TD, ZD, and RD gauge signals.

[mudnut]

G'day all. I have been researching senders and signals used to drive the speedo, tacho and ECM, so that I can (maybe) learn how to calibrate the newer gauge clusters.

I see that the ZD uses a unified meter control unit. The only signal I have found which drives the tacho comes from the ECM. The manual mentions that the crank angle sensor signal is used for injector timing and fuel injector control but is it used for the tacho signal too?

EDIT: I see the TD uses an Engine Revolution Sensor which produces an AC voltage signal, where as the TB45 and RD produce a DC signal.

[mudnut]

Bump...........

[Yendor]

Yes the tacho signal is from the ZD ECU.

Yes I believe the main input for engine RPM to the ECU is the crank sensor. But you don't want to be powering up an ECU so you can calibrate a gauge. All you would need is to replicate the signal sent from the ECU to the cluster.

[mudnut]

Thanks, mate. I was looking at the different signals. I have made tacho and speedo sig gens that suit the GQ and am looking at adapting them to suit the GU.

[Yendor]

I would expect a DC signal on the wire between the the ZD30 ECU and the instrument cluster.

[mudnut]

I would love to check out and record all of the signals in all of the different engine types using my scopemeter. The gq tacho is a square wave and the speedo a good clean sine wave.

[Yendor]

I think that is the only way to get the data you are after.

I would of expected the TD42 tacho input to the instrument cluster to have been a sine way. You learn something new everyday.

I wonder if the later model GU’s with stability control still use a sine wave for vehicle speed. I’m guessing it has now changed to a square wave.

[mudnut]

I should have said the petrol tacho signal is a square wave. I haven't had the chance to test a TD yet