[Nixlimited]

Originally Posted by WolfPlayer

It's the injectors. No matter what you do, you are going to end up with some slight hesitation at very light load on warmer days. The injectors just can't fire reliably at that IPW.

All the posts on the boards everywhere lead people to believe that you can put in bigger injectors and it will run like stock with no oddities. This is 100% not true - unless you live in a cold climate and don't see stop and go traffic much.

t

I am not disagreeing, but I have established that I have a post MAF leak and this is causing my wild AFRs in situations of high vacuum. That is what I was trying to get across. I, like you, expect that highly modified cars will not run like OEM cars.

[punchycool]

I know this question has been beat to death in dozens of threads around here and elsewhere, but I'm stumped, and was looking for some help here. I've done a lot of research already.

I've had my 05 for about 5 weeks now, and its hesitation under 3500 revs is driving me nuts. That's the only time the car bucks or complains, and this thread's discussion of the throttle plate as the potential issue seems like a prudent culprit. The car presented this issue to me on my first test drive, but I figured whatever the issue, I could get it fixed under warranty.

I'm the 2nd owner, it's totally stock, and has just over 10K miles now.
None of my local dealers can attest to any TSB's on the matter, and I've heard everything from "heck no, it should not be doing that" to "ohh yeah, we've all got that problem" from competent techs in the field and in various boards.

I've run 4 tanks of Cenex 94+ octane from our local station, and I've reset the ECU (battery disconnect + pump brakes) twice thinking I could cure it, but nothing has changed.

Any comments for a newbie STi guy?
Does an AP actually correct this?
Are there some valuable threads out there that you could point me to?

Thanks all,
-Paul

[pt518sti]

On a stock STi you shouldn't be having any hesitation or stumbling issues.

[punchycool]

Thanks for the info...hmmm...I suppose I'll get a tech to test dive with me and go from there.

Any other comments out there? :-)

-Paul

[punchycool]

Here's an update to my dilemma...another member pinged me about this. I have been meaning to update it here.

During a quick drop by at my SUbie dealer, I found two techs at lunch and both nearly immediately spotted a missing hose clamp on the turbo end of the turbo inlet hose.
I bought the car with the Perrin piece on it, and did not even notice the lack of a clamp at that position.

I took it home, and after a bit of time was able to get a good clamp on that hose. While at it, I also repositioned the bpv crossover hose and tightened it well.
After resetting the ECU again, everything is cured!
No more hesitation at all - the extra, unmetered air was really screwing up the mixture.
My car runs like jack the bear now, and has nearly zero turbo lag, something that was boggling me since day one since I could not pinpoint what was making the thing die under 3500 revs.

I must say that other posts re: the Perrin turbo linet hose seem to match my condition - there is a noticeably large gap between the OD of the turbo coupling and the ID of the hose, making it a culprit for very poor sealing. I had to twist the crud out of that hose for about an hour to get things lined up well.
Knowing this now, I would have gone with the Samco piece myself, or left the OE piece entirely.

-Paul

[crystal_Imprezav]

FYI I have posted a revised TDC table in Wolf's previous thread. It is very similar however it has minor smoothing and reduced values like stock as rpm's rise. Havent had time to post substantial logs yet but I will get to that this week. I have been running this for a couple of weeks and it feels great and no symptoms of the rapid throttle opening as rpm's rise.

[pt518sti]

Originally Posted by punchycool

Here's an update to my dilemma...another member pinged me about this. I have been meaning to update it here.

During a quick drop by at my SUbie dealer, I found two techs at lunch and both nearly immediately spotted a missing hose clamp on the turbo end of the turbo inlet hose.
I bought the car with the Perrin piece on it, and did not even notice the lack of a clamp at that position.

I took it home, and after a bit of time was able to get a good clamp on that hose. While at it, I also repositioned the bpv crossover hose and tightened it well.
After resetting the ECU again, everything is cured!
No more hesitation at all - the extra, unmetered air was really screwing up the mixture.
My car runs like jack the bear now, and has nearly zero turbo lag, something that was boggling me since day one since I could not pinpoint what was making the thing die under 3500 revs.

I must say that other posts re: the Perrin turbo linet hose seem to match my condition - there is a noticeably large gap between the OD of the turbo coupling and the ID of the hose, making it a culprit for very poor sealing. I had to twist the crud out of that hose for about an hour to get things lined up well.
Knowing this now, I would have gone with the Samco piece myself, or left the OE piece entirely.

-Paul

Thanks for the follow up.
I also have the Perrin turbo inlet and I was wondering if there would be any way you could post some pics of the exact connection that was giving you problems?
I want to double check mine and make sure everything is ok with mine
Thanks

PS: my car is running good, but I'm just curious..

[punchycool]

I know I've totally hijacked this thread - sorry about that...


Here are the pics for you, pt518sti -->
http://www.imagestation.com/album/in...?id=2100322234

Note the large clamp that puts the squeeze between the inlet flange on the turbo and the turbo inlet hose. I was missing this clamp entirely, and did not even realize it.

Note the sweet red tape over the red elbow hose between the ypipe on the intercooler and the turbo outlet...use of the wrong hose clamps will mar the hose and shred it like it did this one. I obviously need to replace the clamp with a solid clamp soon so it does not happen to the Perrin hose as well. Due to poor installation, I need to replace this red elbow hose as well as the pbv crossover hose , since it too is starting to shred the hose with the sharp hose clamp.

my 2cents,
-Paul

[pt518sti]

Originally Posted by punchycool

I know I've totally hijacked this thread - sorry about that...


Here are the pics for you, pt518sti -->
http://www.imagestation.com/album/in...?id=2100322234

Note the large clamp that puts the squeeze between the inlet flange on the turbo and the turbo inlet hose. I was missing this clamp entirely, and did not even realize it.

Note the sweet red tape over the red elbow hose between the ypipe on the intercooler and the turbo outlet...use of the wrong hose clamps will mar the hose and shred it like it did this one. I obviously need to replace the clamp with a solid clamp soon so it does not happen to the Perrin hose as well. Due to poor installation, I need to replace this red elbow hose as well as the pbv crossover hose , since it too is starting to shred the hose with the sharp hose clamp.

my 2cents,
-Paul

Thank you for the pics
So basically the Perrin inlet hose was not fully on the turbo inlet?