Tachometer Installation: VW Passat 1.6TD 1992

Good day!

I have a tachometer (RPM gauge) with a W-terminal. How can I connect it to my car? Can I use any tachometer, even one designed for gasoline engines, or does it have to be a specific one for diesel vehicles? (Ignoring the RPM range for now).

"On eBay, you can often find DZMs (presumably referring to some kind of module or device) for Smart cars. Additionally, I've learned that these need to be activated by a Smart Center when installed in a Smart car... Could I potentially use one of these?"

Is there an original DZM (digital tachometer), perhaps a combination instrument panel, available for the car?

Sincerely,
Gerald.

Hi, with your Passat, you will only be able to install an original Passat TD instrument cluster without making any major modifications.

That should be straightforward, as all the cables should already be in place. I did it myself on my 1987 Golf 2 diesel.

The Smart DZM will definitely have nothing in common with the way the 92 TD displays the DZ.

m;

Good day!

Thank you for the quick response. So, I'm now looking for sources for an original DZM. I wouldn't mind doing some tinkering, but I need to know what I actually have to do.
There's a signal for the tachometer at the W terminal. But how does it proceed from there?

Best regards,
Gerald.

"Some cars already have the W-connector installed! Is the connector for the W-connector already plugged in? If so, the same wire color should be present on the connector of the speedometer unit. Otherwise, you need to run a wire from the alternator to the speedometer unit. Instead of the clock, install a tachometer. The circuit board is usually already equipped with terminals for the tachometer. Look for a free wire on the connector of the speedometer unit and trace the circuit board to see if it actually leads to the tachometer; then connect the wire there."

I've done it on my Golf II and VW T3 bus! It works great! If the tachometer reading is not correct, there is a white sticker behind the tachometer; remove it, and you'll find an adjustment screw!

Hello!

"Yes, there's already a cable connected to the W-terminal. With a little effort, I'm sure I can find it behind the dashboard. However, I'd prefer a separate tachometer, because a clock also has its appeal, especially since they tend to be quite accurate. Where can I find tachometers that could be installed instead of the clock?"

Best regards,
Gerald.

Hmm, it's a matter of taste! There's also another tachometer unit that includes DZM and a digital clock, which would be the easiest option! Otherwise, you can buy a DZM at an accessory store or online. You'll need the + and - terminals, as well as a W-terminal for the signal, and possibly connections for the lighting.

Okay, so the plus/minus and lighting are clear. The W connection to the tachometer is also okay. Is there only one type of tachometer? Or are there gasoline tachometers and diesel tachometers? Can I connect ANY tachometer to the W terminal?

Best regards,
Gerald.

No, those gasoline tachometers won't work there! Older gasoline tachometers, for example, from a Golf II, are compatible.
"Terminal 1 for ignition pulses (usually directly connected to the ignition coil terminal 1). In diesel engines, the DZM (digital tachometer) receives signals via the alternator's W-terminal; the faster the alternator spins, the more pulses it sends. In more modern cars, almost everything is controlled by the engine control unit (ECU)."

Hello,

wampera wrote:

Is there an original DZM (digital tachometer), perhaps a combination instrument panel, available for the car?

Yes, they exist. And I would strongly recommend getting one, because if you buy a diesel rev counter for a 35i separately, you'll be disappointed. It used to be plug-and-play; a Golf rev counter would plug directly into the dashboard of the 32b (because the dashboard was the same). From model year 1985(?), there's a W-signal everywhere, all the way to the dashboard module, due to the dynamic oil pressure control (including in the T3 ).
Regarding the 35i: In this model, the drum motor is simply the motor itself, without any built-in processing electronics. The electronics are located on the main board (or, in the clock-equipped version, are not present).
So: either buy a complete diesel instrument panel (rarely available) or a suitable external tachometer from a third-party manufacturer.

Best regards, Uli.

Thank you for the explanations. I will start looking for it.

Sincerely,
Gerald.