Quote Originally Posted by 89Vette View Post
38-deg advance sounds about right for light load conditions and medium rpms. I'm sure you know (as I) that TPS position doesn't necessarily correspond to load conditions. Going up a hill with 25% throttle requires difference mapping than 25% throttle downhill.

Assuming the physical load on the motor didn't change drasticcally, I agree that a drop from 38 to 16 degrees (with only 3% more TPS increase) is perplexing. The only place my SBC has advance that low is in the lowest rpms for maximum load (to avoid knocking during anything resembling engine lugging.)

In a quick search thru this forum, I didn't find anyone knowing of a successful ECU reprogram. Do you know any way to hack into the fueling and/or timing tables? What tool(s) do you use to monitor the conditions you're seeing.


BTW...Interesting that you say "My bad" in Oz.
We have got as far as seeing the code. We dont know what we are looking at or what it means Need to find a Supernerd who can take the time to dig thru it. Its a Delphi but we no speekee its lingo. As a side chore we are looking for which programmable GM ECU can interface. Ign is the sticking point - the one on the Gen IV Chev V8 comes closest so far in that the crank chopper is the same, but cam position signal isnt

We have a GM Tech 2 and a bunch of other OBD tools, + the dyno can display a lot of info in real time, not to mention the 'closed road testing with professional drivers under controlled conditions' that we *cough* dont do.....