Multiport vs TBI, and DIS conversion.

[Canyonero]

I don't recal disabling th IAC, was it disabled in both?

Looking at $0D DIS bin, I don't see an upper and lower limit to compare. Should I bracket the upper and lower limit around the 66 degree initial advance?

The stock BIN has a max retard of -9.14, inital advance of 9.84, and max advance of 40.08. So should I set it something like max retard 46, inital advance 66, max advance 96?

[robertisaar]

i THINK that's what would be necessary. i can't remember how the C3 ECMs did spark.

[Canyonero]

If deffinately ran differently with those settings, but not well. I didn't have my timing light so I couldn't tell what it was actually doing. Loping idle, slugish throttle response before it coughed and died. Poped the previous chip back in and drove it home.

So I'd say that those numbers were not correct, but we're looking in the righ direction. I think.

[robertisaar]

http://74.125.93.132/search?q=cache:QUaHbe5ONrsJ:www.diy-efi.org/gmecm/papers/747spark.txt+747spark&cd=3&hl=en&ct=clnk&gl=us

7747 spark with a dizzy... should mostly apply since it has some good info to it.

[Canyonero]

I'm thinking there is something counterintuitive at work here, trying to wrap my head around what is actually happening...

[robertisaar]

the link i posted actually goes through the step-by-step process of how the ECM calculates the spark advance...

worst case scenario: contact RBob of TGO and he'll be able to point you in the right direction.

[Canyonero]

Ok, NOW it's working. You were exactly right, it was the max advance and retard. The retard specifically. My initial advance was set to 66 degrees, and the max retard was -9, so it was hitting the limit at 57 degrees. That's why it looked like it wasn't doing anything, it was trying to adjust the timing, but it wouldn't go past that limit. i set the max retard to -66 degrees so it could retard as far as 0 degrees BTDC, same as it was before with the initial advance was 9. And it works!

My max advance is set to 0 degrees, as it won't take a negative number. I think to have it set to the same relative value, it would have been -17 degrees, but 0 will work fine.

[robertisaar]

i can haz gold star?

[Canyonero]

Absolutely Sir! Thank you very much for helping me figure it out.

[Canyonero]

I'm still keen on upgrading that ECU, I'm going to get one.