The Parts Guy
I just have three quick questions. I'm installing a RPM switch to control the IMRC's on my 4.6L DOHC. First, where should I get the tach feed signal? I was thinking of splicing into the wire that goes to the factory tach. Second, on a 94 Mark 8, do I need to open the circuit to the IMRC control valve to open the IMRC's or do I need to close the circuit to open them? Basically, does the IMRC control valve require power to keep the IMRC's closed, or does it require power to keep the IMRC's open? Finally, does anyone know the factory rpm at which the IMRC's open?