SOT -Negative spark advance, seeing this on my VW Tiguan Options

[fixer34]

Doesn't appear to be causing a problem, just never seen (looked?) it before. Had an OBD II scanner hooked up which also does real time monitoring. Was driving around and noticed that stopped/at idle, rpm was 750-800 and spark advance was -15 (15 ATDC?). Normal around town it runs about 2000rpm and +15, peaking to +20/25 at 3000.
Redline is about 5000, haven't pushed it near that.

Also noticed when backing off, even at 1500/2000, the advance will go negative.

Is this all part of the computer controlled emissions system?

[technicalninja]

You want to really see something wild?

On a car with an ETB (electronic throttle body) the throttle will not close immediately after removing your foot from the pedal. It will stay the same or OPEN MORE during engine deceleration to reduce throttle closure mixture spike to rich.

The ECU decelerates the engine via ignition timing and injector pulse width modulation and the throttle stays OPEN a LONG time.

This is part of the programming on all of the Chrysler high output hemis. Owners HATE this as you can't "rump rump" the throttle at idle.
You can accelerate the engine quickly; it takes a long time to come back to idle.

And the first mod most folks do to those is throttle remapping to allow them to do this.

So, for noise alone, folks are willing to break Federal emission laws!

800+ hp legally and they modify for this...
(IMG:style_emoticons/default/screwy.gif) (IMG:style_emoticons/default/screwy.gif)