The discussion revolves around the feasibility of using an older OBD1 engine in a vehicle originally designed for OBD2, particularly concerning emissions compliance. A key point raised is whether a z6 engine (OBD1) can pass emissions in an OBD2 car.
One suggested method involves using a y7 or y8 ECU (OBD2) along with a crank sensor trick, or physically installing a y7/y8 oil pan and oil pump to accommodate the crank sensor. This allows the OBD2 system to function for emissions testing. After testing, one could revert to an OBD1 ECU for regular use.
Federal regulations stipulate that engine swaps must use an engine of the same year or newer than the vehicle chassis. Installing an older engine could be considered emissions tampering unless it can be demonstrated that emissions are not negatively impacted. The original vehicle manufacturer is the definitive source for certified configurations and technical specifications.
While federal law exists, its enforcement can vary significantly at the state level. For instance, California has stringent emissions standards, whereas states like Delaware might be more lenient. In less strict states, individuals may successfully run OBD1 engines in OBD2 vehicles, passing inspections as long as the check engine light (CEL) is off and an OBD2 ECU is used during the test to ensure scanner compatibility at the OBD2 port. However, such modifications might not be compliant in stricter regions.
