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Data logger - Spark Adder Average For All Cylinders


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50 minutes ago, TravisR said:



Just a quick question, I know with the SCT data logging, when the numbers were negative it would mean the PCM is adding timing and obviously positive numbers is retarding timing.

Is this the same for the PCMtec logger?



I'm not aware of that being the case. The knock adder array negative values mean it is subtracting timing, eg there is real knock, positive means it is adding timing (though from factory they don't). This is the same as SCT/HPT.

If you log the actual timing value, then that is the real final commanded timing value.

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Ok "knock sensor spark adder" is actually a maximum limit the knock control can add back to the spark timing. Where as spark adder average for all cylinders is how much spark is being pulled due to knock. 

Knowing this I would log "spark adder average for all cylinders" only as the other one is not really useful to monitor.

Looking at your logs you are getting -3 degrees of knock retard which is too much.

If you log 

Knock Adder Cyl1

Knock Adder Cyl2


Knock Adder Cyl6

You can see which cylinder is knocking. If this is a BF/FG with 2 knock sensors this should be reasonably accurate. You can tell if you have a blocked injector etc fairly easily this way.

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Yeah I just don't know whether to trust it, I've taken bulk timing out, it even starts pulling timing while cruising with 30 degrees of spark, I'll definitely be dialing it back just to play it safe for now until I get some headphones on it. I don't have those parameters to even log, I've only got the spark adder average one.

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