I think Scan Gauge II starts on "some" vehicles as old as 1994 but no older.
OBDI is for Fuel Injected models 1995 or older domestic/1993 or older Euro I believe.
2006 Jeep Liberty CRD...Founder of L.O.S.T.
OME 2.25" Lift w/ Toyo Open Country HTs 235/75/16s
ASFIR Alum Eng/Tranny/Transfercase/Fuel Skids
2002 Air Box Mod...Air Tabs (5) on Roof...(3)each behind rear windows
Partial Grill Block with Custom Air Scoop and 3" Open Catback Exhaust
Lambretta UNO150cc 4 Stroke Scooter
obd1 and 2 are almost the same thing, thier both diagnostic systems capable of storing error codes. the difference is that obd2 has a crapload more sensors and can change air fuel ratio's stuff liek that more accurately while offerign a more percise error code.
ive never heard of anything to convert while in theory its possible, but actualitys its like Mac vs PC. essentialyl the same thing but no....