Using a gas cluster for use of the Tach

[deepgrooves74]

Okay before you guys start saying something like I should learn how to use the search function I have done a lot of research. My question is very specific. I plan on using a 1989 GTI 16 valve cluster that has MFA and also comes with a speed sensor so that I can add cruise control easier to my 1984 rabbit. I might have to add that I am also upgrading to the second-generation wiring harness (CE2) that I acquired from an N/A diese(firewall forward)l, and also an eco-diesel (firewall back to the tail lights)

Here is my specific question…

I plan on using (for ease of simplicity) a Dakota digital module to change the W terminal signal to a useful signal for the tach. Unfortunately I was told by one of the techs there that from 1988 and forward all of the VDO and Motometer gauges used by Volkswagen were changed in terms of the tachometer signal was increased to a very high voltage.

According to some of my local friends that have been doing wiring for years they don't believe that the switchover was until the early 90s.

Are any of you guys aware of this, and when it occurred…

I am just trying to get myself into a gauge that has MFA, and also has the speed sensor at the back of the speedometer… I was truly hoping that I could just use the 1989 gauge that was left behind by my brother when he blew up his GTI. Then I wouldn't have to spend any extra money trying to get another one…

Well just going along with TruForm. My last thread that I started just recently was also long-winded…

[deepgrooves74]

If it helps I can post the part number that's on the back of the cluster in question from 1989.

I started thinking that maybe I could find this information out by chasing the part number, but I haven't gone that far yet.

I figured that maybe this could be something that could be found out in more general terms.

We were under the impression that the only vehicle that might have these newer options with the tachometer signal would maybe be a Helios GLI of the generation.

[TimpanogosSlim]

I'm going to assume that you found and read the relevant threads.

What we need to start with are high resolution pictures of both sides of the circuit board from the tach you hope to use.

[deepgrooves74]

I'm going to assume that you found and read the relevant threads.

What we need to start with are high resolution pictures of both sides of the circuit board from the tach you hope to use.

I can do that... Later this morning. Thx

[deepgrooves74]

These are what I believe to be relevant threads that I checked out:

Concerning the circuits on the back of the tachs

http://www.vwdiesel.net/forum/index.php?topic=3741.0

Here's another thread on the VW vortex. It is where I got the thread above…

http://forums.vwvortex.com/showthread.php?5159346-Hooking-up-Tach-on-diesel

Good usable information in this thread as well…

http://www.vwdieselparts.com/forum/viewtopic.php?t=10095

This is concerning a conversion on a Toyota, but it does talk about the pulses that are supposed to be there… A little bit of useful information.

http://forums.tdiclub.com/showthread.php?t=269288

[TimpanogosSlim]

Full disclosure: i don't know a thing about CE2 harnesses or how tachs work in late mk2 vehicles. but i think we understand the mk1 tach pretty well.

[deepgrooves74]

Full disclosure: i don't know a thing about CE2 harnesses or how tachs work in late mk2 vehicles. but i think we understand the mk1 tach pretty well.

We are in the same boat on that one… The Tach that I am trying to use is actually a CE1. I am sorry that I haven't posted the pictures of the back of the Tach, but I am going to try and get that tonight.

[TimpanogosSlim]

Yeah, I didn't tinker much with my volkswagens until my mk5. so I know mostly mk5 and mk1.