My friend has a 94 f2 and is trying to order an aftermarket gauge cluster for it....one of those digital ones off eBay. They are available for either a positive or negative rpm signal. Can anyone tell me which is used on the f2's? Also, has anyone used one of these clusters? Any feedback....are they junk?

 

If I remember correctly, the factory tach signal comes from the #1 coil +. I'll do some checking to verify. Also may want to check a fighter specific forum as they usually have good reviews of gauges. Cheap eBay digis included. I do know that regardless you will more then likely have to play with resistor values to smooth the needle out..

 

OK.. I would like to know for sure....if it is positive signal....so if you find an answer for certain, please post back. I found a few reviews of clusters on other sites, but no mention of positive or negative signals. Is there a way I could test it...without a lab scope?

 

According to my wiring diagram, the tach ref signal comes directly from the ignition module. It is a yellow/green stripe wire. You should find it in the larger of the two connectors that plug into the back of the gauge cluster. As far as testing for reference signal, I can only speak from cars seeing as how thats what I work on, but should be the same. Heres how to test for voltage. Connecting it should be easy enough if it runs off a ref signal. And to answer your original question, it is a positive signal.

How to find a tachometer wire with your multi-meter
1. Set the ACV or AC voltage (12V or 20V is fine.)
2. Attach the (-) probe of the meter to chassis ground.
3. Start and run the vehicle.
4. Probe the wire you suspect of being the tachometer wire with the red probe of the meter.
5. If this is the correct wire the meter will increase in voltage as the RPM increases.


hope this helps. I can try testing mine when I get home if need be.

 

Thanks! That's perfect? I will tell him so he can order it ....and we will do some testing when it gets here!! Thanks a lot for all the help!!!

 

No problem, let us know how it goes.