My UK speedo on my UK TT stopped working properly. I got replacement jap dials yesterday and removed the speedo only (not the boost gauge part) fitted a blue 20,000 ohm resistor to the R10 slot. The resistor that was in there before was a 33,000 ohm. Wacked on my UK dial face and fitted the modified Jap clock back into the UK cluster. I put a small cut in the dial face so I wouldn’t have to remove and damage the needle. The Jap dial face went upto 180kph, not sure what the UK shows but they all show the same don’t they?

Anyway, the speedo isn’t showing the right speed, it seems to be about a factor of 2 out, i.e. showing 20mph when going 40mph, or it could be an offset of about 20mph, i.e. shows 0mph up to 20mph then 10mph shown as 30mph, 20 as 40, 40 as 60 etc. the movement of the clock seems fine

Have I installed the right value resistor? Do I need to mess about with the pots to get it to show the right speed? I remember seeing a photo showing where you can drill holes in the casing so you can adjust the pots while it is all still assembled. Where can I find that?

The other problem I have had is that now all of a sudden the boost gauge in the cluster has stopped working. Remember I didn’t swap that out or touch it in anyway so I guess I haven’t plugged something back in properly when putting it back together. Where does the boost gauge get its signal from?

just buy some UK clocks from me for £100.

cheers but no way the jap clocks cost me £37 and the resistor cost me 10p. That is a bargain in my book. I had done the blue led conversion too so dont want to change it about. Im sure it just needs a fiddle to get it right

Assuming they haven't replaced the face with a 120mph one so they don't have to do anything you'll have a 180/190kmh clock. Change the resistor for 20k then use the adjustment pot on the top to get it spot on using gps or another car at a set speed.

 

Not that hard a job, mine had a 120mph faceplate so had o remove that and fit a 180mph one which was a bugger to do as i had to hack all the old glue off again.

 

copied from markw's thread...

 

"The speedo PCB has the speedo dial mounted on it, so you have to disassemble the whole binnacle which is tedious but not too difficult. The only dodgy bit is removing the switch pods- the screw posts fragmented a bit when I took mine apart so I had to buy some longer screws when it came to put it back together.

 

So there are the two options- one is to tweak the existing set-up and the other is to swap the resistor, but you still need to tweak it afterwards to get it reading right.

 

I think the adjuster screw that SRRAE speaks of is the calibration pot which I talk about. I know that there are (at least!) 2 versions of PCB and mine had 2 calibration pots- one for the offset (i.e. it reads 0 when you're not moving) and the other for the scale (sets the range). On mine the pots are at the top of the PCB, so I drilled 2 holes in the speedo housing so that with the binnacle cover off, I could stick a small screwdriver down at twiddle on the move.

 

As far as the resistor change goes, you need to be a bit handy with a soldering iron. You have to desolder the old resistor and then solder in the new one.

 

Useful links:

Binnacle dismantle: http://www.300zx.co.uk/forums/showpost.php?p=297744

My conversion pt1: http://www.300zx.co.uk/forums/showthread.php?t=35682

My conversion pt2: http://www.300zx.co.uk/forums/showthread.php?t=36601

 

The last thread has lots of pics for reference.

 

Mark"

 

ADDITIONAL NOTE THE LEFT HAND ADJUSTER MOVES THE BONGING NOISE LIMIT HIGHER AND LOWER NOT THE OFFSET AS MARK SAYS

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