obd I obd II

gillt1
04-12-2006, 07:27 AM
Hi, Just purchased a 1996 z28 , what's difference between obdI and obdII, Thanks for any insight

Injuneer
04-12-2006, 09:03 AM
Basically, OBD-II adds a bunch of diagnostics to catch emissions problems...

-misfire detection using a crank sensor, including misfire counts by cylinder
-after-cat O2 sensors to measure if the cats are there and working
-O2 sensor response/switching test
-tests to verify AIR system is operating
-EVAP system flow/no flow detection
-MAF rationality test, frequency range check
-coolant time to closed loop
-more sensitive EGR flow verification
-idle speed test
-traction control excessive time on
-standardized nomenclature across brands
-standardized 16-pin ALDL connector

Most of the control strategies.... e.g. A/F ratio control.... are the same. Apparently some differences in the A4 shift logic that allows higher stall convertors.