Re: How does time meter work?
Whether it is the right wire or not depends on the how the hour meter is designed. The off-the shelf "universal" hour meters are nothing more than an electric clock that displays accummulated time rather than a 12 or 24 hour display. All they need is a switched +12 volt and ground connection. Anytime the key is in the RUN position the meter runs -- and it doesn't mater if the engine is running or not so these are more of novelty than anything since they are easily tampered with. The Suzy hour meter may be triggered by the tach signal which tells the meter the engine is indeed running so it logs accummulated time. That's a very big difference from the cheaper versions. Actually, the tach on a DFI Suzy can display the run time. The process is explained in the Suzy Service Manual. As for what a tach signal is, it is a pulse produced by the charging system. Most alternators are a 12 pole system which produces 6 pulses per engine revolution. At 5000 RPM the pulse (tach) signal line has 30,000 pulses per minute. At idle (roughly 650 rpm) that line would have 3900 pulses per minute. So in the case of Suzy, the tach signal is not powering the tach, it is merely telling it that the engine is running and the meter can now record the time. +12 volts is what powers the meter.
