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Old 09-28-2011, 05:28 PM   #1
derilict
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Default Horrible stumble when cold/moderate when warm

I've searched other similar threads, but all of those have other symptoms and usually display a CEL, which mine does not.

Issue: Runs like CRAP when cold, gets better once it warms up a little. Still has a slight hesitation under light and moderate load; seems to run fine at WOT.

Car: Stock '07 WRX w/ K&N PANEL filter (not intake) and STi OEM axle-back. Currently running AP Stage 1 since the car's stock.

I've replaced the plugs, cleaned the MAF, and cleaned/re-oiled the K&N. I also checked the MAF voltage with the AP, and it rises and falls with throttle/rpm as it should (or so it appears).

Is this a tuning issue?

I was thinking the AP map was making it run richer when cold, thus the bad stumble. But I re-loaded the stock map, unmarried it, and it still does it, but not as bad. I'm just thinking, as with any "issue", if you add power the problem is exacerbated.

Ideas? Thoughts?

Thanks.
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Old 09-29-2011, 10:27 AM   #2
Cobb Tuning
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Does it idle poorly as well when cold or is the issue only present when you are driving?

Bill
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Old 09-29-2011, 11:13 AM   #3
CIATexan
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Yea, this doesn't sound like a tune issue, sounds like a mechanical issue. Especially considering you took it back to stock and your having the same issues.
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Old 09-30-2011, 09:46 AM   #4
derilict
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Quote:
Originally Posted by Cobb Tuning View Post
Does it idle poorly as well when cold or is the issue only present when you are driving?

Bill
Bill, it idles perfectly cold or hot. The ONLY time I've noticed rough idle is when returning to a stop after longer periods on the interstate running 75+. The whole damn car shakes. This particular issue is only present when under load.

Quote:
Originally Posted by CIATexan View Post
Yea, this doesn't sound like a tune issue, sounds like a mechanical issue. Especially considering you took it back to stock and your having the same issues.
I'm in agreement for the most part. I'm just trying to figure out if the reason its worse with a tune loaded is 1) because of the tune, or 2) as mentioned before, anything that produces more power with an already present issue is going to exaggerate/intensify said issue.

Thanks for the reply guys.
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Old 09-30-2011, 10:57 AM   #5
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Yeah, if it is doing it with the stock map, then you have some kind of mechanical issue. The best thing to do at this point is to get a data log when the hesitation occurs and when you have the rough idle. Try not to make it a huge log that is difficult to go through. Instead, just start the logging right before the hestitaiton (or bad idle) is occuring and end it right after.

Here's a general video on how to get started with data logging. Use the default logging set, but for your particular issue, also add "A/F Correction 1".

Bill
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Old 10-17-2011, 11:12 AM   #6
derilict
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Bill,

Got some short logs in per your direction. I'm assuming at this point I need to email the .xls logs to a tuner for analysis? I'll be honest, I only have a slight idea of what I'm looking at (and conversely, what it's SUPPOSED to look like).
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Old 10-18-2011, 09:32 AM   #7
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Quote:
Originally Posted by derilict View Post
Bill,

Got some short logs in per your direction. I'm assuming at this point I need to email the .xls logs to a tuner for analysis? I'll be honest, I only have a slight idea of what I'm looking at (and conversely, what it's SUPPOSED to look like).
Use google docs and you can post a link to your log here (just upload the original .csv file not the file you opened and saved in your speadsheet software). Make sure you set the permissions in google docs to public so anyone can view it.

Bill
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Old 11-22-2011, 06:09 PM   #8
derilict
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Didn't realize .csv was a type of .xls file.

Last edited by derilict; 11-22-2011 at 06:11 PM. Reason: just kidding
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Old 11-22-2011, 06:26 PM   #9
derilict
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Log 2

https://docs.google.com/open?id=0B8z...RkZjJkZTI4NDEy

Log 1

https://docs.google.com/open?id=0B8z...I3MjQwMTNkOTI5

I'm not sure if these are telling much, I'll try to run a couple more when it's really misbehaving.

Thanks.
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Old 11-22-2011, 06:56 PM   #10
itwasthatguy
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I would think this has to do with the avcs since they are oil drivven and cold oil would flow differently than it being hot.
I think they have oil screen filters that may need cleaning.
But I am far from a subaru expert yet lol
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Old 11-23-2011, 09:27 AM   #11
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Quote:
Originally Posted by derilict View Post
Log 2

https://docs.google.com/open?id=0B8z...RkZjJkZTI4NDEy

Log 1

https://docs.google.com/open?id=0B8z...I3MjQwMTNkOTI5

I'm not sure if these are telling much, I'll try to run a couple more when it's really misbehaving.

Thanks.
Links are not working for me (says "no preview").

Bill
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Old 11-23-2011, 04:08 PM   #12
derilict
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I noticed that too Bill. Having never used google docs, I wasn't sure if this was normal. So I just clicked "download" and "open" to view them. Let me know if I need to fark with something in google docs.
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Old 11-23-2011, 05:50 PM   #13
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clean your maf
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Old 11-23-2011, 06:22 PM   #14
Cobb Tuning
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Quote:
Originally Posted by derilict View Post
I noticed that too Bill. Having never used google docs, I wasn't sure if this was normal. So I just clicked "download" and "open" to view them. Let me know if I need to fark with something in google docs.
I'm not able to download it either. Not sure what the issue is, but you can upload the actual .csv logs at our forums (cobbforums.com). Just start a post and click on manage attachments.

Bill
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Old 11-29-2011, 08:07 PM   #15
derilict
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Hey Bill, thanks for the help.

I've created a new post over at the Cobb Forums.

http://www.cobbforums.com/forums/sho...460#post659460
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Old 11-29-2011, 08:18 PM   #16
derilict
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Quote:
Originally Posted by maxx686 View Post
clean your maf
Yup, that was the first thing I did.
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Old 11-30-2011, 10:14 AM   #17
Cobb Tuning
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Quote:
Originally Posted by derilict View Post
Hey Bill, thanks for the help.

I've created a new post over at the Cobb Forums.

http://www.cobbforums.com/forums/sho...460#post659460
Hi. I responded to your post at the cobb forums.

Bill
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