I'm still trying to nail down my Cruise Not Available and knock sensor MIL problem, and I've been scanning data while driving. One thing I noticed is that the timing advance is +10 degrees at idle, and goes up to around +35 degrees when cruising. It doesn't jump around when at a steady mph. Does anyone know if it's normal for the timing to be so advanced all the time?

Oh, and this was during one of the rare times when neither the MIL nor the Cruise message was displayed.

Thanks!

 

not sure about my jaguar, but my searay boat with gm305 v8 is 8 degrees before top dead center.

 

wjbell, let me take my car out for a drive and see if I can see what my car is doing. Then we can compare notes. Please keep in mind that the amount of timing advance is going to be dependent upon what the computer thinks it can get away with without causing pinging.

 

Thanks - I'm curious to compare! I can see the 10 degrees at idle for a higher compression engine, but 35 degrees at 45-50mph seems out-of-bounds. Maybe it's all normal, so just curious and I can't find a chart of timing vs. rpm movements.

 

It's not unusual for engine ignition timing to be advanced 50-55 degrees at higher speeds and low loads, typical of highway driving. What you're seeing is quite conservative.

 

Good. I haven't seen it get quite that advanced, but I'm also a conservative driver. Sometimes too much data is a curse...

 

wjbell, I drove my car while playing with the timing reading. My car was consistent with 10 degrees of advance at idle and staying pretty much at 36.5 degrees while cruising the highway.

 

Ours must be twins from the factory - identical advance readings! Thanks for giving me the peace of mind. Did you happen to read my latest hypothesis on my "Wit's End" post? I think I've nailed it!