djm_e22

Your not suppose to ever have knock retard, right? As in not even on startup, close loop, open loop? Never? Right?

MikeGyver

Knock retard is when the knock sensor and knock module 'hear' predetonation (or something that happens to sound like it), and immediately pulls timing accordingly.

I'm constantly getting little blips here and there and it's not a big deal. Could be from valvetrain noise or something ratteling or whatever. On start up, the noise from the starter could rack up a massive knock count.

Continuous knock retard of over 5 degrees or so is Very dangerous when your engine is producing power (i.e. WOT).
Any knock at all during a pull is bad, this is why it's tuned out over the revs by adjusting fueling and timing etc.

shoebox

Not so. You will almost always see some at startup from the starter meshing. Occasional retard is pretty normal, as well.

SS RRR

No such thing. It's either pre-ignition or detonation. The two carry different characteristics.
Another exmaple that an engine will always need to pull timing is when there is excessive load in a high gear (ie 20mph in 5th gear and trying to accelerate).

Injuneer

You are confusing "knock retard" with actual knock. 5-deg of knock retard means the PCM is pulling 5-degrees of timing to eliminate the knock and protect the engine. You obviously need to find out why the PCM is pulling 5-deg of timing, but the simple presence of "knock retard" is not an indication that the engine is being damaged. Its an indication that the PCM is protecting the engine from damage. Knock is bad... knock retard serves a good purpose.

SSRRR already explained the difference between pre-ignition and detonation. Next thing to correct.... the knock module doesn't "hear" anything. It processes the signal from the knock sensor, to filter noise signatures that it knows are not from true knock.

Knock retard an also be caused by increasing knock count, which is not solely a response to a signal from the knock sensor. Knock count can increase, and can trigger knock retard when thePCM has seen evidience of true knock, and starts to see the engine being operated under conditions that is feels may cause knock.

In summary, knock retard should be incidental at most. Its not unusual to see an 0.10deg knock retard pop up in the middle of a scan data log.... not worth worrying about. I've seen larger knock retard numbers result from lifting throttle shifts with the M6 at WOT. But frrequent, high levels of knock retard need to be investigated to determine the cause.