I was wondering if anyone knew of a guide of how each table and slider affects the ECU. For example I am not sure what setting the initial spark advance tells the computer. In that example I mechanically set the spark timing to 10 degrees advance in TunerPro RT because of the cam I have, does setting the Initial spark to 10 degrees offset that mechanically adjustment?
I am new to tuning but the way I understand it you set your initial spark advance to what you set your mechanical timing at
idle with the est disconnected (if your distributor is controlled by the ecm). so say you set your initial timing at 10 degrees
and then set your spark advance main to 20 degrees then the ecm will add 10 degrees to your mechanical timing making it 20 degrees.
10 + 10 = 20
In my 7427 tunerpro scalars is a initial timing setting that you set to the same as you set the mechanical timing. This is added to total timing in the timing tables. In my case 12 deg.+24 deg.= 36 deg. ( Correct me if I am wrong. )Quote:
Originally Posted by Raksj04
that seems right to me, I just started tuning and though some terminology may be different that is how it is working out if I verify it with a timing light.
in my case if I look a the factory tune the factory spark advance main table is 20 degrees at idle, base timing with est wire disconnected is 6 degrees,
so the computer is adding 14 degrees to the base timing to bring total timing to 20 degrees. mine is a 7727 ecm in a 90 corvette tpi this is the stock bin
https://drive.google.com/file/d/0B5d...ew?usp=sharing for a 90 corvette, auto, 2.59 gears.
I correct my self if your 7427 is the same as my 7727 then total would be what ever you set it for, set it to 24 degrees then it would take your 10 add 14 to bring total timing to 24 degrees. bets thing you can do is verify it with a timing light.Quote:
Originally Posted by eutu1960
http://www.gearhead-efi.com/Fuel-Inj...-Loop-Off-Idle
Read the pdf in post #3. You should be able to save a copy.
Thank you this is what I was looking for.Quote:
Originally Posted by sturgillbd
So basically by setting the Initial spark to 10, it seems to offset the mechanical adjustment I made. I am trying to figure out my surge issue I have under part throttle. Man the GM TBI system is giving me so many headaches.
A datalog may give you some clues to the surge. Post your bin and a datalog and maybe we can help you figure what is going on.
Brian
After I set the initial spark back to zero, and had the EGR installed, I had a block off plate. it seems much better. I have a ramjet cam, with the TBI heads. I will upload a datalog after I make one. Resetting the initial spark seems to make the biggest improvement.
Well most of that stuff doesn't matter at the moment since my rebuilt transmission decided to give up 2nd gear,and I deploy in a few days.