How to install aftermarket tach

[jcbattman]

Wondering if someone can reveal the secret to hooking up an aftermarket tachometer. I'm having problems getting it to work. Its a vdo 333 015. Please just an answer. 87 2.1. I cant believe there is not much info here. Even have auto meter 9116, but that didnt make the tach work. Tested tach on another car, and it works fine. Where do you get the signal from? Which wire in the dash, i tried #9 green wire - didnt work, I ran new wire to coil negative, didnt work. Anybody got the simple answer?

[Pascal]

On my 84 I ran a wire to the coil to pick up the signal. I think it was the positive but can't remember. I can have a look tomorrow.
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'84 Westy - 2.2wbx, GT Torque-Biasing Differential
'91 EA Cabby

[jcbattman]

I think hooking up to positive would fry the tach. Is your 84 a points distributor or electronic

[82westyrabbit]

A after market tac should have a positive wire. A negative wire. And a wire from the negative side of the coil. It could also have a wire for a light. John

[jcbattman]

Yes, it does. I wired it correctly per instructions for a coil system......like i said, it doeznt work that way for a vanagon. Somebody here must know how to properly hook one up?

[9.5isCanadian]

I hooked my sun tach up according to enclosed directions.
Works great.
I’ll look in the AM to confirm coil connections

Owen
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9 1/2 - missing a few pieces.

1987 Getaway Hightop
1980 Sunroof Vanagon
2018 BMW R Nine T
2012 Golf tdi

[jcbattman]

The other way to wire this tach besides the negative side of the coil is to wire it to accesory side of alternator. You have 3 wires, 1=ground, 2=switched 12v power, and 3=negative side of coil or a/c side of alternator. Wires 1 and 2 afe easy, where do i get my source signal #3 from?

[crazyvwvanman]

On Bosch Vanagon alternators it would be labeled with a "W" next to a male spade. All of the Bosch alternators will have the "W" cast into the case near the spot where the male spade would be but it is only actually installed when needed by the vehicle it is built for. It can be easy to confuse, look carefully. If you have the original alternator then you probably don't have a place there ready for you to hook the tach to. Many rebuilt alternators will have it, since the rebuild companies add it so the same alternator will work in more vehicles.

Mark

[jcbattman]

Thanks, i'll give that a try. All the talk about the green wire that goes from -coil to gauge cluster plug, and the tach wiring instructions threw me for a loop I guess. Where do you connect your mechanics dwell/tach meter to, I dont have one anymore and cant remember how its done, should be same for dash tach.

[Zeitgeist 13]

I recently was tuning an '84 w/2.1 and needed a tach to set the timing. I just hooked an old Opel VDO unit up to the alternator for the ground, the 12v positive to a hot start solenoid, and then the tach signal to the coil--easy peasy.

_________________
Casey--

'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik?

[jcbattman]

Unfortunately for me, not easy peazy or whatever, mine doesnt geg signal from coil. Thanks though

[jcbattman]

What is you black wire connected to on your alternator? I dont have a ground on alternator, i have B+ and D+ and W

[Zeitgeist 13]

Every VDO tach I've seen gets its signal from the coil. I went back after this pic was taken and re-checked the timing with another aftermarket VDO tach and it was wired the exact same way. The black wire is just an alligator clip on the alternator for ground. It's always a good idea to ground the alternator with a dedicated wire to the chassis.
_________________
Casey--

'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik?

[jcbattman]

My new vdo tach works great off the negative side of the coil on my 79 rx7, it however does not work off the nevative side of the coil on my vanagon. Cant figure this thing out. Anybody have a real answer? I'm about to throw in the towel.

[82westyrabbit]

If the you know the tac works by hooking it up to another engine and we know you know how to hook it up if you made it work on another engine. than the problem has to be in the wiring. Are you trying to hook it up to existing wires or are you hooking it up in the engine compartment. If you are using existing wires try hooking it up in the engine compartment. The engine runs so we know you have a signal at the negative side of the coil. Have you tried hooking it up in the back like zeitgeist 13 shows? This is a simple problem you have to over thinking it. John

[jcbattman]

Yes, i have been hooking it up in the engine compartment, a wire directly to negative side of coil, a solid ground, and 12v power.

[82westyrabbit]

Do you have a dwel meter. Nobody cares what the dwel is with electronic ignition but it will verify you are getting the proper tac signal it the only thing left. Dose the tac do anything or just sit there dead. John

[jcbattman]

Dont have a dwell meter anymore, it was old and broke. Gonna try and find a dwell/tach this weekend. I tried hooking up the tach again when I got home from work, in the engine bay, and it didnt work. The tach has 3 dip switches, i had them set (per instructions) for - coil setup ( 1=on, 2=off, 3=off). I messed with those, turned 1 off and 2 on and left 3 off, and I got a reading at idle, but it was about 3-4 grand, reved the motor and the tach went down to 0 rpm then back up to 3-4 at idle. At least I got a reading now but its working backwards. Weird huh. Tried it with dip switch 1 off, 2 off, and 3 on with same results.

[jcbattman]