Myself and some people that know there **** can't figure out what the issue is. 94 M6 with 139k miles on it. Was doing a 0-93mph pass and at 93mph when I let off with datamaster recording **** hit the fan and the car starting just rolling through the knock counts at idle. Fast forward a little.

Took the car out yesterday, when you start the car it sounds about 98%, the knock count does a little, but nothing to be concerned about. Oil pressure is fine all the way around. In open loop the car goes like a raped ape. In closed loop there starts to be an audible knocking sound, can't tell where. we took the valve covers off today, put the alt back on and started the car. Rockers and **** sounded fine...rev'd and it spewed oil like expected. It doesnt knock unless its closed loop...wtf would make a nasty knock in closed loop and not open loop...I don't understand it...sounds passenger side. Anything to try would be much appreciated...nobody around here know's LT1's...its horrible...I have datamaster's software and could have whatever scanning software I need...anything to look for? I don't see anything out of the ordinary other than what I said. I have an LT4 knock module btw. Please help me.

 

Knock on the LT1 is almost always electrical, either ignition or sensors. Do any of the readings look out of whack on your scans?

And please post some more info about what exactly the engine does- such as the engine's response at idle, light/heavy foot low rpms, light/heavy foot high rpms, etc. Are you sure that the engine starts knocking as soon as it hits closed loop, or is it getting worse as it warms up?

 

It gets worse to the ear as it warms up, however performance wise it doesn't effect the cars performance until closed loop...I checked the log to confirm this. Once the car is warmed up and its in closed loop and knocking the knock counts is going up and up so when I give it throttle I get spark retard and the car is a turd. It does this at any rpm when I go WOT or close to it...I get some spark retard at partial throttle as well =\

THe only thing that I can seem to find in my logs is that in BIT Data is says engine MALF occured...I don't like that. Freescan didn't seem to want to work for me so I have no idea what else to look for, everything else seems to look ok. =\ Please help.

 

Well, real knock usually means the ignition has problems, and if you're getting knock under heavy loads, it sounds like the dist. cap is bad, so --> optispark.

I don't mean to give you the worst possible scenario, but that's what it sounds like. False knock or knock retard can be caused by a lot of things on these cars, but real knock is always either ignition, or possibly fuel...

 

heh, if I thought optispark would fix it I would do it tomorrow...but I don't think so...it was replaced like 5k miles ago, the whole thing and I haven't had any problems at all. The thing that throws me for a loop is that I hear a physical knocking somewhere because caused by god only knows what. I just can't figure it out and I cannot afford to start throwing parts at it. I mean with datalogging software and being able to try stuff I don't see why I can't figure out the problem.

 

o yeah, and once its having its fits I get spark retard when I rev it in nuetral as well.

 

on my car, the knock coming out of my valve cover was a exhaust leak. gasket was blown. really scary though because it was definitly like a knocking/clicking sound which i thought was inside the valve cover. tightened the bolts and it got less noisy. replaced gasket and all is fine.

 

yeah, I had the gasket problem to begin with, well, sorta, just the bolts were loose, so I tightened them all up a couple days ago so I know that isn't it. Im so clueless...would the optispark make a sound thats like a clicking if the rotor was blown or something...even though its only a couple months old.