Jump to content

Huge Knock Pulled. WTF?


Recommended Posts

So I've been having some knock issues where -3 to -5 degrees are being pulled via FBKC driving around town. I needed to head up to my buddies house in Nevada City which is about a 3.5 hour ride from my place in Santa Cruz, so I pulled five degrees of timing and threw in some NOS octane booster then headed out on the drive. Things we're fine although I kept an eye on my knock sum while cruising on the freeway. I had two instances where I saw the Knock Sum start to increase then, boom the car stared pulling HUGE timing. I'm talking -25.00. I didn't even know that could happen. This was with cruise control in 5th gear at 70mph at about 3000RPM at 68 degrees outside. So now I've made it up here, but still have a 3.5 hour drive home and want to make sure I can just limp it home.


I'm on CA 91 gas. The engine sounds great, I've never audibly heard anything weird from the engine bay while driving or while sticking my head under there while the car is idling.


2005 LGT Wagon 5MT



Cobb Stage2+ ACN91 OTS Map

Tsudo Catless DP

Catless Up


OBX Catback

Stage 2 Competition Clutch and LW Flywheel


I attached some logs that I pulled once I saw the timing being pulled. Any thoughts. I also attached a 3rd gear pull I logged about a week ago which seems to be okay.


Any input would be very appreciated!

-11.75 FBKC.csv

-9.65 FBKC.csv

3rd Gear Pull.csv

Link to comment
Share on other sites

FYI, that's FLKC, not FBKC in your logs (learned, not feedback).


Also, that's in your low-load, low RPM cell. I wonder if you had some sort of rattle or perhaps just a temporary set of bad gas to cause a ton of (false) knock. The ECU will only start removing that correction (which it already has, if you look in your second log where the knock correction has increased to ~-7deg) if you give in enough load in that cell (<3k RPM, probably around 1.2-1.5 g/rev load). If you baby it and keep the load low, the ECU won't enter fine-correction mode, and won't start adding back timing.


To be honest, I wouldn't worry about it too much. Keep an eye on it, and see if it will add back timing on its own. If it does, I'd just keep on driving happily :)

Link to comment
Share on other sites

I generally don't worry about it too much as long as it's not really pulling timing under power, and if DAM stays at 1.000.


That said, once I have my pile of parts installed and the car is in a state that I won't be screwing with it for a while, I'll be getting off the canned tune.

Link to comment
Share on other sites


This topic is now archived and is closed to further replies.

  • Create New...

Important Information

Terms of Use