I tried searching for this over the past few days and basically get information on setting base timing, etc. Plus now the search results state "Sorry. Search has been disabled until we can figure out how to keep it from killing the server! I am running the $8D mask. The engine is a stock 94' Suburban 350 with a TPI. I have set the base timing at 6*, at both the distributor and in the code. I am certain that the balancer and timing mark are fine. When I compare my Auto-X-Ray spark advance reading with the timing light, they match at all RPM ranges. Why would the spark timing drop to 12*-14* when the table is set to 28* in the idle range? This only happens when at operating temperature (188*- 200*). Is there a constant or table that modifies idle spark vs. temperature? I have looked and do not see anything that resembles this. When the timing drops this low at idle, it dramatically affects the idle quality (for the worse). Any guidence would be appreciated. Thanks, Ed

In Tunercat and Tunerpro there is a table called 'Closed TPS Spark Advance vs RPM' and I have found this to be what affects the timing at idle.

Hope that helps

I have been using TunerPro RT for about a week now. I had downloaded Super_8dm2.ecu and it does not list that table you mentioned. Nothing close, as far as wording goes. At least I could not find it.

So I downloaded another one called 1227730_8.ecu, and it had a table called "Closd Thrtl Main Spk Advance". The start address is 17D and it has 13 rows.

I also downloaded an ECU called 8d_v03.ecu. I really like this one because it lists most everything the others do, plus it is in degrees F. But is was also missing this table you mentioned. And it was also missing the VSS constant. But it did have a table called "Idle Spark Advance vs. Coolant Temp".

I added these two new ECU items and saved it as 8d_v04.ecu. I entered the same start address, operation, factor, etc. from the other ECU(s). It seems to be fine. Is it okay to add ECU items like this. I mean, regardless of the ECU, the start address remains constant; is that correct?

It is interesting - My main spark table (start address 36), the "Closed TPS Spark Advance vs. RPM" (start address 17D), and "Idle Spark Advance vs. Coolant Temp" (start address 1FD) are all different at the same RPM levels. How does the computer know which one to use if three are not consistant? I will harmonize these three tables. Is there any more that may control idle spark advance, or is this it?

Thank you for your help, Ed.

I have the Super_8dm1.ecu. Look for the table titled "Spark Advance Closed Throttle vs RPM"

I checked Super_8dm2.ecu as well and it's there too.

Well if my labtop still worked, I could've verified that through TunerPro

Glad someone else was able to do it

Good luck

You also have tha "Idle spark advance/retard vs rpm Error".

/N.

Not all the time, ONLY if an idle speed error is detected.....