Hi guys,

A friend in work asked me today on behalf of another friend how to wire a rev counter to his 1.6 VX Astra engine fitted in his mini. Im not familiar with the engine but the guy had said theres no coil, and the instructions for the rev counter say to connect to the coil. There is a small rev counter already fitted which works, so he joined the new rev counter to the wire going to the existing one but it didn't work. Any ideas? I don't know exactly what engine it is, but it is injection.

Cheers guys

Gazza

Doesnt the tacho feed come from the ECU on this engine?? I assume its the standard Vauxhall engine management system?

I assume its the standard ecu. Don't suppose you know what colour the wire is. Does it matter what rev counter it is or do they all work the same.

Thanks for the reply.I shall pass it on.

Gazza

My gauge mfr (ETB) asks for confirmation of the engine / ecu type when ordering.

Not sure if this is relevant, but I was given to understand that the std Vx coil input is inverted (from which the oem tacho input is driven, IIRC) compared to some of the aftermarket ones.

I seem to recall reading that the original Vx coil input pulses switch down from +12V to OV, where others' pulses are switched up from 0V to 12V. If this were correct, it would explain the behaviour you saw: the pulses to your tacho would be inverted and would therefore appear wider than expected.

Just my thoughts - some of the other Vx owners on here might be able to confirm / debunk them though.

Francis.