Knock retard?

[Rich Z]

I'm getting a bit of knock retard logged and not sure what is going on. RPMs are not high, AFR looks good, and timing doesn't look out of whack. I've attached the latest log file, and the KRs are showing up between 6570 and 6620. It's not much, 1.1 degrees, but it concerns me anyway.

Any ideas?

[Gregs]

I'm getting a bit of knock retard logged and not sure what is going on. RPMs are not high, AFR looks good, and timing doesn't look out of whack. I've attached the latest log file, and the KRs are showing up between 6570 and 6620. It's not much, 1.1 degrees, but it concerns me anyway.

Any ideas?

I don't see any knock in that frame range. The only knock I see is at frame 9896 and its not concerning. Its only 1.1* and it doesn't have a sawtooth pattern=false knock.

[ferocity02]

Any aftermarket valvetrain? That can cause false knock.

[joecar]

I see what Gregs sees.



Real knock/detonation usually shows up as a sawtooth waveform

( PCM detects knock, PCM removes timing, knock stops, as PCM restores timing knock returns, repeats... )

altho, a single event knock is not distinguishable (since it looks like a single spike).

[Rich Z]

I don't see any knock in that frame range. The only knock I see is at frame 9896 and its not concerning. Its only 1.1* and it doesn't have a sawtooth pattern=false knock.

Well, that's odd. I definitely saw the KR at the frame rate area I mentioned when I was looking at it. I even made a note on a pad. Yet when I look at it now, yeah, it's over in the 9896 range.

Beats me....

Does this mean maybe the sensors are set a tad bit too sensitive?

[Rich Z]

Any aftermarket valvetrain? That can cause false knock.

Yes, it's a Jesel valve train on the engine.

[Rich Z]

I see what Gregs sees.



Real knock/detonation usually shows up as a sawtooth waveform

( PCM detects knock, PCM removes timing, knock stops, as PCM restores timing knock returns, repeats... )

altho, a single event knock is not distinguishable (since it looks like a single spike).

Ah, thanks for the explanation. Never having seen KR before, I had no clue about what to look for. All I could see was SOMETHING was there. So I figured I had better ask about it so I wasn't getting myself into trouble.

[Gregs]

Ah, thanks for the explanation. Never having seen KR before, I had no clue about what to look for. All I could see was SOMETHING was there. So I figured I had better ask about it so I wasn't getting myself into trouble.

no problem, better to ask then be sorry later.

I honestly wouldn't worry about 1.1* its just so small. Its the only KR shown in the log and its never repeated.

[joecar]

BTW: your log file indicates MAF DTC(s) present, confirming SD mode.

[ferocity02]

Well, that's odd. I definitely saw the KR at the frame rate area I mentioned when I was looking at it. I even made a note on a pad. Yet when I look at it now, yeah, it's over in the 9896 range.

Maybe you had the data filtered when you noted the frame range? Filtering also removes data from the charts in the dashboard.