tacho wiring

[dink]

I have a dashpod and tacho from a petrol t3 to fit into my t3, I have some spare terminals for the multi plug and I can figure out that end, I cannot figure out where the other end of the wire goes on the engine
I have the big thick bentley book, and the wiring diagrams in the mistify me
do I need a special alternator with a specific terminal on the back, or will it work on any alternator
although I need to change alternators anyway

help a dumb ass, please

[AngeloEvs]

Is your engine diesel? Only these need to take the tacho signal from the alternator, petrol models take the signal from the coil. Best to say which engine you have.

[dink]

sorry dumb ass struck
engine is 1.9DG petrol

which side of the coil

[AngeloEvs]

What year Van? The tacho signal may already be at the dash PCB so no need to route a new cable.

[Aberdeenbus]

Hi
this might be of help.it certainly worked for me

http://www.oldvolkshome.com/late_van_cl ... nstall.pdf" onclick="window.open(this.href);return false;

cheers
Si

[dink]

van is '85
august I think
I know there was a empty bit in the multiplug, I have a short peice of wire with the right plug on it from another loom

[AngeloEvs]

Pin 9 on the multiconnector colour coded green reserved for the tacho (even if not fitted), if its blank then you will need to run a feed but check first.

[dink]

Pin 9 on the multiconnector colour coded green reserved for the tacho (even if not fitted), if its blank then you will need to run a feed but check first.

thank you
is that it, do I just connect it to the tacho and that's it, or does it need another wire to make the circuit
I guess a loose wire ran around outside will tell me, before I start adding to the loom

[AngeloEvs]

Three leads on a tacho (sometimes four/five for the bulb if third party tacho fitted) but essentially a positive 12V, a ground or earth and the ignition pulse input (the green wire connects to this). These are the main wires that a tacho requires.

[dink]

Three leads on a tacho (sometimes four/five for the bulb if third party tacho fitted) but essentially a positive 12V, a ground or earth and the ignition pulse input (the green wire connects to this). These are the main wires that a tacho requires.

is this an aftermarket tacho, or VW in the dash pod
this one has gotten me confused now
pin #9, is that it, or are there others

[AngeloEvs]

If you are using an original VW dash with the integral tacho and correct flexi pcb it will be powered and earthed by the PCB. Conx 9 (colour coded green) at the multiconnector provides the trigger pulse for the tacho from the ignition coil and this also connects via the flexi pcb to the tacho. I was under the impression that you had fitted a new/replacement multipin connector to the original loom and were asking which colour cable is used to supply the tacho pulse or if additional wiring was required.

[dink]

If you are using an original VW dash with the integral tacho and correct flexi pcb it will be powered and earthed by the PCB. Conx 9 (colour coded green) at the multiconnector provides the trigger pulse for the tacho from the ignition coil and this also connects via the flexi pcb to the tacho. I was under the impression that you had fitted a new/replacement multipin connector to the original loom and were asking which colour cable is used to supply the tacho pulse or if additional wiring was required.

the loom in the van is currently untouched, the dashpod is vanagon, petrol from the US
I bought the multiplug from a scrap bus
so I had spare pins so I need to add a cable to pin #9
rather than trace an extra wire through the van to pick up on the coil, could I pick up the wire someplace else, fuse box, back of the ignition

[AngeloEvs]

As far as I can see, Terminal 1 of the ignition coil for all models with electronic ignition (already a green wire on that terminal). Alternatively you could try wrapping a few turns of the new wire around the coil HT lead to form a tight coil and use the 'induction' method to provide the pulses (if you have a non standard coil) but never tried it on a VW tacho.

[dink]

As far as I can see, Terminal 1 of the ignition coil for all models with electronic ignition (already a green wire on that terminal). Alternatively you could try wrapping a few turns of the new wire around the coil HT lead to form a tight coil and use the 'induction' method to provide the pulses (if you have a non standard coil) but never tried it on a VW tacho.

thanks,I will give that a try, the coil is a recent genuine VW coil