Vdo Tach Does not read right

kolt10 · Posted: Sat Jul 17, 2010 3:36 pm Post subject: Vdo Tach Does not read right

I installed my vdo tach today,

Image may have been reduced in size. Click image to view fullscreen.

and i connected red(+) to the ignition switch(in-line 3a fuse), then black from (G) to a ground, and the(-) green to the negative side of coil. The gauge works but does not read right. I have read about the diode, but the needle isnt jumpy. Will the diode fix this or should the coil wire be on (G) and the ground on(-)? thanks

edit: reads about 400 at idle and 2500 at wide open

kolt10 · Posted: Sat Jul 17, 2010 4:45 pm Post subject:

This diagram makes me think that maybe i should switch my coil wire to G and the ground to (-). Any thought?

glutamodo · Posted: Sat Jul 17, 2010 6:38 pm Post subject:

Are you sure that's a 4-cylinder tachometer?

All the older VDO tachometers I've seen have the coil input placed between the power connections, and the power connections were always to the + and - . I don't know why yours shows a G on the middle terminal instead of the customary 1 though. Newer ones with an 8-terminal block on the back aren't like that, but older ones with 4-terminal blocks or separate connections are. I think the one shown on that old installation sheet is the 4-terminal block, like shown here in some examples I gathered together:

-Andy

kolt10 · Posted: Sat Jul 17, 2010 7:35 pm Post subject:

well it has 4zyl stamped on it so i assume its 4 cylinder

glutamodo · Posted: Sat Jul 17, 2010 7:37 pm Post subject:

Yeah, that would be for 4. Just didn't spot that in your photos.

kolt10 · Posted: Sat Jul 17, 2010 9:43 pm Post subject:

so what could be the issue. could it be my wiring or the fuse size. someone?

glutamodo · Posted: Sat Jul 17, 2010 9:58 pm Post subject:

Fuse size won't have anything to do with it. I asked if it was 4-cyl since the readings were about half of what you'd expect them to be. Did you try running the coil signal to the "G" terminal and the ground to the "-" and seeing what happened?

kolt10 · Posted: Sat Jul 17, 2010 11:59 pm Post subject:

No i didnt want to fry my tach, i didnt want to chance it. But i guess i will give it a shot

Jody '71 · Posted: Sun Jul 18, 2010 7:56 am Post subject:

Viewing the back of the tach and your instructions, I think The "G" peg should hook up to your coil. At least you don't have to mess with dip switch settings. VDO's instructions were wrong several years ago.
_________________
'66 Beetle
2011 Hyundai Elantra Touring

glutamodo · Posted: Sun Jul 18, 2010 10:50 am Post subject:

kolt10 · Posted: Sun Jul 18, 2010 2:40 pm Post subject:

Across the top it reads 333.230/105/16..... then 4zyl/4takt........12v/233hz........MASSE FREI........10.92, which i believe is the date made

kolt10 · Posted: Sun Jul 18, 2010 2:59 pm Post subject:

ok so i switched the coil to g and now i believe it works properly, its around 700-950 at idle and when i rev it up it will go to 4000 at an idle, so i will drive it tonight and i think it should work. Maybe G stands for green, which is normally the coil wire color Think

, its just a thought.

glutamodo · Posted: Sun Jul 18, 2010 3:13 pm Post subject:

Okay, that's cool, I'm glad it worked.

I don't think it's for green though.
I just about to post this - I was just searching some online for the part number on your tachometer, didn't find it. However I DID find an installation diagram from one that showed that "G" terminal, and on that tach, it was exactly what I suspected above, going to a "W" terminal on an alternator.

it was down towards the bottom of this thread:
http://forums.kombiclub.com/showthread.php?p=279600

a small snippet I took of that diagram for future reference

kolt10 · Posted: Sun Jul 18, 2010 3:18 pm Post subject:

Cool yep that looks like it. Thanks for the help

Gforce · Posted: Mon Sep 26, 2011 4:29 pm Post subject: Vdo tach

The g goes to the coil and the + to power and - to ground


Hello! Log in or Register \| Help \| Donate \| Buy Shirts	See all banner ads \| Advertise on TheSamba.com

	Forum Index -> Beetle - 1958-1967	All times are Mountain Standard Time/Pacific Daylight Savings Time
Page 1 of 1