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04-16-2021, 09:22 PM | #1 |
Scooby Newbie
Member#: 523754
Join Date: Apr 2021
Vehicle:2004 STI |
2006 WRX boost hesitation and shutters.
Hey everyone, new member here. I have had some Subaru's for about 10 years and used them for my job but never had any WRX's or turbo engine ones. Been told to stay away pretty much from a local mechanic. My son really wanted one so I ended up buying a pair of them an 04 WRXSTI and a 06 WRX.
So here I am with questions on some issues. It has a lot of upgrades on the car. Was going to post a picture with a list but couldn't figure it out at this moment. So here goes. The car seems to run but one you get some boost it is like it stutters, maybe backfires and then goes more. Seems like the boost gets up to about 10 on the Cobb then drops to almost 0 then jumps back up. Makes the car stutter and jerk. Throws some misfire codes also. I am not familiar with all the workings in the car as the turbo stuff is all new to me. Looks like it was tuned by JM Automotive in Minnesota according to the Cobb map running 91 fuel and 19 PSI. Sounds maybe like a vacuum leak but maybe not since I am new. I have a Cobb log also. Here is a quick list of what the car should have. EJ257 Block Ej255 heads VFF48 Turbo 38mm Tail EWG with Grmspeed up Pipe Turbo XS Fmic Uel Headers Invidia Downpipe Grimspeed 3 port EBC SPT Intake Perrin Turbo inlet Grimspeed internal Wastegate bracket Perrin Pitch stop Perrin Lightweight crank crank pulley Mishimoto Radiator and fan shround Mishimoto Exp tank and thermostat
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Last edited by Caldor; 04-16-2021 at 09:38 PM. |
04-17-2021, 06:57 AM | #2 |
Scooby Newbie
Member#: 492422
Join Date: Oct 2018
Chapter/Region:
Tri-State
Location: North Jersey
Vehicle:2011 STI |
Well first things first, have you checked for any vacuum and or air leaks? Also when what the the last time spark plugs were changed?
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04-17-2021, 02:11 PM | #3 |
Scooby Newbie
Member#: 523754
Join Date: Apr 2021
Vehicle:2004 STI |
Not yet, from reading some posts that is what I plan to do. Any specific places to check? Figured I would follow the airflow and see if I see anything . Like I said it is all new to me but we will see how it goes. Spark plugs are unknown also.
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04-17-2021, 02:17 PM | #4 | |
Scooby Specialist
Member#: 508105
Join Date: Nov 2019
Chapter/Region:
NWIC
Location: Greater Seattle Area
Vehicle:Link G4X flex tuned 02' EJ205 20G 6MT wagon |
Quote:
You can have a shop do it or make a boost leak tester. Also clean (or preferably replace) your maf. |
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04-17-2021, 03:13 PM | #5 |
Scooby Newbie
Member#: 492422
Join Date: Oct 2018
Chapter/Region:
Tri-State
Location: North Jersey
Vehicle:2011 STI |
Do a boost leak test, you will be surprised to see what actually leaks. There are a bunch of ways to do a boost leak test and you can even build your own if your crafty. Or you could just buy your own tester. Either way, highly recommend starting off with that and doing spark plugs.
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04-21-2021, 06:05 AM | #6 |
Scooby Newbie
Member#: 514824
Join Date: May 2020
Location: Palmdale, CA
Vehicle:2012 WRX Black |
Post some logs if you can
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04-21-2021, 08:49 PM | #7 |
Scooby Newbie
Member#: 523754
Join Date: Apr 2021
Vehicle:2004 STI |
Let me know if this works. Wasn't sure how you can show the log.
https://1drv.ms/x/s!AmnHR3a0tEDq4k4W...-h_YI?e=QGgdob |
04-21-2021, 09:40 PM | #8 |
Scooby Newbie
Member#: 246844
Join Date: May 2010
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with a car that age, try replacing your MAF sensor if you never had. every calculation the engine makes is based on that. worked wonders on my 05 LGT. better idle was especially noticeable.
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04-21-2021, 11:07 PM | #9 |
Scooby Newbie
Member#: 523754
Join Date: Apr 2021
Vehicle:2004 STI |
The previous owner replaced it within the last 6 months. I am going to double check to make sure it was the correct part number and I also bought some MAF cleaner just in case.
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04-22-2021, 03:27 AM | #10 | |
Scooby Newbie
Member#: 514824
Join Date: May 2020
Location: Palmdale, CA
Vehicle:2012 WRX Black |
Quote:
can you post another log but also log AFR, AF correction 1, Inj Duty Cycle and only log a 1-2min cruise log and then log where the issue happens. but based on your symptoms. check for boost leaks, check your coil packs, spark plugs and spark plug gap. also get the car to operating temp then take off the oil cap and check for any smoke coming out. if theres any smoke coming out then good bye engine. do a compression and leakdown test. good luck |
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04-22-2021, 11:58 AM | #11 | |
Scooby Newbie
Member#: 523754
Join Date: Apr 2021
Vehicle:2004 STI |
Quote:
1st log was car up to temp and driving 50-65mph in 5th gear 2nd log was driving in 4th gear with higher RPMS same speeds 3rd log I go on it a decent amount but it bucked pretty hard 4th log was again the same, might of got on it a little more but it was decent no bucking, might of had a bit of skip 5th log was just normal driving from a stop sign up to about 50mph. Seems like the knock on the COBB showed up more the slower I was going. Showed up a little more after the 5th log and higher numbers -6 or 8. It was lower RPMS and under 40 mph, was a few seconds. https://1drv.ms/u/s!AmnHR3a0tEDq4lE1...7tZVq?e=WqR19y |
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04-22-2021, 12:12 PM | #12 |
Scooby Newbie
Member#: 523754
Join Date: Apr 2021
Vehicle:2004 STI |
Now that I am looking at some of the logs, looks like some of the info is missing maybe that you wanted. EDIT - My bad I didn't realize I needed to go into setup to select other stuff to log. Also wondering what items to most people activate in the log?
Last edited by Caldor; 04-22-2021 at 12:23 PM. |
04-22-2021, 12:30 PM | #13 |
Scooby Specialist
Member#: 491095
Join Date: Sep 2018
Chapter/Region:
SWIC
Location: New Mexico
Vehicle:2009 STi Blue Blue |
to answer earlier question, most of the stuff that needs to be looked at is on top of the engine, some under the intake manifold, but with the front mount should be easy to access...would recommend compression test while you have plugs out, get used oil analysis to see motors health
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04-22-2021, 01:03 PM | #14 |
Scooby Newbie
Member#: 523754
Join Date: Apr 2021
Vehicle:2004 STI |
Originally Posted by MasterOfNone_ View Post
there was some pretty high and consistent knock for a short period of that log. can you post another log but also log AFR, AF correction 1, Inj Duty Cycle and only log a 1-2min cruise log and then log where the issue happens. Ok I added those items on the datalog. Car ran decent. Seems to always have a little hesitation once boost kicks in. No crazy jerking this time around. Datalogs 25-29 should be with the correct items you wanted to map. I cleared codes before all these logs today and there is no misfire code yet after both sets of log runs. Seems to take a little bit of time to pop back up. |
04-22-2021, 06:35 PM | #15 |
Scooby Newbie
Member#: 213940
Join Date: Jun 2009
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I actually came here because I'm having a similar issue.
For me it started out when I was leaving work one day. Got on it getting onto the highway and about 6K RPM I felt the power cut a bit and then shifting into 3rd the exhaust popping and a stutter feeling. It drives completely normal under 4K RPM and shifting easy. But if I put it under a load the stutter and popping exhaust comes back. When I was trying to figure out what was going on, I did get the orange check engine to flask 5 or 6 times and then go away. No codes have popped up either. I replaced the MAF with a brand new one and it didn't change anything. Last edited by Lessk-STI; 04-22-2021 at 06:49 PM. |
04-22-2021, 08:09 PM | #16 | |
Scooby Newbie
Member#: 522840
Join Date: Mar 2021
Location: California
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Quote:
when you do that, include the information about what car you have and the mileage. |
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