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Old 08-15-2011, 10:32 AM   #26
mightymints
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Hopefully gonna test Wednesday. Is the knocking possibly because of excess fuel combustion?
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Old 08-15-2011, 01:06 PM   #27
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The only thing we know is that something is up with fueling in closed loop. It may be that fueling is being calculated incorrectly due to a bad MAF or post-MAF leak. Or it may be that the ECU is making invalid corrections to fueling because of a bad front o2. Or it may be a combination of these factors or some other mechanical issue.

It may or may not be the cause of the knock you are seeing in open loop, but it is a good place to start. We don't know what the AFR looks like in open loop without a wideband o2 sensor.

Bill
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Old 08-15-2011, 04:01 PM   #28
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Bill,

I am having a friend do a compression/leak down test soon. Just so i can understand it a little better, could you explain to me what DAM is, how it's measured, what does it affect ect. Is it safe to drive with it at 0? Also, if I were to disconnect my battery would it reset the ecu and bring the DAM back to 1 as long as i don't do any aggressive driving? I have some older logs and they all have DAM at 1, it wasn't until that WOT log that it was 0. There wasn't anything loose that i could find, but there is this clicking sound right when i would pull on the throttle cable. Once again your help is much appreciated


Jake.
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Old 08-15-2011, 04:24 PM   #29
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Originally Posted by HoTBoX111 View Post
Bill,

I am having a friend do a compression/leak down test soon. Just so i can understand it a little better, could you explain to me what DAM is, how it's measured, what does it affect ect. Is it safe to drive with it at 0? Also, if I were to disconnect my battery would it reset the ecu and bring the DAM back to 1 as long as i don't do any aggressive driving? I have some older logs and they all have DAM at 1, it wasn't until that WOT log that it was 0. There wasn't anything loose that i could find, but there is this clicking sound right when i would pull on the throttle cable. Once again your help is much appreciated


Jake.
The DAM is one of the knock responses. It determines how much timing from the "Dynamic Advance" table to add to your primary timing. For the 02-05 WRX, the DAM ranges from 0 to 16. The amount of dynamic advance applied is determined by DAM/16 for these cars. So, at 16, full dynamic advance is being applied (16/16 = 1.0), at 8, half of the dynamic advance is being applied (8/16 = 0.5) and at 0, no dynamic advance is applied.

The idea behind the DAM is to generally account for the octane gas that is put in the car. So, if someone fills up with 87 octane (which they shouldn't), the DAM will likely drop to a very low value and timing will be pulled across the board (where-ever there are non-zero values in the dynamic advance table). Of course, any causes of significant knock (or false knock) when changes to the DAM are called for can also cause the DAM to drop besides just the wrong octane gas.

When you reset the ECU, the DAM will be reset to an initial value. From the factory, for these cars, this is 8, but may be higher, depending on the OTS map (ex. 12). If your DAM is 0 (or another low value), you don't want to reset the ECU as you would go back to the initial and if this is actual knock that is occuring, that would mean you would be running more timing until the DAM dropped back down again, risking further potential damage.

Bill
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Old 08-16-2011, 05:55 PM   #30
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Bill,

I have found it! i had a ballast that fell out of the zip tie and was banging against the body. Here's a picture.



What i ended up doing was, i got a zip tie and ran it through some rubber fuel line i had for grip and put some foam on the back side of it.



I did this while i was at work and on the way home, not ONE knock once so ever, the AP said 0.0/0.0

Here's a couple logs, am i good to go?

https://docs.google.com/spreadsheet/...hl=en_US#gid=0

https://docs.google.com/spreadsheet/...hl=en_US#gid=0

https://docs.google.com/spreadsheet/...hl=en_US#gid=0
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Old 08-16-2011, 08:38 PM   #31
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Bill,

I have found it! i had a ballast that fell out of the zip tie and was banging against the body. Here's a picture.

What i ended up doing was, i got a zip tie and ran it through some rubber fuel line i had for grip and put some foam on the back side of it.

I did this while i was at work and on the way home, not ONE knock once so ever, the AP said 0.0/0.0

Here's a couple logs, am i good to go?

https://docs.google.com/spreadsheet/...hl=en_US#gid=0

https://docs.google.com/spreadsheet/...hl=en_US#gid=0

https://docs.google.com/spreadsheet/...hl=en_US#gid=0
Looks like you solved it. I would still get a WOT 3rd gear run in there (from 2500 RPM to near redline) if you can do so safely.

Bill
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Old 08-18-2011, 11:07 AM   #32
mightymints
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Well, pressure test, no leaks. The downpipe shielding is loose though. I wonder if that could be causing it. Its just weird that I get FKL at WOT.

Could it be that the loose shielding only rattles at high loads when the turbo is really working?
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Old 08-18-2011, 11:32 AM   #33
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Well, pressure test, no leaks. The downpipe shielding is loose though. I wonder if that could be causing it. Its just weird that I get FKL at WOT.

Could it be that the loose shielding only rattles at high loads when the turbo is really working?
Loose heatshield can potentially cause the ECU to report knock when none exists (i.e. false knock). But, obviously, this isn't going to cause the fuel trim issues you were seeing. It could be multiple issues with this car. I would try tackling them one at a time.

Bill
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Old 08-18-2011, 09:58 PM   #34
fistandauntilus
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Check ur uppipe heatsheild. The welds tend to break causing it to rattle around, and its not in a very accessable place so its hard to inspect casually from the engine bay. Goodluck.
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Old 08-18-2011, 09:59 PM   #35
mightymints
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Wait, sorry I was tired last night. It IS the uppipe shield thats loose. Not the downpipe. I cannt find a thread on how to remove the shielding
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Old 08-18-2011, 10:11 PM   #36
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While it is a common issue its acually a PITA to fix. U have to remove the uppipe in order to repair it. Not fun.
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Old 08-18-2011, 10:11 PM   #37
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Balls, I cant just cut it off some how?
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Old 08-18-2011, 10:14 PM   #38
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U can try but goodluck. There isn't much room in there to work on it while its attached.
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Old 08-19-2011, 08:44 AM   #39
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Old 09-04-2011, 02:21 AM   #40
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fixed

Last edited by mightymints; 10-07-2011 at 12:42 AM.
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Old 09-04-2011, 09:48 AM   #41
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Originally Posted by mightymints View Post
Well, I still need to get round to fixing my car. I got a new job as a car salesman at nissan, which has been taking up my time.

I took the car for a spin tonight though, to see whats been up with it haha. Ill post logs later. The DAM is still a consistent 1.0, but halfway through the drive I noticed the fine knock learning was a consistent 1.0 also. Weird. When I gave it some, it would go to like -0.5 and gradually return to 1.0 as the revs lowered.

I also am starting to wonder if maybe I have a blown turbo or something. I noticed that i am only pushing around 8.5 boost right now at WOT.
Fine knock learning cannot be positive when the DAM is 1.0. Likely the DAM dropped. When the DAM drops below a certain point (along with a threshold for negative fine knock learning), boost control will be disabled, which may explain the low boost.

Bill
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Old 09-04-2011, 11:35 AM   #42
mightymints
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fixed

Last edited by mightymints; 10-07-2011 at 12:43 AM.
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