timing/spark advance

[Michael Vivlemore]

Looking for some input on something I have been noticing on my 2006 Chevy 2500hd 6.0 gas truck. I have a Diablo sport trinity tuner and until today I was just running their canned tune, which was doing fine. Until I started noticing the spark advance on my monitoring screen was acting erratic. It has been doing this for about a week now. With the tune installed the spark advance would jump from 14 ish to high 20 degress at idle, and be high 30's while driving, yet still erratic. Today I reverted back to factory settings to see if the spark advance would smooth out. It did not. So my question is what should I expect to see spark advance wise? I understand its constantly changing when driving to make up for different factors in the timing but it shouldn't be jumping so erratically, especially at idle. As far as the pertinent mods done to the truck they include: straight intake tube, ngk iridium plugs, 11mm wires, and true dual exhaust. Nothing that should really cause an issue. So am I just being overly protective of my lady or is this a sign of something I need to address?

[dewfpo]

Your timing should not be erratic, especially at idle/constant speed/load. It will change depending on the rpm, load and engine temp. All things equal, the more you step on the gas, the more it will go down typically but it will also rise with rpm, and of course it will drop during transmission shifts and rpm drops. But those changes are predictable as you can use the accelerator and watch it change as well as shift gears. It will change at idle but slowly. I don't believe it moves very much even when the A/C compressor is kicking on or off, I'll have to check my UltraGauge next time I have the A/C on.

 

DEWFPO

[Michael Vivlemore]

Your timing should not be erratic, especially at idle/constant speed/load. It will change depending on the rpm, load and engine temp. All things equal, the more you step on the gas, the more it will go down typically but it will also rise with rpm, and of course it will drop during transmission shifts and rpm drops. But those changes are predictable as you can use the accelerator and watch it change as well as shift gears. It will change at idle but slowly. I don't believe it moves very much even when the A/C compressor is kicking on or off, I'll have to check my UltraGauge next time I have the A/C on.

 

DEWFPO

I agree with all of that, now that the factory tune has been running a little bit it is acting normal again. Still, it has me wondering if the Diablo canned tune just has shitty parameters, or is there something wrong with the timing/ignition system?

[Michael Vivlemore]

Could also be a tank of crappy gas. I did put some better stuff in the other day when I switched back to factory tune.

[athughes26]

www.diablew.com

They use the diablo system to build you a custom downloadable tune. You send him all of your specs and upgrades and what not and he builds the tune. From those I have talked to about it, he comes highly recommended. If it ends up being a problem with the canned tune, that is the rout I would go. Definitely better than getting a new programmer.