I put in a cam and long tubes and was doing fine with it until a couple of days ago and SES light came on so I went got a scanner and got code 43 which on the reader said Electronic Spark Cntrol Failure? In my Haynes manual it says that it is Knock Sensor (KS) Circuit? What the heck is the knock sensor and how hard is it to change?

 

The knock sensor detects detonation in the cylinders due to spark knock. A lot of people have probs with them after they do exhaust upgrades, because of all the extra noise and vibration. The knock sensor mis-interperets that as detonation, and retards your timing to protect your engine from damage. Do a search for "LT4 Knock Sensor", and you should come up with a lot of info.

 

Thanks!

 

Actually, you need to search for "LT4 knock module".

The sensor is a small piezo microphone screwed into the block drain hole on the passenger side, that picks up the noise. The module is a filter chip that plugs into the PCM to filter out known noises that cause "false knock".

 

Dammit, I always get those two mixed up.

 

Knock sensor location. It also doubles as a coolant drain plug for the engine block.

Up close and personal.

 

if your knock sensor is bad, that sucks. Mine was a bitch to get out.. it broke that sheet metal bolt end off. I had to cut a pipe wrench so it would fit up in there, and grab it by the round part to break it free... You'll notice a HUGE difference in performance when you get it fixed and desensitized tho, so you'll have something to look forward to