Diesel tacho info at Samba!

[silverbullet]

I just found this and it could save more than a few quid for anyone wanting to do a clock/tacho swap, assuming you've got the pcb, technically competent and not ham f15ted...
http://www.thesamba.com/vw/forum/viewtopic.php?t=444451
Here's the text (edited) without pics, I don't know what the mentioned "quantum" model is? US quattro?

So I think I've got a fix for the un-obtanium vanagon diesel tach for pretty cheap but some assembly required.
I believe this is known as the CE1 wiring tach with temp & fuel gauge.

But with the exception of the ultra rare Qauntum TD tach or a mega money tach from a euro T3 its impossible. I did manage to find a few Quantum TD tach's & have one installed & working. It did take a complete disassembly of the clusters, not for the feint of heart, but its pretty simple to do if you're careful.

Anyway... from taking apart a few tachometers it would appear to me that all the mid 80's tach's share the same connector, shape, mounting position with the exception of the two very small black screws that hold the face. The diesel's (on my quantum tach) are closer together than the stock vanagon tach.

So anyway from my experiences taking apart Vanagon clusters here's what I propose as the solution to the tach shortage.

Go online & find a used CE2 diesel tach:

I don't believe they are that rare as they were in the majority of the Mk2 diesel Jetta & Golf models from 86-91?

Disassemble it complely (I found a dinner fork works best for removing the pointer) and install the diesel tach module in the place of your existing vanagon unit using the vanagon back / mounting plate. Actually before you install it break the brittle glue (very careful here) that holds the tach speed adjustment potentiometer from losing its cal on the back of the tach module. I used an exacto knife & it was easy to do. Mark where that pot is on the inside of back / mounting plate and drill a small hole in the back plate so you can stick a jewlers flat head screwdriver in to make adjustments later. I'd start with a 3/4 turn clockwise here BTW. Clockwise lowers the tach rpm, counter clockwise raises the tach rpm. Time will tell if vibrations can cause it to rotate & need another cal. The stock calibration read approx 2x high.

**note here, I had to make adjustments because I have a serpentine setup on my engine. The alternator has a smaller diameter clutched pulley which causes the tach to read high. If you still have a v belt alternator you might not need to bother here.**

Now to make it look like a stock tach. Drill the mounting face screw holes if they are different to match how your tach face is secured in the cluster. Some models screw into the actual tach module & others go into bosses on the plastic back/mount plate. Don't worry about messing it up, you could scratch your name in the tach face if you want, it won't matter. Again you might not need to worry about this step as you're reusing your back plate & tach face anyway.

Now email this guy (or do it in advance of taking your cluster apart ) & ask him to reproduce the stock CE2 tach face for you. I got him to make me a custom one years ago & it turned out very nice. I just wish I could find it now...

http://www.thesamba.com/vw/classifieds/ ... ?id=602331

So I think you can see where this is going now. Once you glue the new face to your old gas tach face & assemble it all back you can have a stock appearing diesel tach for a fraction of the cost of the other options.

In the process of installing my 2.02 Quantum tach I thought I killed it by keeping my Dakota Digital box inline to adjust it easier. (you can't & it didn't kill it) Thinking it was dead I installed a 2.22 MK2 jetta tach & it worked as well, it just read a bit higher so I know the alternate diesel tach body will accept the w terminal signal through the stock vanagon cluster wiring. One thing I can't vouch for is that the 2.22's pot has the same range as the 2.02 Quantum tach i'm using. My gut says it will though.

As for performance of the Quantum unit, its accurate now that i've calibrated it. I do find it hangs ever so slightly when engine RPM's are decreasing very slowly. I chose to concentrate on getting the RPM bang on at 3000rpm not idle using a GPS & the final drive ratio's.

Regarding monkeying around inside your cluster, you really can't be to careful with the ribbon circuits. I'm currently trying to find out why my oil pressure LED doesn't want to blink alarms at me anymore. It just wink's once when I first turn on the ignition. (help please!!)

[AngeloEvs]

I did a similar POD conversion but used a TR7 tacho for my WBX'r, it can be done but its for the strongly minded DIY'r...... .

The led problem........does yours have a Buzzer of Doom? if so read on...if not ....go to next post and collect 10 points (it's christmas!)

The BOD circuit controls the 'flashing'. My approach would be:-

Using a Multimeter set to a low ohms range, Check that pin 13 of the multi connector under the dash pod (low oil pressure switch feed) connects to chassis (Engine Off). The single pulse may be generated by the BOD circuit at switch on but extinguishing because the Oil pressure switch is high resistance or open circuit. Pretty sure that BOD buzzer interrogates the High oil pressure switch against RPM but ignores the low oil pressure switch.


Change the LED/clean the legs - LED's generally work or don't but I have known a few to briefly illuminate then go out (or have legs that are badly tarnished and causes them to be intermittent).

Try another buzzer of doom pcb.

Finally, if the above fail then it is some obscure fault that needs to be traced with dash out and on a bench, but someone may just come along and say......."I had that problem and here is what you do!"........merry christmas!

[silverbullet]

The post on samba refers to taking the tacho unit c/w face from the Golf VDO VW instrument pack, as it is so closely related to the T3 one (or are we getting across purposes?)
Not my buzzer problem - all quoted from the samba post...but I will keep it in mind

[AngeloEvs]

Silly me, just read it again and can now see its the originator of the thread with the problem - ah well, never mind , too much JD!.....

[Plasticman]

never mind , too much JD!.....

is there such a thing
mike

[syncroandy]

FWIW I think the 'early' Mk2 Golf/Jetta/Passat(?) tacho faces have the same two cutouts for the water temp and fuel level needles as the T3, the later ones have a single cutout at the bottom. I'm planning to use a Golf GTi 7k tacho face on my WBX tach as (with adjustment) it will suit the EJ25 in my T3 better.