help with knock :(

Ok this "annoys me" [ Edit by moderator ], my rockers are 1.6 non-self aligning & LT4 composite covers so the rockers don't make much noise, my header gaskets don't leak, but I have the exhaust comming straight from the y-pipe to a small borla race muffler, I dunno if this would cause knock? the header gaskets are brand new & they don't leak at all, the rockers barely make any noise, the timing chain does make a whoop whoop whoop sound, but my last car had that noise from the cloyes chain & it didn't set off the KS, I also went out & got an LT4 KM & that didn't do anything, I get 12* of knock, I ZEROED it out in LT1 edit but my knock count still flys, I get knock at idle, part throttle, full throttle not as much but still do, I don't know what to do, I'm using water instead of coolant, dunno if that effect it much..

I do know that when my car was stock, under load I'd get 12* of knock but I had an exhaust manifold leak, do you guys think its exhaust related or is my KS bad? LMK guys, I tried LT1 TECH with not much help so I'm asking here now. everything is in my SIG except the LT4 KM which I installed.

Originally posted by bunker

........do you guys think its exhaust related or is my KS bad? LMK guys, I tried LT1 TECH with not much help so I'm asking here now. everything is in my SIG except the LT4 KM which I installed.

Are you saying you have all this knock you can't get rid of, but have never checked the knock sensor? The basics can be checked with a V-O-M......

Check for 4-6V on the wire from the PCM with the plug off the sensor.

Check for 1.5-3.5V from the connector to the block, with the connector on the sensor

Check for 3,300-4,500ohms from the sensor wire pin to the block with the connector unplugged.

Check for any plug wires running close to the sensor wire. The high voltage pulses will induce spurious noise in the sensor circuit.

Remove sensor and check for solids buildup in the end of the sensor. I've heard of a small chunk of RTV getting in one and totally messing things up.

Have you got any serious lifter, rod, bearing or piston noise?

How much play is there in the timing chain?

I dont' hear any noise, car seems to run great & even at WOT with 94 octane gas & 0 in the whol knock retard table for values, timing chain has very very little play, unlike the stock one that has about 1/4" of play, but yeah I heard that the less play there is the more sensitive the KS is, is that true? the noise I think is timing cover rubbing I can't tell its in every cloyes timing set LT1 I've worked on, some people dont' hear it even if you tell them but its very obvious, probably only a frequency my ears can pick up :) hehe, I'm gonna do all the checking this weekend & I'll post back with the results, thanx again Injuneer.

Matt are you using Hooker LTs and a Mufflex Y=Pipe?

If so they are notorius at "Ringing" at the same frequencey the Knock sensor listens at. Jim's car has this Problem. I built a custom Y-Pipe and do NOT have this problem.

If you check the LT1 Edit archives you can find info on it.

Good luck!

No I have SLP headers with SLP y-pipe coated, the one that came from Jim's car.

Run 104 octane gas, if you still have knock then it is false, prolly from a leak or something. If no knock with 104 then you may have a problem. Narrows the options a bit.

I'm gonna try what Injuneer said this weekend, then if all fails I"ll try finding some 104 octane gas in the area.