I’m making the wiring for a Nissan s13 with ca18det I have a question: the original CAS wiring harness is grounded to the engine. The shield is also grounded to the engine. Can I keep it like this or do I have to use the Ecumaster Black sensor ground?
I wouldn’t change it, if its wired like that from the factory and did not break yet, then its probably okay. However I would still keep an eye on noise coming from that sensor. There is a great post on the other forum here, about ECU grounding which I recommend reading: Sensor ground/ chassis ground question | General Tuning Discussion
If you have time and want to rewire it though, it most probably would not hurt to do so.