Hi all i have put new set of vdo electronic gauges in my fj holden speedo oil temp fuel tach it has a vr v6 commodore motor wiring loom is from v6 conversion. when i started the car up the needle on the tacho didn't move past zero tacho is 12 volt power earth pulse i connected the way the directions say. I rang Howard instruments in west Heidelberg and he said put a 1k resister between the pulse wire and the power wire. now the tacho idles on 800rpm and i give the car a rev up the needle goes to 1400rpm and drops back to zero if i turn the car of and re-start the car the same thing happens. thanks Gary.
tacho not working
Posted 27 April 2019 - 10:37 AM
Maintain the 1K resistor splice (pull up circuit) between the pulse wire and 12v+ ignition feed.
Connect the tacho pulse wire to the tach output from the ECU, not the coils.
Edited by VDO, 27 April 2019 - 10:38 AM.
Posted 27 April 2019 - 09:08 PM
Thanks VDO which wire do i use from the ECU. Thanks Gary.
Posted 29 April 2019 - 03:14 PM
there is no brown wire with a red trace coming from the ecu. Thanks Gary.
Posted 29 April 2019 - 05:37 PM
Sorry Gary, it comes from the DFI (Direct Fire Ignition Module).
The DFI module is what the coil pack is attached to.
The tach output wire is green.
I'm pretty sure the tach output is only 5 volts, so you need to use the 12 volt pull up as previously explained.
Sorry for the mix up.
Posted 30 April 2019 - 12:07 PM
Hi all i have just taken the coil pack wiring plug of and it dosnt have a green wire in the plug is this the place where it should be or do i look somewhere else. Thanks Gary.
Posted 02 May 2019 - 10:01 AM
I have attached a diagram of the ignition module connections which is attached to the coils.
It shows a BROWN wire which is located at pin E. It's marked Tacho signal out.
Sorry about the brown - green sillyness, but this should be the one.
Posted 14 May 2019 - 03:04 PM
Posted 14 May 2019 - 03:11 PM
Hi all i have connected The tach up and I still have the same problem. Thanks Gary.
Sounds like your tacho movement needs balancing (different to calibrating).
Did you paint the pointer needle by any chance..?
Posted 14 May 2019 - 03:47 PM
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