ignition advance

[mcrews]

02Q45 Sport.

I run a scangauge2. It is an obd2 devise that stays plugged in all the time and gives me constant/instant data.
water temp, intake air temp, mpg, mph, volts etc.
I keep it on to help with the mpgs while i'm driving.

Especially on the long trips.

THe ignition advance gauge has shown 31-34 in the past while cruising down the highway at 60-65 w/ the cruise on. while running on pretty flat highway. with 91 octane. engine temp at 193-198.

My last trip to LA from sacramento last week, the ignition advance only was at 27-29 will at 60-65. 91 octane. cruise control on. temp 193-199. rpms 18-1900.

do you have any idea why the advance would drop dowm?
My mileage was also below what I normally get.

I had a p0720 transmission code for about 3 months but got it fixed 2 weeks ago. (the trany was in 4th all the time). Did running this way 'piss off' the ecu?

I dont have any other codes and everything else seem to be running fine.

thqnks in advance

[b20vtechb]

probly s*** gas.. try from another station.

[mcrews]

thanks, but no. that's not it.
I have just run some race gas 104 octane from 76 for that very reason and no change.
and I've probably been thru 3 tanks since leaving la 2 weekends ago.

[EMK]

Not a definite answer but the first things I would check. Plugs (lean or rich) this could steer you in the right direction to find the issue. Injectors could be dirty or have one that's Begining to fail. But the 2 things I'd check first are the knock sensors and o2 sensors I don't know if your tool will give you a readout for these. But this is where I'd think the problem would be coming from.

Hope this helps

[mcrews]

thanks!

[LEMHEAD16]

I'd also look at the coolant temp sensor.

[mcrews]

why?

. engine temp at 193-198.

temp 193-199. .

[LEMHEAD16]

Bad CTS can affect timing. Usually there are two CTS one for gauge and one for ECU. I'm not sure which sensor your OBD-11 program is reading.

[mcrews]

ill check that
thanks

[Nealoc187]

different atmospheric conditions will change the advance the ecu runs - this includes changes in elevation.

[mcrews]

fortunately the drive from la to sacramento is pretty flat on 1-5 for about 400 miles after the grapevine. I am quoting #s for the exact same route.

That's kinda why i posted. like to like but different results. I'm thinking it's a map / ecu issue and I'm just trying to narrow it down.