does the knock sensor only listen to #3 cylinder. I have a rebuilt 22re, it runs lean on #1,#2,#4 cylinders, i have slightly lower compression on #3 by 5-7 psi. My thought is my cam lobes on #3 are toast and its running richer so the knock sensor adjusts timing until it hears #3 ping, it takes more degrees of timing to get #3 to lean out vs the other cylinders, which would explain my lean issue......

 

KS's listen for a specific hertz frequency. That frequency will resonate through the block no matter what cylinder is causing the problem. Sure, it's better to have more than one KS, but for these motors I certainly wouldn't worry about it.

 

Cast iron is pretty dense stuff, the "sound" of a detonating cylinder, any cyclinder, will propogate through the block pretty darn fast. It "listens" for detonation in any of the cylinders.

 

The only way the ECU would adjust the timing until #3 pings is if #3 pings before the others. Then the ECU would retard the timing back down to baseline- meaning #3 pings first. That would suggest #3 is lean.

The ECU does not adjust timing based on rich or lean- it only adjust the fuel mix. If #3 is running rich, it's no wonder the others are lean.

Which brings me to the question: how do you know 1, 2 & 4 are lean? and then how could #3 cause detonation / ping if it's rich?