Here's the situation that's got me stumped.


Got the car a couple months ago. Codes for knock sensor and primary O2 no signal. Ran fine overall. Butt dyno reported kinda weak for 160 hp with bolt ons though (not that I've driven another EP3, so maybe disregard that). My thinking was that ignition timing was dialed back from bad knock sensor.

Replaced knock sensor. That was fun. Melted the connector near the knock sensor while torching off the IM bracket. Stupid road salt turned bolts into bits of rust vaguely resembling bolts. Melted connector was not burned through or anything, just mushed a little. Don't think this would affect anything, but maybe it does. I don't have a problem with going back in there and bypassing the connector. Only thing I messed up so far.

No change after changing knock sensor. CEL comes back in a few seconds after being cleared.

Replaced O2 sensor. Went with an eBay special. Figured it was worth the gamble for saving $60+. After changing it there was a difference. Idled a little lower and CEL took a couple minutes to come back on after clearing. Engine now occasionally surges under 1/2 throttle acceleration. Nothing super dramatic, but certainly noticeable.

Codes now for KS, Primary O2, and a lean condition.

Thinking to test continuity between knock sensor connector and whatever pin it goes to on the ecu connector? Ideas?


Car is still drivable and is my daily. I'd like to get this fixed before too long though. Or maybe I should yank the 225k a3 and throw it in the scrap bin, replace with k24. Most expensive way around this issue


Thanks

 

No one? C'mon, someone must have a tiny scrap of knowledge to spare!

I'll provide an update I guess. Literally nothing has changed. I drive this car every day but have made no progress on the sensor connection issue. Thinking my next step is to borrow a scan tool that has data stream capabilities and see if the sensors are connected and giving messed up values, or just plain not connected.

Here's an off chance idea- could too light of an oil be letting components rattle around too much and triggering the KS? I've heard the KS is pretty sensitive. The last oil change was done by the PO and he said he used 0w-20 or something. It's probably not related whatsoever, but I'll put in some 5w-30 like it seems many have done and see if it makes a difference.

 

I've had that 02 sensor signal light on for as long as I can remember. I'm digging back really far in by brain here.. but I think the sensor was in my catalytic converter or somewhere near it. Never replaced it, I get about 28 mpg doing mainly highway driving at 70-80 mph. I guess it's ok, not great, but its good enough. I think I should get better mileage though.

I wouldn't worry about it. You get used to having the check engine light on lol.

 

What's the actual knock sensor code and what is the typical interpretation? Is it actually misfire, or the knock sensor isn't working?