Hey guys, another question:

Why would I have what sounds like severe detonation when it is cold out? It has been doing it for a couple years, and I always assumed it was something in the drivetrain rattling or something, but it has been particularly bad this winter and I am starting to think it is detonation.

It only does it when it's really cold, and it gets quieter and stops as the engine warms up. It sounds like it is coming from anywhere between the center console and either of the front wheels (make a triangle, and the sound moves around that triange). Sounds like a can of bolts I guess. Really hard sound to describe, but seems to move from one side to the other based on cornering a little bit. It does it under throttle, about when you would expect the turbo to spool in the rev band (though I can't imagine the turbo is really spooling under the light throttle I use on a cold engine). I let off the throttle as soon as I hear the noise, so I don't know how long it lasts or how high it goes into the rev band, but the few times I haven't backed off it feels like the ECU backs off for me somehow.

So yeah, I have no idea what this noise is, but I don't like it.

 

Do you have a tactrix cable ? If so please check your IAM and make sure your engine hasn't been HATING you.

Also, you will probably get better answers on a Subaru forum lol.

 

You would think, but most of the subaru forums I've found just say "bring it to the dealer" or something. Maybe I'm just on the wrong ones.

I'll see if I can dig up my cable and see what it says, though I haven't poked around in that ECU much. What should I be looking for?

 

I cant imagine it would take long at all. I removed my turbo, dp, intake, manifold, and oil lines off my miata in 30 minutes.

the WRX is better because there's no plastic shroud. There's 3 bolts directly on the turbo outlet and you're halfway there...




IAM is your initial spark advance multiplier right? why would that matter when it's cold? if anything you can be more aggressive with that in winter. IIRC most people start it at .75 (25% reduction in spark table) and it bumps to 1.0 (100% spark table) after the car has been driving without any knock detected. Unless his initial value is well above 1.0, but still, if it's colder out, he should have a little extra knock suppression and it should be worse in summer?

I wish there was a cruise & non-cruise AFR table...

 

it doesn't go past 1 on 32bit cars and 16 on 16bit cars

if you had a tactrix you could easily pull a learning view screenshot that would show you if the car registered any knock in the past few times you drove it, also what your mass airflow trims look like. that would be a start. next you'd need to log it, esp when it does what you say it does.

There is. Lol not sure if srs

 

Really? I remember only seeing one AFR table and thought it was annoying since everything else has multiple tables for different load/trim situations.

 

Open it up again lazy

lol

Although it wouldn't matter much since when you're in closed loop its not really following the table anyway

 

I haven't touched the map since Aug when my laptop crashed.

 

I have a VAGCOM cable and some software to hook it up to my laptop, but I haven't connected it in a couple years so I don't remember much about it. I'll give it a try and see what I can find.

 

I'll give you a vag you can hook up into.

 

Pretty sure that won't work. I think the vag com and knockoff cables only worked for the 16 bit cars, and only for certain functions.

 

I have used it on my car before, I was able to adjust my throttle tables and stuff. I don't know what the limits of it are, but it works at least for that.

 

oh you have an 05, that makes sense

 

Yep, she's old. Still under 100k miles though.

 

Yeah I was referring to looking at learning view. This will show spark corrections , IAM, and long term corrections which can show a boost leak.

 

Ok, so I got a learning view snapshot, but I think I accidentally reset the ECU before I did. Everything was zero, and the IAM was .500. So I went and drove around for 10 minutes and tried again and everything was still zero. I'll drive it for a couple days and see if anything changes.

 

yep you reset it. either that or your car is running so bad its not even advancing to 1 so you're running limp map timing and fuel

 

If your IAM is at .5, then you have knock. Anything less than 1.0 indicates a problem. 0.5 is horrible and it will pull timing and cut boost. Do you have a boost gauge? Are you running the stock map?

 

As far as I know it is the stock map. I bought the car used and I only ever touched the throttle tables, and there is no evidence that the car was tampered with before. I still suspect that the ECU reset when I tried to read the maps with ECU Burner before using learning view. I'll drive it around a bit for a couple days and then read it again.

 

so basically post #37