I bought a handy application for my phone that connects to a Bluetooth OBD-II connector, and gives me the raw data from my car’s computer. It’s is very cool, but I have an issue:
I don’t know what my car’s optimal ranges are. For instance, what temperature should my engine coolant/Timing advance/Vacuum pressure be, exactly? Does anyone know where I can find this info? I have checked the owner’s, and Hayne’s manuals without success.
I’m looking for various vehicles- A '03 BMW 3 series, '05 Dodge Neon, '09 Chevy Tahoe.
your cars are all new enough where you cannot change any classic parameters easily. If any of them are out of the manufacturer’s specification they’ll put the check engine light on (and/or other warning lights.)
I have no plans to alter any settings, nor does my software have the capability. I merely want to know what the raw numbers are behind the idiot lights.
For a spark-ignited engine, spark advance typically ranges from 10-40 degrees BTDC.
Coolant temp when fully warmed up should be somewhere around 190 degrees F.
Manifold vacuum will vary widely depending on how hard you’re stomping on the gas. If “zero” vacuum is atmospheric pressure, then you could see something close to zero if you’ve got your foot to the floor; if you’re idling at a traffic light, expect something like 20 inches of mercury (~10 psi below atmospheric pressure).