The Ultimate Tacho Thread

[253@7k]

Ok I have decided to do my own little bit of cleaning, so please take notice before asking "how do I install a tacho?"

In this thread you will find links to all kinds of info on tachos. Threads have covered:

How to install tachos,
Troubleshooting with tachos and
Why the hell do you need a tacho in the first place?

These threads should supply you with all the info you need. (And stop the need for more tacho threads)

Here we go.....

Finding the "brown wire"

Wiring tachos (vn onwards)

Why do you need a tacho arguement


More wiring solutions (VY)

Solving problems with your tacho signal

And these are just some of the ten thousand million that exist.

So, to conclude:

VB-VL= signal wire to coil.

VN-VX= Signal wire is brown wire near strut tower.

VY V6= Signal wire is solid brown wire in the loom infront of the coil pack.

VN's have signal problems. (Some dont send correct signal. Fix with tach adapter)

These should answer just about any questions you may have. If you need to see what I have said repeated 1000 times just do a search on "tacho".

Just rember, your commodore probably already has a damn tacho.

Steve.

[Anonymous]

thankyou, hopfully we wont get anymore tacho threads with questions asked a million times

[Goon]

My VC's Speco tacho

Green to coil
Red to 12v accessory
Black to Negative
White for light, but thats not connected.

[Pub24/7]

What's involved in recalibrating a tacho eg vh sle v8 tocho down to a 202 would recalibration be needed?

[Anonymous]

Originally Posted by Pub24/7

What's involved in recalibrating a tacho eg vh sle v8 tocho down to a 202 would recalibration be needed?

yes, it will need to be changed to suit the 6cyl. if its a stock tacho im not sure if it can be done. if its aftermarket there should be a switch at the back of the tacho.

[Pub24/7]

Goon mine is an actual in dash original tacho like instead of where the vac gauge would be. Slundy can you help me will it need doing or should it be right?

[253@7k]

Originally Posted by Pub24/7

What's involved in recalibrating a tacho eg vh sle v8 tocho down to a 202 would recalibration be needed?

Hmm, for some reason my post did not come up. I'll post it again.

From what I can tell, changing a v8 tacho to a 6 tacho just requires a resistor in the tacho to be changed. That is as far as I have gotten, I cannot seem to find the exact resistance that is needed. I think we need an elec expert.

[Pub24/7]

ok thats cool i havent really looked at it yet and not going to do it yet so i'll pull it apart and have a look

[.]

Stickied

Recalibrating a tacho cannot be done via a resistor. Putting in a resistor will stop the tacho altogether. Tachos work on pulses of 12 Volts. So, by putting in a resistor it still pulses just at a lower voltage causing the tacho to stop working at all.

Check on the back of your dashboard circuitry. You MAY find a little switch

[253@7k]

Originally Posted by 12Voltking

Stickied

Recalibrating a tacho cannot be done via a resistor. Putting in a resistor will stop the tacho altogether. Tachos work on pulses of 12 Volts. So, by putting in a resistor it still pulses just at a lower voltage causing the tacho to stop working at all.

Check on the back of your dashboard circuitry. You MAY find a little switch

Glad your here to keep us on the strait and narrow, cheers.

Steve.

[bangers]

Originally Posted by slundy

So, to conclude:

VB-VL= signal wire to coil.

incorrect. the signal wire on a VL does NOT go to the coil! there is a wire behind the instrument cluster. the coil is a multi spark system i believe and will give an incorrect reading. in the Gregory's manual it says there is a signal wire hanging behind the alternator but that is incorrect too, it is only a test wire.

[253@7k]

Ah yes bangers, my mistake I forgot about the rb30's. However V8's should still be able to go to the coil though right?

[bangers]

i imagine so as the V8 didn't have an ECU. but then like the RB30 the wiring loom may be the same for auto and manual. i can't say for certain.

[.]

Either way....the wire will always be behind the dash as well....