Omega Owners Forum

Chat Area => General Car Chat => Topic started by: MartinP on 13 June 2011, 22:29:00

Title: Tacho reading without ABS module!!
Post by: MartinP on 13 June 2011, 22:29:00

Once again, for the kit car  :)

This is the drawing for the Tacho  :-?

(http://i3.photobucket.com/albums/y99/issunaz/Robin%20Hood/scan0003.jpg)
How do I rig this up to the V6, to give me a reading? Where do I have to pick the feed up from?

The gauge supplier got a bit vauge when I told him there were 3 coils and said "I would rather you tell me how it is going to be connected"

Any help appreciated.

Martin

Title: Re: Tacho reading without ABS module!!
Post by: Lazydocker on 13 June 2011, 22:34:42

Can't remember which V6 engine you're using but perhaps an injector feed as you're not having the ABS? :-/ :-/

I would think that either Kevin or 2woody will be the best bet ;) ;)

Title: Re: Tacho reading without ABS module!!
Post by: MartinP on 13 June 2011, 22:50:44

Quote

Can't remember which V6 engine you're using but perhaps an injector feed as you're not having the ABS? :-/ :-/

I would think that either Kevin or 2woody will be the best bet ;) ;)

There only one V6  :D on here  :y

If I only get 1 coil input per revolution, presumably  the Tacho dip switches input the calculation factor to get the correct reading.

The wiring diagram I have put up is for the 100mm unit, I now have to go back as the 80mm unit did not show the selectable dip switches.

will try to get the other drawing up soon as.

Martin

Title: Re: Tacho reading without ABS module!!
Post by: Marks DTM Calib on 14 June 2011, 08:32:44

Er, you cant easily.

The only possible might be to diode OR the three ignition coil feeds together and add a pull-up resistor.....got to be careful with back EMF though!

Title: Re: Tacho reading without ABS module!!
Post by: Kevin Wood on 14 June 2011, 14:41:41

Looks like the same VDO one that I have.

If so, it'll work fine from the ECU tacho output signal that normally feeds the Omega dash (light green wire IIRC). It doesn't need to be fed from a coil. Select 6 cylinders on the dip switch. :y

Kevin

Title: Re: Tacho reading without ABS module!!
Post by: MartinP on 14 June 2011, 21:46:26

Thanks both, I will try and find the output from the ECU then.

Martin

Title: Re: Tacho reading without ABS module!!
Post by: Kevin Wood on 14 June 2011, 22:22:21

Pin 43 on the ECU (Green wire). :y

Title: Re: Tacho reading without ABS module!!
Post by: MartinP on 14 June 2011, 23:22:46

Quote

Pin 43 on the ECU (Green wire). :y

Thanks Kevin, I spent 10 minutes looking at the drawing and couldn't see that for love nor money  ::)

Does the output send a true pulse or a fraction?

The 100mm ETB clocks are cylinder selectable not sure about the 80mm.

Martin

Title: Re: Tacho reading without ABS module!!
Post by: Martin_1962 on 15 June 2011, 08:16:02

Quote

Quote

Pin 43 on the ECU (Green wire). :y

Thanks Kevin, I spent 10 minutes looking at the drawing and couldn't see that for love nor money  ::)

Does the output send a true pulse or a fraction?

The 100mm ETB clocks are cylinder selectable not sure about the 80mm.

Martin

Green wire well know among LPG installs :) :)

Title: Re: Tacho reading without ABS module!!
Post by: Kevin Wood on 15 June 2011, 09:27:30

Quote

Quote

Pin 43 on the ECU (Green wire). :y

Thanks Kevin, I spent 10 minutes looking at the drawing and couldn't see that for love nor money  ::)

Does the output send a true pulse or a fraction?

The 100mm ETB clocks are cylinder selectable not sure about the 80mm.

Martin

It's one (12V IIRC) pulse per ignition event so configure the tacho for 6 cylinders and it should work.

Kevin

Title: Re: Tacho reading without ABS module!!
Post by: Marks DTM Calib on 15 June 2011, 10:24:14

I thought the tacho was a multiple....maybe thats the speed signal then lol (which is why I didn't sudgest it)

Title: Re: Tacho reading without ABS module!!
Post by: Kevin Wood on 15 June 2011, 11:54:01

Quote

I thought the tacho was a multiple....maybe thats the speed signal then lol (which is why I didn't sudgest it)

I think I scoped it when doing the first LPG conversion. The LPG ECUs seem happy with it at any rate.

Kevin

Title: Re: Tacho reading without ABS module!!
Post by: MartinP on 15 June 2011, 23:08:05

Thanks for the info.

Spoke to ETB today, bloke was happier to know the signal was coming from the ECU.
He thinks the Vaux ECU will send a 12v square wave signal, so will configure the Tacho for a V6 and we will see how we go.

Will be calibrated at their works and can be changed if its not right.

I had terminated the Green wire as I thought I didn't need it. Extended it tonight to get it to the dash.

Martin