I'm in the process of rebuilding an 86 iroc I've owned for 15 years. Put in a new engine with all new accessories and sensors. Pulled back the dash to put in a new heater core. Runs great but now the oil and temp gauges won't work. I've tried different gauges, replaced the new sensors with new ones, checked all the grounds. The oil goes to max and stays there, The water slowly climbs to max and stays there. Not sure what else to look at. Any ideas?