After about an hour and a half of constant casual driving, my safc2 says that my engine is knocking. Engine runs and sounds fine, but this is really bothering me. It starts out saying about 3 - 5…then as I drive longer it can get all the way up to 30. If I let the engine cool for a while, and start again, I’m fine for a bit, but it comes back. It really only happens when the car is idling or at low rpm, and if I rev it up a bit, the knock goes away. What I want to know is if this is a fuel issue (leaning out due to increased temp of chamber, too little octane, etc), an oil issue (if i use a thicker oil will it keep the engine cooler), or an engine wear issue that I can’t really do anything about. I run 94 octane and 10w30 non synthetic. Oh and the car hasn’t been tuned yet, so I guess that could be it, but any insight into what’s wrong or what causes knocking would be appreciated.
There’s been plenty of talk about this on Spec V’s - the knock sensor part of the SAFC is over sensitive. Most people with normal engines get up to 30 points on the SAFC without any detectable knock - if your engine is knocking, your engine will probably pull timing and you’d definately feel that.
Knock or ping is caused by fuel igniting before the spark plug makes it explode. One of the more common causes on older engines is pockets of carbon build up in the cylinders. These carbon pockets heat up with the engine and then start causing the fuel to pre-ignite on its own, which creates the sound you hear. Not to mention it’s really quite bad for your engine.
If you’ve ever heard an engine “dieseling” after the driver turns off the ignition, that’s carbon build up in the cylinders causing that.
Well that’s a relief, thanks alot for the input!
No worries. You wouldn’t have been the first one to be freaking out about that one, I can tell you that much. 
Yeah, On carburated engines…
Yeah, On carburated engines…[/quote]
exactly. completely ot.
You guys keep forgetting I’m not used to this fuelie injekshun stuff just yet. :E
Is there a water temp setting for it? So when the water temp increases, the fuel is affected?
I would hope so, a hot engine can need more fuel to cool it down.
Should be because thats how the comp know if the engine is at running temp or not. When its cold it will run a little richer to make sure you dont have starting issues and as the temp increases and the engine gets up to normal temprature it will lean out the mixture.
Maybe try replacing the coolant temp sensor, its only about $35 and can help improve gas milage and performance if its worn out.
That’s what I’m saying. If his afc or temp sensor is out of whack, then that would cause the knock reading to increase.