1990 155 commercial. I've been chasing this high idle now for a bit. I changed the heads to high compression and the new heads only have one wire coming out of the temp sensor( I have the white/black wire connected to the wire coming out of the head). The quickstart is not turning off even when temp comes up. I can ground the white/black wire and it will turn off (Idle lowers). I'm guessing the overheat sensor only sends a ground when it overheats. Where do I connect the white/black wire? OR what is the solution?