Old school tachometer, driven by aftermarket ecu? How please?

[MrSix]

Hi, not sure if this is the correct place to post this. Apologies if not. 

I have a 1980 Volvo 244. It now has a 1JZ-GE and Haltech ecu. Ignition is cop, so the original single colil is no more.

I'm trying to use the original gauges, and have been trying to make the tach signal, using a relay coil, ito imitate the old ignition coil. If anyone has done something similar, or has a helpful suggestion or can point me in the right direction. It would be very much appreciated. 

Cheers Brendon 

[Goat]

I was looking at this a few years ago with my 240z. Assuming Volvo is inductive loop setup like the Z.

I found a few guides on how to do it (i just did a quick search but couldnt find any that still had current pics etc)
There was a really good guide on a toyota forum of how to do it yourself.

I ended up just getting a MSD tach adapter.

There seem to be a few other players on the market for tach adapters these days, so the may be a cheap magic box you could use.

[kws]

I guess you could use something like this to drive the tacho if its analogue, https://spiyda.com/smiths-rvi-rvc-conversion-external-1.html You should be able to feed the tach signal from the ECU into the box, but as Goat says, there will be a few different makers of things like these now.

Im running this version of it for the Smiths tacho in the Marina, which takes the signal from the negative of the coil, does some electronic wizardry and then the needle moves, https://tasteslikepetrol.net/2021/06/project-marina-tacho-conversion/

[R3spct]

My Datsun has a haltech and running std tacho with inductive loop, i just ran the power wire for the coil, coil no1 in your case, through the inductive loop and it works mint.