My 94 Civic has recently developed a problem with the tachometer. Basically, idle rpms are represented correctly at 750 to 800 rpms, but as the needle climbs the display of rpms is not correct, rev limiter is being hit at 5500 rpms. The car is pulling all the way to the actual rev limit as first gear runs out of steam at approximately 35 mph, 2nd gear at 60 or so. It seems as if the problem is variable, as the revs climb, the tachometer displays a more and more different output than what the motor is actually turning. The rest of the gauge cluster seems to be working correctly, just the tachometer is affected.
I'm assuming that the tach displays rpms based on changing voltage which it receives from the ecu. Any ideas where to look?
