Civic 96+ direct coil tacho signal

[Jacky Fung]

Dear All,

I tried to modify an EK civic into direct coil with G4+. Wired and config ecu. Everythings works fine that I can start engine, running smoothly. Only thing is I cannot get any tacho signal from the original cluster. I tried to config a output tacho signal from ecu. Only Defi ZD works, not the original cluster. 

Google and find that due to the signal from ecu is not enough voltage to drive the cluster. Do you have any suggestions/solution about that? I heard someone only need to key a cable from the original distributor.

 

Thx in advance.

Jacky

[Adamw]

Your tacho is what is known as a "high level" tacho. Since it was originally driven directly from the ignition coil, it needs to see about a 40V spike to trigger, the Link aux outputs are only 12V so this is not enough to drive it. 

You will need a tacho booster, you can either buy a commercially available option such as this:  https://www.ebay.com/itm/142171581596 or you can use an old relay coil to do a similar job.  I suggest you use one of the ignition outputs on the expansion loom to drive the tacho booster as the normal aux outputs have a flyback diode connected internally which can work against you.

[Jacky Fung]

Hi Adamw,

Thanks for your answer. Really useful to me and already order the booster. It was an issue for me 2 months. 

Will update once I got the result.

Have a nice weekend

Jacky

[Jacky Fung]

I would like to thx Adamw solution. It works well for me.

Really appreciate your help!!