DAM Drop to 0

[Blob05]

So I'll keep this as brief as I can while trying to provide enough info for a possible diagnosis.

Car in question is an 05 wrx wagon. Bought it 100% stock bout 6 months ago and had been well maintained one owner. Bought at roughly 125k miles.

Mods:
AP stage 2 ACN 91
tbe with a catted down pipe
catless up
(Ran this for several months no issues with every intention of getting a pro tune or at least e-tune)

Up until about a month ago car has driven and sounded fantastic. Then one morning I went filled up with 91 oct before work, hopped on the freeway and immediately noticed major fbk and the dam drop. Bad gas perhaps I thought but drove the 2/3 miles back home and took my truck instead.

In the meantime decided to drive very grandma style staying out of boost as much as possible until I got through most the tank. Got down to bout 1/3 tank left and filled up to full with same 91 oct. Also out worries it might be numerous other things went ahead with some maintenance:

Flushed coolant
oil change
New Mishimoto Turbo Inlet (What a pita!)
Replaced PCV
Replaced numerous radiator hoses and vacuum lines that were britle
Changed out spark plugs

Fast forward to today happy to get everything back together and eager, although worried to start her up again. Same problem. Almost immediately picks up sizable fbk, then into fbkl and then dam drop to 0. No noticeable noise from engine that I can hear.

And no I don't have a wide band afr gauge only relying on the ap. I did buy one (AEM) but haven't installed yet.

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[subaru_gc8]

go get some torco from summit and put the whole thing into your gas tank.

[Blob05]

I’ll try that, honestly forgot to put it in when my tank was low. Put a bottle in this morning with a full tank already in it so just waiting a few hours for them to settle in.

Resetting ecu and will report back when I got for a drive tonight

Went for a very short (5 mile) drive. Almost immediately got the same issue, fbk fbkl and then dam drop. This time however got a code that showed up:
P0327 Sensor 1 Circuit Low Imput
Which is the knock sensor. Could this be the cause to such erratic feedback?

I’ll be doing a bunch of research and likely finding my way to where the sensor is located to investigate.

[subaru_gc8]

Originally Posted by Blob05

I'll try that, honestly forgot to put it in when my tank was low. Put a bottle in this morning with a full tank already in it so just waiting a few hours for them to settle in.

Resetting ecu and will report back when I got for a drive tonight

Went for a very short (5 mile) drive. Almost immediately got the same issue, fbk fbkl and then dam drop. This time however got a code that showed up:
P0327 Sensor 1 Circuit Low Imput
Which is the knock sensor. Could this be the cause to such erratic feedback?

I'll be doing a bunch of research and likely finding my way to where the sensor is located to investigate.

it sure can if your knock sensor isnt working that would cause a problem. but I would be careful jus to make sure it isnt something else, if your knock was that bad you can hear it, sounds like if someone got aluminum paper and crushed it all up

[Blob05]

Not sure I understand the sensor making noise like that. Probably a me issue as I’m still new to the Subaru scene and especially the diy

Took the sensor out and it looks beat. Seen some do tests on it to check for a certain reading but by the looks of this thing and how relatively cheap they are, I’ll probably just get a new one for the peace of mind.

Thanks for the responses and any advice you have. Unfortunately I came way late to the Subaru scene and all my friends have moved on to other cars so forums is my main source of info and help, that and yt

[Blob05]

Replaced the knock sensor today. Almost zero knock now. Only thing I’ve had come up was a small 1.xx fbk.

Dam returned to 16 again. Soooo happy to finally have this running again!!! Didn’t run any wot runs yet. Hopefully when I do it all goes well.

Next up on to the AEM wideband. Then coil overs and some new tires/wheels in the spring.

[subaru_gc8]

awesome glad to hear you got it fixed