Edited with one more pic, and also please note I did this on a MotoMeter Cluster. The VDO one maybe different
Hi, So.. I did a swap a while ago on our mk2TD we have and the tach was always off! It showed around 1500 at idle! The reason is the 1.6TD has a V belt system and the 1.9TD has a serp set up with different pulley sizes. Now I asked around to see if anyone knew how to over come this issue, and no one was able to help me. So months of slacking later, I was going to install a clock into my cluster instead of a tach (it was pissing me off that much). But long story short you can't do that
This was my issue. That was my 'idle'
So my solution I found to my problem was. There is a factory "adjustment" that can be made! That no one ever talks about, to fine tune the tach!
Its right around the 5grand mark! If you turn it one way you can make ur idle 3 grand.. hehe.. But that was not the goal! And if you turn it another way, I was able to make the idle drop down to 1grand
yes not exactly 900 rpms.. But still way better...
And to make it adjustable in the car, I drilled a small hole in the side so it can be turned with a small screw driver with out taking it apart every time to make a small adjustment!
Close up shot!
But I wanted 900, so I ended up taking it apart again, and manually moving the needle a slight bit lower, and put it together and readjusted it again
Not sure if anyone cares but solved my problem so I thought I will share!