gets to up in tempeture its not nearly as bad but it will still hesitate for about 1-2 full seconds. it also does this in neutral when just revving.

Like I said - this style of driving (from what you describe) isn't what the Subaru TCU is used to seeing. The 4EAT is designed for smooth driving, not some Dukes of Hazzard style.

Basically, when you stomp the pedal the injectors open up and the TCU cannot compensate for the fast increase in fuel/air and spark, hence the bogging. You could try cleaning up ground contacts on the electrical system as that may help (it's helped the twin turbos eliminate turbo lag so anything's possible).

But I believe this is a case of operator error, not the car (if it's got good plugs, clean fuel filter and correct grade of gas).

[lord flashheart]

i think you may be underestimating the cars hesitation.
i am aware that of how my car operates normally. believe it or not i am pretty mechanically inclined.
anyways... i just took it to my friends auto shop
and he looked at it and he (master tech with 25 years of mechanic experience and he has a 98 outback 2.5 auto) said i need to check the TPS voltage. and spray my vac lines with brake cleaner and check my plugs. cuz something is not right.

[green97gt]

our 97 gt does this bog out from a stop light if you floor it, RPMS drop and the car acts confused for a few seconds, chugs...then gets going...

the 94 SVX will just burn the tires during the same throttle action
the 00 outback will just snap forward with no hesitation
the 06 legacy outback also has no hesitation issues
the 07 outback also has no hesitation issues.

so many people complain of this issue on the 95-99 legacies etc, it almost has to be a trans computer issue.

if your TPS voltages were off you would experience the same issue slowly pressing the pedal to the floor.

if you think its the TPS, hop on that voltmeter and run the throttle by hand and see what happens. it only take 5 minutes.

[lord flashheart]

our 97 gt does this bog out from a stop light if you floor it, RPMS drop and the car acts confused for a few seconds, chugs...then gets going...

the 94 SVX will just burn the tires during the same throttle action
the 00 outback will just snap forward with no hesitation
the 06 legacy outback also has no hesitation issues
the 07 outback also has no hesitation issues.

so many people complain of this issue on the 95-99 legacies etc, it almost has to be a trans computer issue.

if your TPS voltages were off you would experience the same issue slowly pressing the pedal to the floor.

if you think its the TPS, hop on that voltmeter and run the throttle by hand and see what happens. it only take 5 minutes.
yeah and thats what i have been told but the reason i am getting into it is because my mechanic friend (mentioned above) has a 98 and it doesnt seem to do it nearly as much as mine and ive never seen another car that does it as much as mine

[green97gt]

well use your friends cars that do not exhibit this problem as a control, and test your TPS, grounds, etc against the other cars.

i wouldnt bother "checking" your plugs, cause if you have them out, you might as well just replace them.

and also, running brake clean thru your vacuum lines seems awfully shade tree, at least use carb cleaner or something, or if your taking them off, just replace them as well. no sense fiddling around with cheap shit, kind of like jumping over dollars to find pennies.

i would be seriously surprised if your friends cars do not bog/hesitate/chug/whatever if the pedal is mashed to the floor from a standstill.

brake clean IS handy to locate vacuum leaks tho, so if you suspect that, just spray it around you engine bay, and if you engine stutters, bingo.

[lord flashheart]

ok thats a good idea.
but just to clarify
im not spraying in the vacc lines
he told me to spray the lines while the engine is running and if there a vac leak it will change the engine speed when i spray the leak. or something like that.

[Brockley]

It could be the front Oxygen Sensor going bad; doesn't always throw a code and can cause similar symptoms.

[lord flashheart]

thats a good point. i didnt event think of an O2 sensor.. perhaps ill check those first.
thanks for the suggestions

[patrack92314]

yes u should do exactly as ur mechanic said i am a mechanic too and i agree thats not normal . checking for vacuum leaks and ur tps voltage is a great idea . if u test ur tps with a scope u can see the waveform or u can do it with a dvom too just set it to volts and back prob the connector i am now sure wat wire and open ur throttle plate slowly with ur key on engine off and look for a drop in voltage .

[lord flashheart]

well i checked the tps voltage. nothing significant. how ever i found a small leak by some weird diafram.
so i fixed it runs normal again. but unfortunately... i was forced to sell my car today to pay off some dept...
i nearly cried cuz i love my car.... :( he is coming to pick it up tomorrow... but its not the last subaru i will own.

[patrack92314]

well i am sorry to hear but atleast its fixed now . and u didn't just believe that ur car is supposed to do that like someone wanted u to believe

[j_saffron]

and u didn't just believe that ur car is supposed to do that like someone wanted u to believe

who would want someone to believe that about their car?
i think everyone here has a genuine interest to help others the best they can. unfortunately, text isn't the easiest format in which to describe things, especially car problems.
i knew what i was suggesting wasn't the case as soon as he said:
" i punched the gas pedal and it shuttered so much that it almost died (down to about 300 RPMs) so i let off and the computer brought up the engine speed to about 1500 RPMs, once it gets to up in tempeture its not nearly as bad but it will still hesitate for about 1-2 full seconds. it also does this in neutral when just revving."
and didn't want him to believe otherwise.

[lord flashheart]

and u didn't just believe that ur car is supposed to do that like someone wanted u to believe

who would want someone to believe that about their car?
i think everyone here has a genuine interest to help others the best they can. unfortunately, text isn't the easiest format in which to describe things, especially car problems.
i knew what i was suggesting wasn't the case as soon as he said:
" i punched the gas pedal and it shuttered so much that it almost died (down to about 300 RPMs) so i let off and the computer brought up the engine speed to about 1500 RPMs, once it gets to up in tempeture its not nearly as bad but it will still hesitate for about 1-2 full seconds. it also does this in neutral when just revving."
and didn't want him to believe otherwise.
you have a great point, i think alot of details seem to get misunderstood and lost in translation.
i think everyone on here was giving the best input based opon how they inturpeted the information.

and i wanna thank everyone who posted their thoughts and comments i think we are lucky that we dont have to deal with
trolls or ass holes on this forum. everyone is so friendly and just plain awesome.

ive been looking at some other legacys for when i am ready to buy again. i think i have an idea of what im going to do for my next subie