fallen751

I've finally gotten around to tackling the inside of the FD after the engine rebuild. The previous owner had installed a big aftermarket tach/shift gauge and screwed it to the a-pillar. It's not really my sort of thing, so I wanted to remove it. When I was uninstalling it looked like it was connected to a fuse under the driver's side dash and it was spliced into the tach signal (trigger wheel signal?) before it got to my PowerFC. I removed the splice and wrapped it in electrical tape. I don't think this is the problem because the PowerFC commander displays what I think to be correct RPM values.

Once the old aftermarket gauge was removed, the stock tach started behaving strangely. It looks like it reads at least 2000 RPM high, and sits at 1900 when the car is completely off. When I turn the key to "acc" it reads about 400-500 RPM higher at 2400-2500 RPM. It doesn't look like the tach bounces or anything while driving, but I'm not really sure how to track down the problem. I have a multimeter and can solder so I'm not afraid of pulling the gauge out if need be.

Let me know if anyone has experienced something like this or has any tips! thanks!

rxmiles

iTrader: (11)

There is really no reason to install a aftermarket tach in our cars given that it's pretty big and centralized. Most people often do so when the stock one has failed. I had a similar issue with my tach, after testing the coils wiring etc. it came down to the tach itself. The solder joints can go bad. I ended up replacing the tach on mine with another rx7 one. One thing you can do if you feel the tach is working properly (Besides the obvious reading high issue) take the gauge cluster out, remove the cover and by hand move the needle to zero. The PO might have screwed with it in the first place. Nice to see more Colorado people