Tables

[DEE97GTP]

Ok, most of you have seen carputings LS1 edit, or read about it. They have it where you can edit some of the tables. I am taking it one step at a time and looking at the timing.

When you "read" the PCM, LS1 edit, displays the MAP VS RPM VS Timing table. Are the values in this table hard coded, or is it a learned value? I know that the PCM has Ltrims that are offsets for the values of MAF flow rate in calculating the flow rate, and I think it takes into account the intake air temp as well.

I was analyzing some of my autotap files last night and was trying to generate a MAP vs RPM vs Timing table. If these values are hard coded, then this method would be useful in telling you what the table contained. However, I do know the PCM learns its timing over time. Is there an offset similar to Ltrim for the timing? I know about knock retard and if there is enough, it will alter the timing over time.

Is there more than one spark table? Based on temperature etc? Is there a way to know what table your car is running on?

Also, in these tables, how are the ranges defined. LS1 edit's screen shot shows RPM in 200RPM segments, and MAP in 5KPA increments. Is this how the table looks in the PCM? It has to bread them up into ranges or the tables would be like 6000X50. I don't believe there is enough memory for all that.

Maybe if I could determine what values are in the table via autotap, it might help in recognizing them in the bin.

Maybe I am on the wrong track, just something I have been pondering.

DEE

[Keith@HPTuners]

LS1 Edit files, those #'s are static. (Hard Coded)

Autotap values are dynamic.. the PCM takes the hard coded value and applies learned value math to get the final result.

The tables in LS1 edit will look a lot like the ones in the PCM however.. rows and columns will not be marked, they just end and begin. Also, the values won't translate directly.. There is translation functions that need to be applied to convert the values to say 25 degrees.

There are several spark tables. I don't know how to determine which the PCM is using though, or perhaps a combination of both.

[Keith@HPTuners]

I did some work over the weekend regarding tables..

It's very hard to spot 32 bit tables from just looking at hex.. so I had to write a complex table locater program.. took several hours but my results amazed me..

I did find a few 32 bit tables.. ALL of them were in the beginning of the file (The code part). After analyzing the data, all but one of the tables seem to be pointers to hex locations within the file. Perhaps they are just branches.

So as of right now I don't believe any data that we'll be looking at will be in the form of a 32 bit table. There are still values that are 32 bit wiithin the code.

Most of the tables I'm finding are words, but I have found a few tables that are made up of bytes.

This is my current belief. I could be wrong tho. I'll be posting an updated 97 3.8 map on monday.

- Keith

[RoboGeek]

wont things like PE and Spark Retard still be 2D byte values?

[Guest]

Does anyone know if the spark values are in a sequential block of data within the file? If so, what size data, 2 bytes each? I assumme there is a conversion factor. Would be nice to just locate the table for now.


Thanks for any help...

[RoboGeek]

yes.. they are sequential. The ALDL cars are 8 byte (2C, 88, 6A etc) but I think the newer OBDII goes to 16 byte..

In the basics are theres a post on how to identify a table. That may help you find some of the basic stuff anyways