Re: Main spark bias

[WEG1192@aol.com]

Can anyone tell me if the term "main spark bias" in the Tunercat 7747 ECM 
constants tables is the same as the "spark reference angle" in the GMEPRO 
tables? In my stock 7747 truck bin, the main spark bias is set to 10, but I 
thought the base timing setting was 6 deg for GM engines.

Also, can anyone shed any light on how open loop tuning is affected by the 
closed loop tuning. I am tuning a 7747 to run an AMC 360 engine. I have added 
almost 40% more VE to the RPM vs. MAP table in most locations and it still 
isn't enough, but its close. But it won't run well until it gets to closed 
loop mode, so I was wondering if I need to tune the open loop first. I guess 
I don't understand the relationship between the open loop tables and closed 
loop tables. Is the ECM still using the main fuel table in open loop, but 
just adding an A/F ratio multiplier to richen the mixture a little? Can 
anyone tell me where to find info on open loop tuning or remember a 
discussion in the archives? I've searched but no luck so far.

Thanks for your help. I'm tuning my first motor and it is challenging to say 
the least.
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