Understanding DAM

So pulling apart the car a little I was looking around vac leaks and such and didnt necessarily find a vac leak but the tubing for the pcv was pretty gunked up. Cleaned a large amount of stuff out of the lines and probably could be beneficial to buy an aos. But what I did find as I'm reassembling things is the passenger side pcv hose that sits on top of the valve cover wasnt sealed. It was hardly sitting on. Figured it could have been me bumping it until I noticed some gunk around the valve cover so i think that could be an issue. Checked the knock sensor and it's good, pcv valve is good, and heat shields I'll have to look at another day as I ran out of time. Banged on the downpipe heatshields and they didnt budge so it might be the ones on the factory exhaust manifold or something. Still piecing some things back together so se will see how the car reacts here in another hour or so

The PCV hoses eventually tie to the post MAF inlet, which means it causing a vacuum leak.

 

PCV tends to get gunked up in the winter, cold weather + evaporating oil and water vapor = white gunk. I don't believe an AOS of any sort would help with that, since it would still get gunked in the hose to the AOS.

How did you check the PCV valve is good? A good way is to close one end of the tubing and try to blow through. If on one of the lines you aren’t able to blow through, then it should be good. When I replaced my PCV, air was blowing through all the lines and allowed the oil vapors to gunk up in the lines. Wouldn’t blow through on the new PCV valve. It’s not the exact way to test it but that’s how I did it. Oil consumption dropped significantly and oil pressure wasn’t as high after replacement.

I just pulled it out and shook it and listened for movement. I know it's not too legit but it was replaced about 30k ago so I figured it might be a sufficient test until I replace for good piece of mind. After going through the list and checking off the issues the car feels noticeably smoother and my calculated mpg has increased for my regular commute. That being said the car is my daily and DAM is solid at 1.000 but I'm still getting knock feedback of 6.30 in some scenarios and a fine knock learn of up to -2. Afr still ranges from -20ish to +24ish but on a wot pull the number drops to 0. Are these numbers I should be concerned about? If so what to tackle next? I know without a computer the info is as much as preferred but I'm just trying to see what I can check off the list.

 

A local shop has this machine that hooks up giant hoses to your intake and exhuast and the machine pushes an acid cleaner through the engine and clears out all the vacuum lines and injected and throttle body and such while measuring what's coming out of the tailpipe. I thought is was bs until I took my 21 year old legacy gt in and when that engine puked its head gaskets I started pulling everything apart and it was crystal clean. They only charge 150 so I might get that done as thatll get all the gunk out of my lines and clean the throttle body effectively and such, figured it might help my case.

I wouldn’t be too concerned about the knock if it’s in low load situations only (cruising, light throttle, during shifts) but if you’re getting feedback knock in boost on a flat road then that’s cause for some concern. Low load knock is pretty common.

Okay awesome, that's super super reassuring. If that's the case then the spec b is fairly healthy. Thank you all for the information and helping me get the car healthy again

A local shop has this machine that hooks up giant hoses to your intake and exhuast and the machine pushes an acid cleaner through the engine and clears out all the vacuum lines and injected and throttle body and such while measuring what's coming out of the tailpipe. I thought is was bs until I took my 21 year old legacy gt in and when that engine puked its head gaskets I started pulling everything apart and it was crystal clean. They only charge 150 so I might get that done as thatll get all the gunk out of my lines and clean the throttle body effectively and such, figured it might help my case.

 

@Dalee1104

Very intrigued by this cleaning service. Can you tell me more about this service? What is it called?

 

Thanks

The service is performed by yakima auto metrics and they specialize in import vehicles. I cant remember the exact name, at the shop it's just called like a deep engine clean or something along those lines. It mainly seems to focus on the injectors so it might be called injection cleaning? But being that it pumps in through the intake it goes through all the vacuum lines and such as well. I would imagine its similar to running seafoam only on steroids and far more efficient. While the thing is running they will give the car a couple revs and test drive it to make sure all the stuff is out of the system and the engine is running properly and then they also do a complimentary inspection and engine diagnostics. Great shop that does great work, never usually take my car to shops but if I have to I trust this one

Bringing back an oldish thread with some more questions. The car has been doing good, my route has changed so less highway miles and now that I'm in town the feedback knock never goes above -3, I try to keep my eye on it more often. With the car in sport it runs perfectly well, I can push the car a little more and notice that it functions fully well. But weirdly as soon as I put it in sport sharp the DAM decreases after a quick pull. Why is this? Tonight I put it in sport sharp for a quick little pull and sure enough DAM drops to 0.625. I ease off a little and put it back to sport and drive it some more. As the turbo spools with each acceleration the damn starts to bump back up in increments. Eventually doing a decent pull to get my psi up there and the DAM is back to 1.000. I'm not too sure what's going on. If it's worth mentioning the weather is cold here and I do remember awhile back sport sharp had let my turbo spool up to 16.7 which is over boosting is it not? Isnt the vf46 16.5 psi? Seeing the the DAM had again obviously dropped until hitting boost a few more times for it to work it's way back up. Weird thing is tonight the car only built 15.64 psi, never any more

okay so i finally got my hands on a new enough laptop and loaded the stock tune onto the spec b. i ran a datalog for a drive around the block a few times and also some quick canyon runs as thats what i use the car for most often... okay im lost, tried a few things and searched google. how exactly do i share this datalog with you guys?