Rev counter pick up

[minimutly]

Hmmm, I wonder if you have an amplifier built in to your coil pack - one that takes a tiny signal from the ecu, then uses a transistor pair to switch the coil on and off? Can you scan the wiring diagram?
If this is the case it will be very difficult to make yor counter work. However, you say you"old" one works?
Need more info on both rev counters as well. Are you set on ditching the old one?

[minimutly]

Ha, this is more complicated than you think, see copied post from one of the forums, yes there is an ignitor in the coil packs, which means it's going to be difficult, and maybe the wrong pack is fitted since the early ones are hard to find:

#13  Rev Counter Not Working: post #13 Martin Y
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Posted 10 September 2013 - 03:26 PM
If the tacho has never worked since you've had the car, it's possible someone has already replaced the coil pack and used the wrong type.

The original 1.8 like yours uses 4-pin coil packs and one pin on each of the two coils feeds the tacho. The '95 onward 1.8 gets its tacho pulses from the ECU directly and the 4th pin on each coil is deleted. But the early 1.8 has a quirk where if the ignition is left on without the engine running it can start to heat the coil and eventually burn it out. That means the 4-pin coils are rarer, more expensive and hard to find. You wouldn't be the first to find 3-pin coils had been fitted instead of the proper 4-pin type.
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