When using an ECU on older cars, the tacho may not work. This is because it is driven directly from the original coil, and requires a higher voltage to work.
The DTAFast tacho converter takes the signal from the ECU and converts it to work with these older style tachos.
Note: These only work with voltage driven tachos. They do not work with current sensing tachos such as the Smith's tachos found in S1 and S2 E-Type Jaguars.
