DAM 0 After Attempting 3rd Gear WOT - Page 2
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This is a discussion on DAM 0 After Attempting 3rd Gear WOT within the Tuning: Electronic Engine Management forums, part of the Tech & Modifying & General Repairs category; Originally Posted by WRX309 13WREX, any update on the issue? Did you re-flash the map? Yeah, but before reflashing I ...

  1. #16
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    Quote Originally Posted by WRX309 View Post
    13WREX, any update on the issue? Did you re-flash the map?

    Yeah, but before reflashing I deleted the Stage I ACN91 map that was on the AP and downloaded the same map from the Cobb website just to make sure. I made sure to scan for CEL codes first even though the car didn't throw any when the DAM went down to 0. No codes. I also tried another Shell station and filled up on 91 before flashing. Everything checked out so I uninstalled / unmarried the AP and reinstalled again instead of reflashing.

    I took it out for a drive on the freeway, and some city driving the next day (80 - 85 degree weather). Highest count of knock was -2.8, but only when I was mashing the throttle and immediately went down to 0 after 3,000 - 3,200 RPM or so. I would get a few -1.4 when mashing the throttle at low load / RPM, but it would immediately ramp back down to 0 as soon as I depressed the throttle more and RPMs would rise.


    I don't have logs of my drive at the moment but this was from my observation monitoring the AP with pretty warm weather and some city and highway driving.
    AFR looks really good staying within -/+5%. Highest was +4.69 and idles between 0 and +0.78.
    Intake temps have been around 90-100 degrees after a long drive.
    Coolant temps 180-190 degrees driving, and 190-205 degrees idling.


    The commute this morning was completely knock free, but I don't know if that's due to the ECU still learning. Outside temps were really cool outside; about 72 degrees. The true test is the commute back home since that's when I see the most knock. When outside temps are much warmer.

    I've been told I had a combination of heatsoak and bad gas that caused my DAM to drop to 0 after that 3rd gear pull that wasn't even at 100% throttle. WRX hates Vegas weather. I guess it was a bad idea to do that pull after driving on the highway, too.

    I just flashed the ECU a few days ago, so only time will tell how long this car will go knock free, but so far so good. I have my fingers crossed.
    Last edited by 13WREX; 04-29-2014 at 11:52 AM.

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  3. #17
    Work In Progress GRBOXR's Avatar
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    How many miles do you have since the re-install? I'm not sure how long it takes the ECU to "relearn" so hopefully someone else on here with more experience can shim-in on that..

    Nonetheless, monitor your DAM on the AP on the drive home to see if it varies. According to Cobbs website they state that the "DAM will tend to vary the most immediately following a reflash or ECU Reset procedure." If the DAM is remaining consistent then you are looking good.

    Hopefully everything is A-OK and your good to go

    I'm still confused by the readings from your log as stated in one of my earlier post. When you do feel comfortable recording another log do so and post up so when can compare.

  4. #18
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    Quote Originally Posted by 13WREX View Post
    Yeah, but before reflashing I deleted the Stage I ACN91 map that was on the AP and downloaded the same map from the Cobb website just to make sure. I made sure to scan for CEL codes first even though the car didn't throw any when the DAM went down to 0. No codes. I also tried another Shell station and filled up on 91 before flashing. Everything checked out so I uninstalled / unmarried the AP and reinstalled again instead of reflashing.

    I took it out for a drive on the freeway, and some city driving the next day (80 - 85 degree weather). Highest count of knock was -2.8, but only when I was mashing the throttle and immediately went down to 0 after 3,000 - 3,200 RPM or so. I would get a few -1.4 when mashing the throttle at low load / RPM, but it would immediately ramp back down to 0 as soon as I depressed the throttle more and RPMs would rise.


    I don't have logs of my drive at the moment but this was from my observation monitoring the AP with pretty warm weather and some city and highway driving.
    AFR looks really good staying within -/+5%. Highest was +4.69 and idles between 0 and +0.78.
    Intake temps have been around 90-100 degrees after a long drive.
    Coolant temps 180-190 degrees driving, and 190-205 degrees idling.


    The commute this morning was completely knock free, but I don't know if that's due to the ECU still learning. Outside temps were really cool outside; about 72 degrees. The true test is the commute back home since that's when I see the most knock. When outside temps are much warmer.

    I've been told I had a combination of heatsoak and bad gas that caused my DAM to drop to 0 after that 3rd gear pull that wasn't even at 100% throttle. WRX hates Vegas weather. I guess it was a bad idea to do that pull after driving on the highway, too.

    I just flashed the ECU a few days ago, so only time will tell how long this car will go knock free, but so far so good. I have my fingers crossed.
    The highway thing shouldn't be a problem.

    Wherever you see knock correction, it is due to knock unless your knock sensor is loose/rattling or malfunctioning. The DAM dropping to 0 is one correction, and it is different from the other knock correction you see in terms of when it happens. It reduces timing globally. It basically means things are so wrong it can't be handled the other ways. Knock Correction Advance = (Timing Advance Maximum * (DAM)) + feedback knock correction + fine learning knock correction. It uses this "rough correction" when particular conditions are met, and when that is happening you don't see changes to the other corrections like you are looking for. It does take fine learning KC beyond a max. the previous cycle, but you won't necessarily see that if your log isn't polling fast enough or you get lucky I don't think.


    RomRaider € View topic - Subaru's knock control strategy explained

    Don't do any more pulls hard until DAM is staying at 1.

    Use up that gas and fill with good highest octane premium you can, or find some 100 like Donkey said.

    I'd be looking for air leaks in the intake tract between the MAF and the turbo, and clean the MAF. Your D cell a/f learning (if I'm thinking of the right thing in the cobb lingo) looks to be zeroed out from the reset still - I'd like to see what it was before the reset or after learning. That is the one that gets applied when you go WOT and you no longer are using the O2 sensor. Anyway, your A/F correction looks wonky and it tops out at 10. Air leaks can expand a lot when you put more vacuum on that section at higher load & RPM. You would need a wideband O2 sensor to be able to see that, but if you are sucking in air after the MAF it will go lean and you can look around for loose clamps or tears or use a boost leak tester to pressurize it (carefully follow the instructions).

    Did you overboost?
    Last edited by mycologist; 04-29-2014 at 12:39 PM.
    "From a little spark may burst a mighty flame." - Dante
    "The stitch is lost unless the thread is knotted." - Italian proverb

  5. #19
    Work In Progress GRBOXR's Avatar
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    Mycologist the logs currently posted in this thread or Pre-reset. He has not done a log since the reset.

    Thanks for the reading material BTW

  6. #20
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    Quote Originally Posted by WRX309 View Post
    Mycologist the logs currently posted in this thread or Pre-reset. He has not done a log since the reset.

    Thanks for the reading material BTW
    Yes that's correct. Those logs were before I reinstalled the Stage I ACN 91 map and started fresh. DAM was at 0 at the time, because I wanted to see if it would correct itself, but it didn't. So I drove 'till the gas tank was near empty and filled up at a different station before reinstalling the map.

    DAM has stayed at 1 since the flash and driven about 40 miles. I don't think that's enough driving for it to fully learn yet, but what do I know?

    I never overboosted or even hit full boost when I "attempted" the 3rd gear pull. I lifted off when I spotted the DAM dropping and hesitated.

    I'll check to see if any hoses or clamps came loose and have a friend check for leaks. The only thing I can think of that can contribute to this is suspension (endlinks possibly knocking against something) or heatshield. I wasn't able to bolt on 3 nuts left over when I installed the turbo blanket, and I completely forgot about them, but I wouldn't think something like that would severely cause the car to knock that would drop the DAM to 0.

    Thanks for the reading material. I know the knock sensor on these cars are not perfect, but seeing DAM at 0 not even at 100% throttle was very concerning to me.

    I'll be logging the cruise coming home since weather is warmer, but I won't be doing any pulls for awhile 'till I drive it for a few weeks and see where the ECU is at.

  7. #21
    Admiral Ackbar the 1st mycologist's Avatar
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    Quote Originally Posted by 13WREX View Post
    Yes that's correct. Those logs were before I reinstalled the Stage I ACN 91 map and started fresh. DAM was at 0 at the time, because I wanted to see if it would correct itself, but it didn't. So I drove 'till the gas tank was near empty and filled up at a different station before reinstalling the map.

    DAM has stayed at 1 since the flash and driven about 40 miles. I don't think that's enough driving for it to fully learn yet, but what do I know?

    I never overboosted or even hit full boost when I "attempted" the 3rd gear pull. I lifted off when I spotted the DAM dropping and hesitated.

    I'll check to see if any hoses or clamps came loose and have a friend check for leaks. The only thing I can think of that can contribute to this is suspension (endlinks possibly knocking against something) or heatshield. I wasn't able to bolt on 3 nuts left over when I installed the turbo blanket, and I completely forgot about them, but I wouldn't think something like that would severely cause the car to knock that would drop the DAM to 0.

    Thanks for the reading material. I know the knock sensor on these cars are not perfect, but seeing DAM at 0 not even at 100% throttle was very concerning to me.

    I'll be logging the cruise coming home since weather is warmer, but I won't be doing any pulls for awhile 'till I drive it for a few weeks and see where the ECU is at.
    Ah, ok, I thought I might have missed a step.

    So, with the fresh gas and DAM on one, and you can watch the DAM too if you are careful, go nail it in second and log it. 40 miles is enough to learn the fuel trims etc. well enough. DAM will drop instantly when the conditions are met. You only have left to see if WOT meets that, carefully. Continuing to drive it as you are will be expected to continue to produce the same results. If you don't try it, you won't ever know if it is going to happen. You might try a pull at ~10psi first if you have a boost gauge. A hill will help for that (don't try WOT on a hill at first though).
    "From a little spark may burst a mighty flame." - Dante
    "The stitch is lost unless the thread is knotted." - Italian proverb

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