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Old 09-28-2009, 10:53 AM   #1
Daluv
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Default [GD] 06 STI VACUUM Hesitation/Stutter

Hi,

I am unable to pinpoint where is the problem. So usefull help is welcome

Car: 2006 STI 60000km
Mods:

- Invidia Catted DP
- Maddad Exhaust 3'
- K&N Air filter
- GMS turbo inlet
- GMS afta-MAF hose
- walbro fuel pump
- Maddad swaintech coated header UEL

- s204 suspension
- GroupN engine mount
- Torque Solution pitch stop
- JDM v8 HEATED driver seat retrofit
- LC-1
- FHI Ti strut
- kartboy short shifter


just replace on car:

- leakdown test 2011.02.25 less than 10% of leak with 100PSI on each cylinder...
- battery 2010.01.11
- spark plugs 2010.04.10
- PCV valve 2009.08.09
- Fuel pressure regulator 2010.04.20
- Front 02 sensor 2009.10.11
- rear diff fluid 2009.10.11
- Rear 02 sensor 2010.07.12
- Forge 100% recirc BPV 2010.08.30

Symptoms: Around 2500-3000 RPM in VACCUM ( around -10PSI ) with a CONSTANT pedal input, the car is hesitating. You can see the RPM going up and down and that car bucking while cruising. This behavior is gear and speed independant but it is worse at low speed and in close loop.
It runs A1 with light pedal input or at WOT.


Software:

I have the same behavior with the PROTUNE MAP, the cobb stage 2 map and the XPT tuning map.


Hardware:

NO CEL.

PCV Valve: Replaced it 2009.08.09. No change.

MAF: Inspected and cleaned 2009.07.09. Voltage have been monitored with Romraider. No change.

Crankshaft sensor: Inspected and clean. No change.

Fuel Pump/ Fuel filter: CHANGE FOR WALBRO FUEL PUMP and oem filter 2010.04.10. NO CHANGE

Fuel Pressure regulator vaccuum hose/line: Checked

Fuel pressure regulator: Changed on 2010.04.20. NO CHANGE.

Front 02 sensor: I ran the car with the 02 sensor unplugged and I still have the same problem. Changed under warranty 2009.10.11, no change...

Grounds: Have checked the easiest one.

Transmission ground: Need to be checked.

Sparks plugs: Change for NGK Iridium One Step Colder Spark Plugs Subaru STI 06/07 [NGK-LFR7AIX] 2010.04.10

Coilpack: Inspected OK

Fuel Pump Duty table: I tried 100% and 66%. Hesitation bahavior change a bit but it is not gone.

I drove my friend 07 that has been protuned at the same time as mine and it doesnt hesitate and feel great to drive. I even consistently put down more power than the 07 on the dyno.

I have an appointment at the dealer next week. Every time the dealer is telling me that it is normal.

Is there something I overlooked or i should consider beside selling the damm car?

thanx

Mart
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Last edited by Daluv; 08-15-2011 at 01:31 PM.
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Old 09-28-2009, 11:49 AM   #2
Nuke209
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I suggest you do a compression test.

If you can, while @ idle, log roughness monitor on cyl 1-4 and let us know.
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Old 09-28-2009, 12:10 PM   #3
Daluv
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Keep in mind that at WOT, my car run A1 and reach the boost target and make more HP/TQ than a 2007 with the same exact stage 2 setup. Same dyno, same day.

Now there's might be something I dont understand with the compression test and my problems... I dont understand why a compression test in my particular? I am just trying to understand.

I logged cyl roughness (NOT at idle) and I had one hit here and there while the hesitation was happening. Sometimes, there was none.

Quote:
Originally Posted by Nuke209 View Post
I suggest you do a compression test.

If you can, while @ idle, log roughness monitor on cyl 1-4 and let us know.
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Old 09-28-2009, 01:24 PM   #4
Exodus751
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if it was protuned why don't you ask your tuner too ? maybe he has an idea or maybe you already did
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Old 09-28-2009, 01:27 PM   #5
Daluv
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Appointement is Saturday with my Tuner. It does it on the stock map as well.

I already seen BenDagenais@Ecutek (he's local to me) for troubleshooting the car without any luck...

I've been to the dealership as well.

I guess I dont have any talented Tuner around... even went to swapshop in blainville.

Mart

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Originally Posted by Exodus751 View Post
if it was protuned why don't you ask your tuner too ? maybe he has an idea or maybe you already did
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Old 04-05-2010, 09:50 AM   #6
Daluv
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Fuel Pump/ Fuel filter: NOW CHANGED 2010.04.03 - NO CHANGE still hesitating #$%@#$@#%
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Old 04-09-2010, 03:35 PM   #7
bigfishs
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I think I may have the same problem. When it gets hot and humid my car hestitates ever so slightly at 2.5-3K rpm. My car has a reflash for smiliar mods (AVO BPV, AVO exhaust with highflow cat, KN panel filter (did have intake on, but I took that off and the idle got way better when warm, but still a little bumpy when cold).

In the winter it is great for normal driving but the hesitation is there when cold, gone when hot.

I assumed it was my tune and was gonna get a protune but it looks like that didnt sort it for you.
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Old 04-09-2010, 03:38 PM   #8
Daluv
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unless the 4 tunes

- stock
- Cobb stage 2
- xpt
- protune

made the same "mistakes" ( or lack of attention )

I seriously dont think it is the tune. My next thing is the FPR and I will check all the intake plumbing. I need to clearly understand what is going on when the car is in vaccuum.

Mart

Quote:
Originally Posted by bigfishs View Post
I think I may have the same problem. When it gets hot and humid my car hestitates ever so slightly at 2.5-3K rpm. My car has a reflash for smiliar mods (AVO BPV, AVO exhaust with highflow cat, KN panel filter (did have intake on, but I took that off and the idle got way better when warm, but still a little bumpy when cold).

In the winter it is great for normal driving but the hesitation is there when cold, gone when hot.

I assumed it was my tune and was gonna get a protune but it looks like that didnt sort it for you.
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Old 04-11-2010, 02:39 AM   #9
lil'redwagon
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'08 G37 (S/C'd); '09 XF

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i'm assuming you're using the stock bpv? i only ask because vta bov's can cause hesitaion under extremely light loads (in vac). as in, just barely floating the throttle, like 2 - 5% throttle. or to put it another way, the lightest amount of throttle you could input that doesn't close the throttle plate. if it is the stock bpv, maybe take it out and clean it thoroughly to make sure it moves freely. also make sure you don't have a crack/leak on the bpv recirc hose. i'm not sure if that would show up in a vacuum leak test. it might, but it's blocked on one side by the closed bpv, so maybe not.
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Old 04-11-2010, 09:40 AM   #10
Daluv
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Yes stock bpv.

I have pressurized my intake for leaks and found none. If only I was able to create a vacuum to test it.. maybe I'd found something...

Quote:
Originally Posted by lil'redwagon View Post
i'm assuming you're using the stock bpv? i only ask because vta bov's can cause hesitaion under extremely light loads (in vac). as in, just barely floating the throttle, like 2 - 5% throttle. or to put it another way, the lightest amount of throttle you could input that doesn't close the throttle plate. if it is the stock bpv, maybe take it out and clean it thoroughly to make sure it moves freely. also make sure you don't have a crack/leak on the bpv recirc hose. i'm not sure if that would show up in a vacuum leak test. it might, but it's blocked on one side by the closed bpv, so maybe not.
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Old 04-11-2010, 09:43 PM   #11
lil'redwagon
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'08 G37 (S/C'd); '09 XF

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just take it off and rin a can of brake cleaner through it, and make sure it works smoothly. maybe there's a piece of dirt or some gunk preventing the piston from fully closing. i know that a bov/bpv can cause weird idle/vacuum problems. maybe swap with someone who doesn't have idle/vac problems.
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Old 04-11-2010, 09:46 PM   #12
kh15
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i had similar problems but not as bad. all i did was change the dbw tables in my pro tune back to the stock tables and it helped A LOT! I still feel it every once in a while but its pretty much gone
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Old 04-12-2010, 08:03 AM   #13
Daluv
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well I am running the stock DBW table... I even tried to smooth it out with no luck or effect.

Quote:
Originally Posted by kh15 View Post
i had similar problems but not as bad. all i did was change the dbw tables in my pro tune back to the stock tables and it helped A LOT! I still feel it every once in a while but its pretty much gone
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Old 04-12-2010, 09:55 PM   #14
kh15
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have you thrown any strange cel's? any cel's pending?
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Old 04-12-2010, 11:28 PM   #15
Daluv
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Nope no current or historic CEL.

Quote:
Originally Posted by kh15 View Post
have you thrown any strange cel's? any cel's pending?
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Old 04-13-2010, 05:21 PM   #16
Le Saboteur
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I'm having the exact same problem on my 2007 STi. Had a basic tune to fix the open/closed loop tables, and that's when the issue started.
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Old 04-13-2010, 05:54 PM   #17
Daluv
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your OL/CL delay is set to 0 right? Mine is.

Mart

Quote:
Originally Posted by Le Saboteur View Post
I'm having the exact same problem on my 2007 STi. Had a basic tune to fix the open/closed loop tables, and that's when the issue started.
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Old 04-13-2010, 08:30 PM   #18
sleepyfu
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May I have a copy of this map?
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Old 04-14-2010, 12:27 PM   #19
bigfishs
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Quote:
Originally Posted by Daluv View Post
your OL/CL delay is set to 0 right? Mine is.

Mart
Can someone explain what that is^^ and what DBW is?

Im going to put my stock BPV back on and see if that makes any difference.
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Old 04-15-2010, 02:42 PM   #20
lil'redwagon
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CL/OL Delay = Closed Loop/Open Loop Delay

there is a table in RomRaider for that, that you can set to 0.

DBW = Drive By Wire

my car doesn't have this, so i'm not certain how it shows up in RomRaider, but i'm assuming there's a table for it that you can copy from a stock Drive By Wire table to revert it back to stock.
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Old 06-02-2010, 10:52 PM   #21
Daluv
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did this a week ago:

Header: Stock to MAddad. No change.

Motor Mount: Change for GroupN. NO CHANGE

Pitch Stop: Change for a Torque Solution. NO CHANGE.

any more ideas I should try?

Last edited by Daluv; 06-02-2010 at 10:58 PM.
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Old 06-07-2010, 01:14 PM   #22
Phatron
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are you running opensource now? or the protune?
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Old 06-07-2010, 01:36 PM   #23
Daluv
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right now I am running an opensource protune but I have the same hesitation using cobb or xpt tuning...

heck, even Ben dagenais from Ecutek tried to troubleshoot the problem on my car... failed...

Mart

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are you running opensource now? or the protune?
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Old 06-07-2010, 02:35 PM   #24
Phatron
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Send me your rom

[email protected]
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Old 06-07-2010, 02:42 PM   #25
Daluv
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check mail.

Quote:
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Send me your rom

[email protected]
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