$42 Spark table clarification

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11-06-2013
damanx

$42 Spark table clarification

Google search revealed quite a few threads about what value the main spark table values mean in relation to actual crank value.

I don't know why I am having such a hard time understanding this, but maybe once I get it, life might be easier.

In any case, in my other thread about some data logs and the main spark table, using a 747 ecm and a modified ASDU bin, with the latest 747 adx and xdf's I am in fact seeing a matching value between the crank and the spark table.

Now there is a reply from EagleMark about this in this linked thread

Quote:

Originally Posted by EagleMark

In $42 there is no correction for main/warm spark bias in spark advance table, what you see is spark advance plus main spark bias. So comparing to data it all off by main spark bias as it's supposed to be. What you need to know is if distributor is set to zero, does timing at crank match data? If so spark table should be off by main/warm bias. 350 and V6 have a bias, BB/454 does not.

I fixed it in next release. You will see actual in SB or BB.

If I am reading the above in yellow correctly, then if my spark table shows a particular cell at 21 degrees, then the crank reading should be that cell plus the value 9.84 degrees for spark bias for a total of 30 degrees?

If I am reading the above in red correctly about the "next release", then the main spark table reading will match the ignition analyzer crank reading regardless of the spark bias due to the fact that the adx/xdf was written to compensate for the spark bias value as long as the initial timing value of the bin matches the actual physical timing value of the distributor.
11-07-2013
mmigacz

3 Attachment(s)

Quote:

Originally Posted by damanx

Google search revealed quite a few threads about what value the main spark table values mean in relation to actual crank value.

I don't know why I am having such a hard time understanding this, but maybe once I get it, life might be easier.

In any case, in my other thread about some data logs and the main spark table, using a 747 ecm and a modified ASDU bin, with the latest 747 adx and xdf's I am in fact seeing a matching value between the crank and the spark table.

Now there is a reply from EagleMark about this in this linked thread

If I am reading the above in yellow correctly, then if my spark table shows a particular cell at 21 degrees, then the crank reading should be that cell plus the value 9.84 degrees for spark bias for a total of 30 degrees?

If I am reading the above in red correctly about the "next release", then the main spark table reading will match the ignition analyzer crank reading regardless of the spark bias due to the fact that the adx/xdf was written to compensate for the spark bias value as long as the initial timing value of the bin matches the actual physical timing value of the distributor.

This was very confusing to me also. What I found is when using the $42.xdf mask, you have to add the warm/main spark bias to the main/warm spark table. See below the example when using the $42.xdf mask.

Attachment 5770

When I used the same bin file with the $42-1227747-V5.9.3.xdf mask (or the new mask) the main/warm spark table looked like this:

Attachment 5768

You can see that with the $42-1227747-V5.9.3.xdf mask it automaticly took out the warm/main spark bias. It appears like the cold spark table works differently (it never changed from the $42.xdf to the $42-1227747-V5.9.3.xdf mask). Maybe someone else can clarify or correct me on this?
11-08-2013
EagleMark

I'm not sure what versions I added these bias to be automatically removed by linking to the actual bias value? Since some bins are differant I had to figure out how to link to the value so it was removed properly no matter what bin.

Use View, Parameter comments and read what is in there.

As of $42-1227747-V5.9.6 (maybe ealier?) both main spark and coolant spark are actual! I've just found it easier to deal with actual numbers then always having to look for and figure in what bias is.
11-08-2013
damanx

Makes sense to do it that way, especially for someone like me who deosn't quite understand it.

I am apparently got something going on because the log into work tonight, the digital timing analyzer was off by 5-7 during cruise and then in some places, as much as 10 degrees lower than what TP was displaying in the spark advance.
11-08-2013
EagleMark

If you looked at the conversion in the XDF parameter, opened it and found the -Y and followed the hex link for Y. You would see why it works accurately on any bin opened.

EGR is good for 6*... PE spark? If higher RPM the spark slope adder?
11-08-2013
damanx

Quote:

Originally Posted by EagleMark

If you looked at the conversion in the XDF parameter, opened it and found the -Y and followed the hex link for Y. You would see why it works accurately on any bin opened.

EGR is good for 6*... PE spark? If higher RPM the spark slope adder?

Gotcha!

Going to look at a couple of things and verify some numbers. I did find out that changing the Spark Latency table does affect what you see there.

Problem is that I don't know for sure that I am using the correct latency table numbers or even the correct ICM for that matter.