Tachometer Adapter board

[brentp]

This would be no different than a properly made home-made diode circuit.

Could you describe your problems? Does it always read low RPMs? If not, does it read exactly 1/2 RPMs when it's exhibiting the problem?

[73tii]

hello Brent,

Tach was efficient for a few weeks but the problem became more consistent over time. but yes..reading is consistently low now.

below is how I did my circuit.

[73tii]

is it possible the diode is shot? anyone?

[brentp]

We're not familiar with that circuit design- it's different than what we have, but it seems that it could work. You might want to check connections on the diodes - if all connections are good it's possible one of the diodes might need replacing. Replace both just to be sure.

Make sure you're using diodes rated for at least 400V - like a 1N4004 or equivalent.

[73tii]

found a short in the wiring which subsequently affected the tach to be lazy. All is well now. Thanks Brent.

[essexstu]

Good morning, before attacking my wiring loom, wanted to check where to place the circuitboard i just recieved. Im running a v6 with wasted spark and an after market ecu - Vi-PEC (the same as link). My tacho is a standard Ford one and expecting the 400v, but the aftermarket ecu only puts out 12v.

Understanding the circuit board needs the 3 pulses, but does it need the 3 pulses from the ecu (low voltage) or the 3 pulses after the ignition amplifier that go direct to the coils?

Many thanks

[brentp]

Hello,

The board is designed to tap off of the drive lines for the coil packs - after the ignition amplifier you have.

[essexstu]

Worked a treat thanks

[brentp]

That's great to hear! Thanks for the feedback.