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DAM and FBKC


killjoy323232
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*Apologies in advance if this is in the wrong subforum...

 

I'm gradually trying to make my OBXT less of a "polished turd", and into a competent daily driver. A couple of weeks ago, I found out the shady dealership I bought the car from had connected all of the vacuum lines completely wrong. I got that remedied, hooked the battery and my AP3 back up, and after a while, noticed my DAM is pretty low (AFAIK, less than 1 is bad). More worryingly, it looks like the ECU is pulling a little timing under boost/load.

 

I'm not great at reading datalogs, but I'm trying to learn what should be concerning vs. what's more-or-less "safe". I know the engine in this car is also unreasonably noisy (the verdict is still out on whether it's VERY excessive valve clearance or an exhaust leak), so the knock sensor could be registering the "tick" under load. I haven't heard any pre-ignition.

 

I've attached a small datalog...any insights on what you guys think would be very welcome! TIA

102521 morning.csv

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How long has the DAM been that low? Usually after a reset the ECU takes some time to climb back to 1.00 Smoke test to make sure there are no vac leaks maybe best start. If You still have the original intake tube from turbo to air box they are notorious for tearing where You can't see it.
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How long has the DAM been that low? Usually after a reset the ECU takes some time to climb back to 1.00 Smoke test to make sure there are no vac leaks maybe best start. If You still have the original intake tube from turbo to air box they are notorious for tearing where You can't see it.

 

I don't think it's been that long. I vaguely remember checking it soon after the aforementioned vacuum hose (re)routing and it reading 1, then checking it again on a whim and noticed the .625. I might have that backwards, though, but I'm pretty sure it dropped. I have a very bad feeling the car was run for a LONG time with a massive vacuum leak, no FPR reference, and no BOV (This is well before I bought it - see: shady dealership). Now that it's running...well, not as poorly, I want to do everything I can to prolong the life of the motor.

 

I don't have easy access to a smoke machine, but I do know at some point, the turbo was replaced under warranty, so I can't rule the inlet out. Not sure it's been touched since then...if it is that, hopefully it's easier to do than on, say, an SG Forester XT...

 

I'll try to rig up a smoke test. Failing that, I might try the soapy water/pressurized intake method to see if I can trace a potential leak. Might have to wait until this weekend...

Edited by killjoy323232
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Bit of an update - pulled some more logs, and pored over them. It looks like a lot of my knock events are happening at part throttle (30% or so), with little to no boost (even under vacuum in some cases) right under 3000 RPM. It's pretty inconsistent, but it's pulling anywhere from 2-12 degrees. Since my fuel trims don't appear to go rich under boost, I'm going to take a second look at the pre-turbo piping this weekend, since I didn't touch that doing the vacuum line repairs.

 

I logged some pulls at part throttle and WOT, and at WOT under high boost, there's zero knock. Better still, my DAM has crept back up to 1 as of this morning.

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Might be a bad gas event. My car sometimes pulls some timing around 2300ish rpm under light loads then nothing for a few runs.

 

Could be...there's a different gas station that I can try. More and more pumps have been appearing in my city with 93, but I've had a bad tank at a different station owned by the same company. Fool me once...

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  • 2 weeks later...
Looks like I'm going to have to get a smoke test done sooner rather than later. DAM fell to .125 on my way home this evening. It's fine under boost, but lately, at part throttle - usually after I shift to 2nd or 3rd - it stumbles and pulls anywhere from 2 to 12 degrees of timing. Not sure if the stumble is due to the pulled timing, or the cause, but it's bad...
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