Fiero Tachometer System Explained
The information in this article can be used to troubleshoot or repair your tach if you have some knowledge of electronics, but it can also be used to modify or adjust your tach if you are doing an engine conversion or try to put a backlit V6 tach into an L4 or other car. And this modification can be done by anyone who can use a soldering iron. If you find this topic interesting, read on…
General Information
The tach is used to convert the impulses generated by the ignition system into a deflection of a needle on the gauge. The needle itself (like the speedo is driven by an air core meter. The tach I took apart (from an 85GT BTW) used a proprietary GM part (Part #2505 4339) to drive the air core meter from the ignition pulses. As luck would have it, this part is pin to pin compatible with the National Semiconductor LM1819 Air-Core meter driver. This is where things became interesting…
More Here
