hi guys.. haven.t chimed in for a while, just doing a lot of reading...I do have a couple of questions if anyone feels like responding. I have a 92 gta 5.7 tpi.
7730 ecu. 8d mask started with 1615 aujp bin. I am using GMECM edit and Data Master.
1. when looking a the main spark advance table and say I put in 30 degress advance at 4400 rpms at 100kpa
Will my total advance at that point be 30 degress or will it be 30 + my 6 degrees of
intial distributor setting for a total of 36?
2. When you guys refer to plug cuts for fuel and timing.... I know how to tell the ....rich lean part.... but how do you tell about the timing by looking at the plugs?
Thanks in advance D.

 

Plugs cuts are a carry over from the carb days.
With the DFCO, there is no need to play the cut the ignition at WOT nowadays. And even with the DFCo disabled with a little cleverness, on a VE table makes it again moot.

The biggest concern with timing and reading the plugs is looking for detonation. Usually it'll show up before much of anything else, unless you've really missed the tune. Knocking the corner off of the center electrode is one sign of too much timing or too hot of plug. Cooking the glue out from between the center electrode and porclean is another clue about too hot, and that might be from timing and fuel.

Trying to just read timing on a plug is hard to do, reading a plug is telling you about the complete chamber, and how it's doing.

 

thanks grumpy.. anyone on the timing thing?

 

in your example 6base 30 in the table ecm doe math like thius basically

lookup base = 6
remeber base is also a bias so the table really say 24

24 +6 = 30. typically as long as base on the engine and base in the code are the same the output will be what commanded via the spark table + the adders or subtractors.

 

funstick, So if I understand correctly if the main spark table says "30", that is taking into account the 6 that is stated in the code as your base timing and really adding 24 more to make the total of 30.
This is of cource not counting things like pwr enrichment spark, etc. So if I physically set my distributor at a base of 6 degrees and then in the bin tell the computer it is at 6... then if I want total timing to be say 36 degrees @ 100kpa and 4400rpms, then i put the "36" in that particular cell. Yes ,,, No?