I've been having this issue for a few weeks now, it seems to be slowly getting worse. It feels like a certian narrow airflow range seems to trigger a CEL which only stays lit during certian RPM ranges. I took a DSMlink datalog and something tells me there is something up with the knock sensor, here are a couple screen captures.
This is when the CEL was on during closed loop operation. As you can see the ECU is clearly pulling timing which is very noticable as a power loss. I'm guessing it's pulling timing because it's seeing knock, but I can't figure out where the knock is coming from. The oxygen sensor seems to be working fine.
For a short time during the 3rd gear pull, where the white marker is, the CEL was on.
The weird thing is that the CEL doesn't stay lit. When I try to get the DTC's nothing shows up. I am running a completely stock engine, except for a hacked MAF and an EVO exhaust manifold which was a replacement for the cracked/leaky stock manifold. All of the settings for the DSMlink are zero'ed out.
#6537, "RE: Strange knock sensor stuff going on" In response to Reply # 0
OK my Dsmlink experience is a little faded but couple things first; Is your cel hooked up to your pulled timing warning? I normally had it hooked up to come on when I was pulling more than 5 degrees. That may be happening with your cel. Also take a visual (or more like a feel) of your existing knock sensor. See if your "goo" in the sensor is running (or even in the sensor). Sure sign of bad sensor. Just a starting point.
Captain Caveman
96 RS Turbo 11.414 @ 119.62 MSNS, Crower 2 NA cams, BW366, 10.5 comp, UDP, 60mm TB, W/A intercooler, 3.55 tranny 567.9whp 430tq 97 RS NA 13.188 @ 103.87 MSnS powered 12.5 comp, Crower 3's and 219.4whp with 175tq 98 RS DD 12.5 comp on stock ECU, LTH, Crower 2's, Koni, GC, Hypercoil, DG hats 99 OZ 5sp Stocker 15.856 @ 85.97 99 GS stocker auto 17.7@77mph!
#6538, "RE: Strange knock sensor stuff going on" In response to Reply # 1 Dec-26-07 04:22 PM by Hult250R
Could be Phantom Knock. basically coming from some random engine noise thats triggered at that certain time, like an exhaust rattle or anything like that.
EDIT: Does it do it at partial throttle or full throttle? Partial throttle is a notorious place for PK to show up.
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I used to have a 420A...
'92 TSi AWD
11.8 @ 119mph 470awhp 405 ft/lb torque 30psi on E85 w/ Borg Warner S256 Turbo
#6540, "RE: Strange knock sensor stuff going on" In response to Reply # 3
maybe your lifters are noisy. my car crusing from around 2k~2500 will knock under partial throttle. most dsmlink guys will solve this by changing your knock sensor settings to ignore it up to 2500. the tricky thing is that if your turbo can make boost by 2500 then you have to be careful about things.
seriously looks like my problems i had. i replaced the lifters with newest versions. my o2 sensor was also on its way out but i doubt that had to do with the knocking.
#6541, "RE: Strange knock sensor stuff going on" In response to Reply # 4
I ended up setting the knock sensor to only be enabled above 7000 RPM's... which effectively disables it. The "problem" went away.
Yeah, it's not the best thing to do, but whatever. This car is full of quick fixes like that, it's the quick fix mobile! I guess I'm a lot more lazy than I used to be.
