Hey guys. I have a 1983 Mazda RX-7 with a pile of issues. Today’s issue is my tachometer is failing intermittently. Sometimes it works perfectly, sometimes it sits in one spot without moving, sometimes it very slowly reacts to changes in revs, sometimes it’s both sluggish and off target. Seems to vary day to day.
Usually if it’s working when the engine starts, it’ll keep working for the rest of the drive, and vice versa: if it’s malfunctioning when it starts it stays messed up.
All I’ve done so far is test the lead and trailing ignition coils, as suggested by someone else. Lead is 1.5 ohms primary, 10.13k secondary. Trailing is 1.3 ohms primary and 7.46k secondary.