I plugged in my OBD2 scanner today...

I got really wierd timing retard, it was like between -16 and -33, sometimes it went a little lower, but still always under zero.

This graph is from a little run (no WOT), you can see the RPM in blue and timing in pink...



Anyone knows why it's like that? Is it normal?

Thanks,

Etienne

So do you know what that value means? I don't. I'm guessing the minus means before top dead center... advanced.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

well it's the value that is read from the OBD2 scanner. I tought that 0 would mean no advance, no retard; positive = advance and negative = retard...
In the program, it's called "Ignition timing advance for #1" (www.autoenginuity.com)
According to http://www.msu.edu/~guentche/guentchev/OBD-II/int-obdii.html, it means:
"The ECM-mandated advance of the ignition timing measured at cylinder #1 in degrees. This does not include any mechanical advance."

Maybe someone can explain me how to interpret those results!

I will scan another same car this week to compare.

Also, maybe my car is CAN. I tought no W202 were CAN, but maybe... if yes, that would explain why the values are off.

Etienne

Are you sure thats not the current oil price index , sorry couldn't help myself.
The gragh doesn't seem to make much sense?? Its to eratic??